Power Automate Expression Syntax: Complete Cheat Sheet (2026)

Power Automate expression syntax is the formula language used inside flow actions — the same Workflow Definition Language (WDL) engine that runs Azure Logic Apps (Microsoft Learn, 2026). You write expressions in the expression editor tab of any action input field: click the field, select "Expression", type your function, and click OK. The result replaces the field value at run time.

Two forms exist. Inline — @{functionName(args)} — embeds the result inside a string, so Hello @{triggerOutputs()?['body/Name']} produces Hello Rizwan. Pure expression — just functionName(args) with no @{} wrapper — returns the raw value and is what you use in the expression editor. Mixing them in the same field causes parser errors.

Key Takeaways

- Power Automate expressions use Workflow Definition Language (WDL) — the same engine as Azure Logic Apps (Microsoft Learn, 2026).

- Use @{...} only for inline string interpolation; use bare functionName() in the expression editor tab.

- The ? operator makes any property access null-safe: body('Get_item')?['value'] never throws on a missing field.

- coalesce() is the fastest fix for null values from SharePoint, Dataverse, or HTTP responses.

- All 60+ functions in this cheat sheet are copy-paste ready with live examples.

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Expression Syntax Basics

Power Automate expressions follow a strict parser. Get these rules wrong and you'll see InvalidTemplate before the flow even runs.

The two forms

# Pure expression (use in the Expression tab):
concat('Hello', ' ', triggerOutputs()?['body/Name'])
# Inline interpolation (embed inside a text field):
Hello @{triggerOutputs()?['body/Name']}, your order is @{outputs('Get_order')?['body/Status']}

Never wrap a pure expression in @{...} in the expression editor — the parser will double-evaluate it and produce a string that starts with a literal @.

Quote rules

Single quotes delimit string literals. Double quotes are not valid inside expressions and will break the parser:

# Correct
replace(triggerOutputs()?['body/Title'], 'Draft', 'Final')
# Broken — double quotes cause InvalidTemplate
replace(triggerOutputs()?["body/Title"], "Draft", "Final")

To include a literal single quote in a string, escape it by doubling: 'O''Brien'.

Null safety with ?

The ? operator on a property access returns null instead of throwing when the property doesn't exist. Use it on every dynamic content reference:

# Throws if 'Manager' is null in SharePoint People column
triggerOutputs()?['body/Manager/Email']
# Safe — returns null instead of crashing
triggerOutputs()?['body/Manager']?['Email']

Chain as many ? as you need. Combine with coalesce() to substitute a default when null comes through.

Operator precedence

Power Automate expressions don't support infix math operators (+, -, *, /). Use functions: add(), sub(), mul(), div(), mod(). Parentheses control evaluation order inside function arguments exactly as you'd expect.

How to test any expression

Drop a Compose action into your flow, paste the expression in its input, and run the flow. The Compose output shows exactly what the expression returns — invaluable before wiring a complex expression into a Send Email or Condition action.

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Power Automate Expressions List (All Functions A–Z)

Quick index — every function covered in this post, alphabetically. Click any category header to jump to the full table.

