PowerShell Format Operator (-f): Format Strings and Replace Placeholders

The PowerShell format operator -f builds a string from a template. Put numbered placeholders like {0} and {1} in the string on the left, and the values on the right:

$name = 'Maria Lopez'
$tickets = 7
'{0} has {1} open tickets.' -f $name, $tickets

Output:

Maria Lopez has 7 open tickets.

PowerShell drops each value into its placeholder, in order. The same placeholders also take number, date and width formats, which is where -f beats plain double quotes.

In this tutorial, I’ll show you how to format strings in PowerShell with the -f operator: numbers, currency, padding, dates and escaped braces. You’ll also see four ways to replace named placeholders in a template, tested in PowerShell 7.6 and 5.1.

How does the -f format operator work in PowerShell?

The -f operator is PowerShell’s shortcut to .NET composite formatting, the same engine behind [string]::Format(). Each placeholder, called a format item, has this shape:

{index[,alignment][:formatString]}

The index is required and starts at 0. Alignment sets a column width, and the format string controls how a number or date looks. Both are optional.

Placeholders don’t have to be in order, and you can use one more than once:

'{1}, {0}' -f 'Maria', 'Lopez'
'{0}, {1} ({0} office)' -f 'Denver', 'CO'
[string]::Format('{0} + {1} = {2}', 2, 3, 5)

Output:

Lopez, Maria
Denver, CO (Denver office)
2 + 3 = 5

The last line shows the static method version. It gives the same result, so pick whichever reads better. If you only need to glue a few values together, you can also concatenate strings with + or -join.

Format numbers with -f: decimals, commas, currency and percent

Add a colon and a format specifier after the index. These are the ones I use most:

$total = 1234567.891
'{0:N2}' -f $total
'{0:C}' -f 19.5
'{0:P1}' -f 0.4567
'{0:F1}' -f $total
'{0:D5}' -f 42
'{0:X}' -f 255
'{0:#,0.00}' -f $total

Output:

1,234,567.89
$19.50
45.7%
1234567.9
00042
FF
1,234,567.89

Specifier	What it does	Example result
N2	Thousands separator, 2 decimals	1,234,567.89
C	Currency for the current culture	$19.50
P1	Multiplies by 100, adds %	45.7%
F1	Fixed decimals, no separator	1234567.9
D5	Zero-pads whole numbers to 5 digits	00042
X	Hexadecimal (whole numbers only)	FF

The digit after the letter is the precision. D and X only work on whole numbers. Custom patterns like #,0.00 work too, and {0:00000} zero-pads the same way D5 does.

Keep in mind that -f returns text, not a number. If you need a value you can still do math with, round to 2 decimal places with [math]::Round first.

Pad and align text in columns

The alignment part sets a field width. A positive number right-aligns the value and a negative number left-aligns it, padding with spa