TRUNC Function in Microsoft Excel: Examples, Pitfalls & Compatibility
TRUNC in Microsoft Excel: discard digits toward zero at a selected decimal position without rounding up. Includes worked examples and application-specific cautions.
Verification status: Official documentation referenced; example outcomes independently reasoned or arithmetically checked where stated. Not executed in Microsoft Excel. How formula examples are checked
Quick answer: Use TRUNC in Microsoft Excel to discard digits toward zero at a selected decimal position without rounding up. The official TRUNC reference is the source for the function definition and platform-specific rules described below.
Syntax and arguments
=TRUNC(number, [num_digits])
number (required): The numeric input to truncate.
num_digits (optional): Decimal position to retain; the default is 0. Positive positions are to the right of the decimal point; negative positions are to its left.
Square brackets mark optional arguments; do not type those brackets into the example formulas. Examples use English function names, comma argument separators and decimal points. Adapt formula separators to your workbook settings, not punctuation inside quoted text.
When to use it
Use TRUNC when the written rule calls for discarding lower-order digits, not rounding to the nearest value. The default produces an integer toward zero, so it differs from INT on negative nonintegers.
Three worked examples
Each example is independent. Where input cells are listed, enter those values first; otherwise the formula is self-contained. Expected outputs are independently checked calculations or documented error expectations, not captured results from Microsoft Excel.
Example 1: Discard extra fractional digits
=TRUNC(12.987,2)
Expected result: 12.98.
The third decimal digit is discarded rather than increasing the second digit.
Example 2: Truncate a negative decimal
=TRUNC(-12.987,2)
Expected result: -12.98.
The result moves toward zero. It does not floor the value to -12.99.
Example 3: Discard tens and units
=TRUNC(5678,-2)
Expected result: 5600.
A position of -2 keeps the hundreds boundary toward zero and removes the lower whole-number digits.
Put it to work safely
Record the permitted decimal position beside the raw numeric value and compute a separate truncated result. Review both positive and negative records before replacing source values. A number format may display two decimals without applying the same value transformation; choose whether the task is presentation or an actual change to the value used by later formulas.
Common mistakes and fixes
A final digit does not round up. TRUNC discards the remaining digits. Use ROUND when the nearest value is required.
Negative values disagree with INT. TRUNC moves toward zero while INT floors. Neither is universally more correct; use the rule required by the calculation.
Negative places are misunderstood. A negative position removes low-order whole-number digits. It does not mean “retain a negative number of decimals” in the display.
Microsoft Excel-specific notes
Excel calls the optional precision argument num_digits and documents a default of zero. Its comparison with INT makes the signed-number distinction explicit. The cases here use clear decimal values rather than relying on undocumented coercion. See the vendor reference for the current definition.
Excel and Google Sheets comparison
The demonstrated toward-zero behavior and decimal-place selection have the same intended meaning in both references. Independently checked decimal examples do not establish bit-for-bit agreement near every floating-point boundary.
Compare the TRUNC guide for Google Sheets and its official documentation. Having a guide in both libraries establishes two documented references, not a certificate of identical behavior across releases, locales or file conversions.
Related guides
Evidence and testing scope
Editorial verification: Official references retrieved on 2026-10-12. The three worked cases are included in this release’s reproducible Python checking suite. It checks the stated arithmetic, calendar or text model and the expected documented error classification; it is not the Microsoft Excel calculation engine. No native application run, UI screenshot, maximum-size benchmark or cross-version certification is claimed. Review the editorial testing standards before relying on a formula in a critical workbook.