Function	Category	Returns
add	Math	Sum of two numbers
addDays	Date/Time	Timestamp ± N days
addHours	Date/Time	Timestamp ± N hours
addMinutes	Date/Time	Timestamp ± N minutes
addSeconds	Date/Time	Timestamp ± N seconds
and	Logic	true if all conditions true
base64	Conversion	Base64-encoded string
base64ToString	Conversion	Decoded UTF-8 string
bool	Conversion	Boolean true/false
chunk	Array	Array split into sub-arrays
coalesce	Logic	First non-null value
concat	String	Joined strings
contains	String / Array	true if item found
convertTimeZone	Date/Time	Timestamp in target time zone
createArray	Array	New array
dateDifference	Date/Time	Difference as duration
dayOfMonth	Date/Time	Day number (1–31)
dayOfWeek	Date/Time	Day number (0=Sunday)
decodeBase64	Conversion	Decoded string
decodeUriComponent	Conversion	URL-decoded string
div	Math	Quotient (integer)
empty	Logic	true if null/empty
endsWith	String	true if ends with
equals	Logic	true if values equal
first	Array	First element
float	Conversion	Floating-point number
formatDateTime	Date/Time	Formatted date string
formatNumber	String	Formatted number string
getFutureTime	Date/Time	Timestamp N units from now
getPastTime	Date/Time	Timestamp N units ago
greater	Logic	true if value1 > value2
greaterOrEquals	Logic	true if value1 >= value2
if	Logic	Conditional value
indexOf	String	Position of substring
int	Conversion	Integer
intersection	Array	Common items
join	Array	Array joined to string
json	Conversion	Parsed JSON object
last	Array	Last element
length	String / Array	Count
less	Logic	true if value1 < value2
lessOrEquals	Logic	true if value1 <= value2
mod	Math	Remainder
mul	Math	Product
not	Logic	Negated boolean
nthIndexOf	String	Nth occurrence position
or	Logic	true if any condition true
replace	String	String with substitutions
reverse	Array	Reversed array
skip	Array	Array minus first N
sort	Array	Sorted array
split	String	Array from split
startsWith	String	true if starts with
string	Conversion	String representation
sub	Math	Difference
substring	String	Substring by index
take	Array	First N elements
ticks	Date/Time	Tick count (100-ns units)
toLower	String	Lowercase string
toUpper	String	Uppercase string
trim	String	Whitespace-trimmed string
union	Array	Merged array (deduped)
uriComponent	Conversion	URL-encoded string
xml	Conversion	XML object

All functions are documented at Microsoft Learn — Workflow Definition Language Functions Reference.

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String Functions

Power Automate provides 16 string functions covering concatenation, search, replacement, padding, and formatting. These are the functions you'll use in nearly every flow that handles user data, file names, or email content — all documented in the Microsoft Learn WDL reference.

Function	Syntax	Example	Output
concat	concat(text1, text2, ...)	concat('Hello', ' ', 'World')	Hello World
substring	substring(text, startIndex, length)	substring('PowerAutomate', 5, 8)	Automate
replace	replace(text, oldText, newText)	replace('Hello World', 'World', 'Flow')	Hello Flow
split	split(text, delimiter)	split('a;b;c', ';')	["a","b","c"]
toLower	toLower(text)	toLower('HELLO')	hello
toUpper	toUpper(text)	toUpper('hello')	HELLO
trim	trim(text)	trim(' hello ')	hello
indexOf	indexOf(text, searchText)	indexOf('Hello World', 'World')	6
nthIndexOf	nthIndexOf(text, searchText, n)	nthIndexOf('a.b.c.d', '.', 2)	3
length	length(text)	length('Power')	5
startsWith	startsWith(text, searchText)	startsWith('PowerAutomate', 'Power')	true
endsWith	endsWith(text, searchText)	endsWith('report.pdf', '.pdf')	true
contains	contains(text, searchText)	contains('Hello World', 'World')	true
formatNumber	formatNumber(number, format)	formatNumber(1234.5, 'C2')	$1,234.50

String tips

Use concat() instead of the @{...} inline syntax when combining more than two dynamic values — it's easier to debug. When checking user input, always wrap in toLower() or toUpper() first so comparisons are case-insensitive. Use nthIndexOf() to locate the second or third occurrence of a delimiter (e.g., finding the second dot in a version string like 1.20.3).

Power Automate cloud flows don't have a native padLeft() expression — use formatNumber() instead for zero-padded integers: formatNumber(triggerOutputs()?['body/ID'], '000000') turns 42 into 000042. For arbitrary string padding, the workaround is substring(concat('000000', string(triggerOutputs()?['body/ID'])), sub(length(concat('000000', string(triggerOutputs()?['body/ID']))), 6)).

