PI gives you π inside formulas so you can calculate a circle’s circumference, a circle’s area, or angular quantities without typing a rounded constant. For a radius of 3, the formula =2*PI()*3 has an independently calculated expected result of approximately 18.849556. The result is not an observed Calligra execution.

=PI()

No arguments. There is no input radius argument inside PI: multiply PI’s result by the radius outside the parentheses. Calligra’s Trigonometric section documents PI() as a floating-point constant. It shows PI() ≈ 3.141592654 and does not document an optional parameter. Use the displayed decimal format to control the visible rounded result; do not replace the function with a manually rounded 3.14 when precision matters.

Evidence and scope: The official KDE function handbook and the source registry pinned to Calligra 26.08.2 (released 2026-10-08) were consulted on 2026-10-11. The registry confirms inclusion in the shipped source module, not that every operating-system package has the same functions enabled. KDE’s Calligra Sheets release page currently lists 26.08.2. The main documented installation environment is Linux, using a distribution package or Flatpak; Windows availability was not established for this review. These examples have not been entered or run in a native Calligra Sheets application.

Formula-entry conventions: Start a cell formula with =. Calligra’s English handbook writes multiple parameters with semicolons, as in IF(test;true_value;false_value); none of this function’s own calls takes multiple arguments except where explicitly shown in a composite formula. Locale-dependent decimal symbols and formula separators can differ: confirm them in the installed Insert → Function interface. Numeric constants in tables below use a decimal point for the English-locale example.

Enter the following data in a new worksheet. Row 1 contains headings, column B the radius, and columns C/D formulas. Length units may be centimetres, metres, etc.; keep them consistent.

The column C and D numbers are independently calculated values rounded here to six decimals. Actual on-screen digits depend on the installed version and cell formatting.

Steps: Type the five radii into B2:B6. Enter =2*PI()*B2 in C2 and copy/fill down to C6. Enter =PI()*B2^2 in D2 and copy/fill down to D6. For Circle C, circumference is 2 × π × 2.5 ≈ 15.707963 and area is π × 2.5² ≈ 19.634954. If your expected values differ, check whether the radius and diameter have been confused.

If E2 contains the count of full revolutions (for example 0.25), use:

=2*PI()*E2

The expected angular displacement is π/2 ≈ 1.570796327 radians for 0.25 revolutions. A full revolution is 2π radians. To flag a nonpositive radius rather than silently using it, enter:

=IF(B2>0;PI()*B2^2;"Check positive radius")

For B2=3, the expected area is 28.27433388; for B2=-3, the formula is expected to return the message. This illustrates IF-based input validation; see the existing IF function guide. The IF syntax is taken from the same KDE handbook, not from an app test.

• Missing parentheses: =PI is not the documented syntax; use =PI().
• Wrong radius/diameter: If B2 holds diameter, circumference is =PI()*B2, and area is =PI()*(B2/2)^2.
• Degree/radian confusion: PI supplies a number, not automatic angle conversion. For 180°, the radian equivalent is π. Do not feed a degree value to a trigonometric function expecting radians without conversion.
• Different displayed decimals: Compare to the expected rounded values at the same number of decimal places; cell formatting does not increase precision.
• Unexpected errors: Check the leading equals sign, unmatched parentheses, accidental text values, and number formatting. An error code was not observed in Calligra for this guide.
• Misleading decimal precision: π is irrational; a spreadsheet stores a finite approximation, not the entire infinite decimal expansion.

The official Microsoft Excel PI documentation and LibreOffice Calc mathematical-functions reference both document PI() without arguments. The mathematics of the example is transferable, but exact last-place precision, decimal punctuation, formatting and spreadsheet UI are not guaranteed identical. Calligra’s English handbook writes multi-argument expressions with semicolons. Always verify a transferred workbook’s formulas in the destination application.

PI is often used with sine, cosine, RADIANS, and DEGREES (all listed in the KDE function chapter). Related new tutorials may be under review rather than live. The site’s already-established IF guide explains the validation expression above; do not assume the new PI page is currently published.

• Calligra Sheets — function documentation
• KDE function handbook
• LibreOffice Calc mathematical-functions reference
• Pinned Calligra 26.08.2 trigonometric function registration

Verification status: Official documentation checked; example outcomes were independently reasoned or arithmetically checked where applicable. Not executed in Calligra Sheets.

• No genuine Calligra Sheets screenshots are included; this guide does not use mock application images.