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Date and Time Functions

Power Automate stores every timestamp internally as UTC. These 13 functions handle formatting, arithmetic, and time-zone conversion — the three tasks you'll need for every flow that touches dates in emails, SharePoint columns, or approval deadlines. The formatDateTime() format strings follow the .NET DateTimeFormat conventions (Microsoft Learn).

Function	Syntax	Example	Output
utcNow	utcNow(format?)	utcNow('yyyy-MM-dd')	2026-06-24
addDays	addDays(timestamp, days, format?)	addDays(utcNow(), 7, 'yyyy-MM-dd')	7 days from now
addHours	addHours(timestamp, hours, format?)	addHours(utcNow(), -3)	3 hours ago
addMinutes	addMinutes(timestamp, minutes)	addMinutes(utcNow(), 30)	30 min from now
addSeconds	addSeconds(timestamp, seconds)	addSeconds(utcNow(), 90)	90 seconds from now
formatDateTime	formatDateTime(timestamp, format)	formatDateTime(utcNow(), 'MM/dd/yyyy')	06/24/2026
convertTimeZone	convertTimeZone(timestamp, source, dest, format?)	convertTimeZone(utcNow(), 'UTC', 'Eastern Standard Time', 'hh:mm tt')	08:30 AM
getPastTime	getPastTime(interval, timeUnit, format?)	getPastTime(7, 'Day', 'yyyy-MM-dd')	7 days ago
getFutureTime	getFutureTime(interval, timeUnit, format?)	getFutureTime(1, 'Month', 'yyyy-MM-dd')	1 month from now
dayOfWeek	dayOfWeek(timestamp)	dayOfWeek('2026-06-24')	3 (Wednesday)
dayOfMonth	dayOfMonth(timestamp)	dayOfMonth('2026-06-24')	24
ticks	ticks(timestamp)	ticks('2026-01-01')	Tick count
dateDifference	dateDifference(startDate, endDate)	dateDifference('2026-01-01', '2026-06-24')	174.00:00:00

Date tips

formatDateTime() uses .NET custom date format strings. Common patterns: yyyy-MM-dd for ISO, MM/dd/yyyy for US, dd/MM/yyyy for EU, dddd, MMMM d, yyyy for display. Always convert to the user's time zone with convertTimeZone() before including dates in emails — Power Automate stores every timestamp as UTC internally.

getPastTime and getFutureTime are cleaner than addDays(utcNow(), -7) when you want a fixed offset from now. Valid timeUnit values: Second, Minute, Hour, Day, Week, Month, Year.

Use ticks() to compare two dates numerically — subtract them, then divide by 864000000000 to get days:

div(sub(ticks(outputs('DueDate')), ticks(utcNow())), 864000000000)

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Collection and Array Functions

Power Automate has 14 collection and array functions. They work on arrays returned by "List rows", "Get items", and HTTP responses — anywhere a multi-value result comes back and needs filtering, slicing, or merging before the next action. The PnP community maintains real-world examples of these patterns in SharePoint flows at PnP Samples if you need more context beyond this reference.

Function	Syntax	Example	Output
first	first(collection)	first(createArray('a','b','c'))	a
last	last(collection)	last(createArray('a','b','c'))	c
length	length(collection)	length(createArray('a','b','c'))	3
contains	contains(collection, value)	contains(createArray('a','b'), 'b')	true
join	join(collection, delimiter)	join(createArray('a','b','c'), '; ')	a; b; c
split	split(text, delimiter)	split('a,b,c', ',')	["a","b","c"]
union	union(collection1, collection2)	union(createArray(1,2), createArray(2,3))	[1,2,3]
intersection	intersection(col1, col2)	intersection(createArray(1,2,3), createArray(2,3,4))	[2,3]
skip	skip(collection, count)	skip(createArray('a','b','c'), 1)	["b","c"]
take	take(collection, count)	take(createArray('a','b','c'), 2)	["a","b"]
createArray	createArray(item1, item2, ...)	createArray(1, 2, 3)	[1,2,3]
reverse	reverse(collection)	reverse(createArray(1,2,3))	[3,2,1]
sort	sort(collection, sortBy?)	sort(createArray(3,1,2))	[1,2,3]
chunk	chunk(collection, size)	chunk(createArray(1,2,3,4,5), 2)	[[1,2],[3,4],[5]]

Array tips

Use empty() to check if an array has items before looping. Combine skip() and take() for pagination. union() also merges two objects (not just arrays), which is useful for building dynamic JSON payloads.

chunk() is useful when you need to process a large SharePoint list in batches — split the ID array with chunk(), then loop over each sub-array. sort() works on arrays of strings or numbers; for complex objects, sort inside a Select + Apply to Each combination. reverse() is handy when you want the most recent item from a sorted list without reversing the sort order in a query.

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Logical Functions

Function	Syntax	Example	Output
if	if(expression, valueIfTrue, valueIfFalse)	if(equals(1,1), 'yes', 'no')	yes
equals	equals(value1, value2)	equals(toLower('Hello'), 'hello')	true
and	and(expr1, expr2)	and(greater(5,3), less(5,10))	true
or	or(expr1, expr2)	or(equals(1,2), equals(1,1))	true
not	not(expression)	not(equals(1,2))	true
greater	greater(value1, value2)	greater(10, 5)	true
greaterOrEquals	greaterOrEquals(value1, value2)	greaterOrEquals(5, 5)	true
less	less(value1, value2)	less(3, 5)	true
lessOrEquals	lessOrEquals(value1, value2)	lessOrEquals(5, 5)	true
empty	empty(value)	empty('')	true
coalesce	coalesce(value1, value2, ...)	coalesce(null, null, 'default')	default

Logic tips

Don't nest if() more than two levels deep — it becomes unreadable and hard to debug. Use a Condition action instead for branching. coalesce() is the go-to fix for null values from SharePoint People columns, Dataverse lookups, and HTTP responses — it returns the first non-null value. You can use it to provide fallbacks for optional fields without a separate null check:

coalesce(triggerOutputs()?['body/Manager/Email'], triggerOutputs()?['body/Owner/Email'], 'admin@contoso.com')

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Math Functions

Power Automate has no infix operators — there is no +, -, *, or / syntax. Every arithmetic operation requires an explicit function call. This surprises developers coming from Excel formulas or Power Fx, but the WDL parser simply doesn't support operator notation (Microsoft Learn).

Function	Syntax	Example	Output
add	add(num1, num2)	add(10, 5)	15
sub	sub(num1, num2)	sub(10, 5)	5
mul	mul(num1, num2)	mul(4, 3)	12
div	div(num1, num2)	div(10, 3)	3 (integer)
mod	mod(num1, num2)	mod(10, 3)	1

Math tips

div() performs integer division — div(10, 3) returns 3, not 3.333. To get a float result, convert one operand first: div(float(10), 3). Chain functions for compound calculations: add(mul(3, 4), mod(10, 3)) gives 13. For percentage calculations, use mul(div(float(part), float(total)), 100) — the float() conversions are required or the intermediate div() will truncate.

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Conversion Functions

Type mismatches are the most common cause of InvalidTemplate and ExpressionEvaluationFailed errors in production flows. These 11 functions handle every type conversion you'll need — between strings, numbers, booleans, JSON, XML, and encoded formats. When in doubt, call string() before passing a value to a string function or int() before arithmetic.

Function	Syntax	Example	Output
int	int(value)	int('42')	42
float	float(value)	float('3.14')	3.14
string	string(value)	string(42)	"42"
bool	bool(value)	bool(1)	true
json	json(value)	json('{"name":"test"}')	JSON object
xml	xml(value)	xml('1')	XML object
base64	base64(value)	base64('Hello')	SGVsbG8=
base64ToString	base64ToString(value)	base64ToString('SGVsbG8=')	Hello
decodeBase64	decodeBase64(value)	decodeBase64('SGVsbG8=')	Hello
uriComponent	uriComponent(value)	uriComponent('hello world')	hello%20world
decodeUriComponent	decodeUriComponent(value)	decodeUriComponent('hello%20world')	hello world

Conversion tips

Use json() when an HTTP response body comes back as a string instead of a parsed object — this happens with some older REST APIs and SharePoint REST endpoints that return Content-Type: text/plain. Use xml() for SharePoint SOAP service responses. base64() and base64ToString() are commonly needed when working with attachment content in connectors like Outlook or OneDrive. uriComponent() is essential when you're building query string parameters dynamically — without it, spaces and special characters break the URL silently.

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Common Production Patterns

These are the expressions you'll copy-paste most often in real flows — tested patterns for the date formatting, null handling, HTTP parsing, and subject-line building scenarios that come up in almost every approval or notification flow.

Format a date for emails

When SharePoint returns an ISO timestamp and you need a clean display date:

formatDateTime(triggerOutputs()?['body/Created'], 'MMMM d, yyyy')

Output: June 24, 2026. For the US short format: formatDateTime(..., 'M/d/yyyy').

Get file extension from a filename

last(split(triggerOutputs()?['body/{FilenameWithExtension}'], '.'))

Splits report-final.pdf on . and returns pdf. Works for any delimiter-based extraction.

Null-safe field access with fallback

coalesce(triggerOutputs()?['body/Manager/Email'], 'no-manager@contoso.com')

For numeric fields that might be null:

coalesce(triggerOutputs()?['body/Amount'], 0)

Build a dynamic email subject

concat('[', triggerOutputs()?['body/Department'], '] ', triggerOutputs()?['body/RequestType'], ' - ', triggerOutputs()?['body/Title'])

Output: [Finance] Purchase Order - Office Supplies Q2

For end-to-end approval flows using this pattern, see the Power Automate document approval workflow guide.

Calculate days between two dates

div(sub(ticks(outputs('EndDate')), ticks(outputs('StartDate'))), 864000000000)

Each tick is 100 nanoseconds; 864000000000 ticks = 1 day. For business-days counting (excluding weekends), store holidays in a SharePoint list and subtract them in a loop.

Parse a JSON response from an HTTP action

json(body('HTTP_Request'))?['results']

Safe nested access:

coalesce(json(body('HTTP_Request'))?['data']?['value'], 'Not found')

For calling external APIs with OAuth from Power Automate flows, see the custom connectors guide.

Build styled HTML for email output

Expressions can build HTML strings inline:

concat('<b>', triggerOutputs()?['body/Title'], '</b><br/>', formatDateTime(triggerOutputs()?['body/DueDate'], 'MMMM d, yyyy'))

For applying CSS to HTML tables generated by flows, see Power Automate HTML table styling with CSS.

Practical note: the expression editor in Power Automate (and the underlying WDL engine) shares its function library with Azure Logic Apps. If you find a function in the Logic Apps reference that isn't in the Power Automate UI docs, try it anyway — it usually works. Microsoft keeps the two runtimes in sync but the UI docs sometimes lag by months.

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Quick Reference: Expression Editor Shortcuts

A few things that trip up new users every time:

• Accessing dynamic content in expressions: Use triggerOutputs(), outputs('ActionName'), or body('ActionName') to reference values — never paste raw dynamic content tokens into the expression editor.

• Optional chaining: The ? operator (e.g., body('Get_item')?['value']) prevents errors when a property doesn't exist.

• Nested quotes: Use single quotes inside expressions. Double quotes break the parser.

• Testing expressions: Use a Compose action — the output shows exactly what the expression returns before you wire it into something consequential.

• Type mismatches: If equals() returns false when you expect true, one side is probably a string and the other is an integer. Use int(), float(), or string() to normalize.

Try functions interactively before adding them to your flow using the Power Automate Expressions tool — test any expression against sample data right in the browser. The same expression patterns apply in Power Apps canvas formulas, too — see the Power Apps canvas app + SharePoint guide for side-by-side examples.

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Common Expression Syntax Errors and Fixes

These are the errors Power Automate throws most often when expression syntax is wrong — with the exact message and what to change.

InvalidTemplate on save

Full error:

InvalidTemplate. Unable to process template language expressions in action '...' inputs at line '...' and column '...': '...'. Please see https://aka.ms/logicexpressions for usage details.

Causes and fixes:

Root cause	Fix
Double quotes inside expression	Replace "value" with 'value'
Unmatched parentheses	Count opening vs closing parens — add a missing )
@{...} wrapper inside the expression editor	Remove the @{ and } — they're for inline interpolation only
Referencing an action name with spaces	Wrap in quotes: outputs('My Action') not outputs(My Action)

ExpressionEvaluationFailed at runtime

Full error:

The execution of template language expression '...' failed: 'The template language function '...' expects its parameter to be a string...

Type mismatch. SharePoint list columns return different types depending on the field type. A Number column returns an integer; pass it to a string function and you'll hit this. Fix with string(triggerOutputs()?['body/Count']).

NullValueInArgumentError at runtime

The execution of template language expression 'first(triggerOutputs()?['body/value'])' failed: '...array was null or empty'.

The array was empty. Wrap with an empty() guard:

if(empty(triggerOutputs()?['body/value']), 'No items', first(triggerOutputs()?['body/value'])?['Title'])

ActionInputsNotFound for dynamic content

This isn't an expression syntax error — it means the action you're referencing in outputs('ActionName') doesn't exist or has been renamed. Check the internal name of the action (visible in the "..." menu of the action → rename) and update the expression.

div() returns 0 unexpectedly

div() is integer division. div(5, 10) returns 0 not 0.5. Convert to float first:

div(float(5), float(10))

From real flows: the most common syntax error I see in shared flow templates is action names with special characters — Get item becomes Get_item internally but Get_item_2 if it was renamed. Always use the Dynamic Content pane to grab the exact internal name rather than guessing the string to put inside outputs().

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FAQ

What is Power Automate expression syntax?

Power Automate expression syntax is the Workflow Definition Language (WDL) formula system shared with Azure Logic Apps (Microsoft Learn, 2026). Expressions use a function-call form — functionName(arguments) — and are entered in the Expression tab of any action field. They let you transform, compare, and compute values at flow runtime rather than relying on static inputs.

What is the difference between concat() and inline @{...} syntax?

concat() is a function you call in the expression editor. @{...} is an interpolation syntax you use directly in text fields (not the expression tab) to embed an expression result mid-string. They produce the same output but live in different places. Use concat() when you need to combine more than two values — it's easier to debug. Use @{...} for simple inline substitutions in text fields like email subjects.

Can you nest expressions inside other expressions?

Yes — this is how most real expressions work. if(empty(triggerOutputs()?['body/Email']), 'N/A', toLower(triggerOutputs()?['body/Email'])) is a nested expression combining if, empty, and toLower. Watch your parentheses — one missing ) causes InvalidTemplate with a line/column pointer that's often off by one.

How do you handle time zones in Power Automate?

All timestamps in Power Automate are stored as UTC internally. Use convertTimeZone(utcNow(), 'UTC', 'Eastern Standard Time', 'hh:mm tt') before displaying dates to users. The full list of supported time zone names is in the Microsoft Learn reference — use the Windows time zone name format (e.g., Eastern Standard Time, not America/New_York).

Why does equals() return false when both values look the same?

Almost always a type mismatch or a case difference. SharePoint columns return typed values — a Yes/No column returns a boolean, not the string "true". Use string() or int() to normalize before comparing, and toLower() when comparing user-entered text. Use a Compose action to inspect both sides individually before debugging the equals() call.

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What's Next

• Power Automate Document Approval Workflow — end-to-end flow using expressions for dynamic email subjects and conditional routing

• Power Automate HTML Table Styling with CSS — applying expressions to build formatted HTML in flow emails

• Power Platform Custom Connectors REST API Guide — building connectors that consume the JSON outputs your expressions parse

• Microsoft Learn — WDL Functions Reference — the canonical function reference with full parameter specs