Summary

The Excel TRUNC function removes digits from a number by truncation rather than by rounding. It cuts the number at the specified point and discards everything beyond that point.

This makes TRUNC appropriate when the worksheet must preserve a strict lower-precision version of a value without letting rounding push the result upward or downward. The function is especially useful when you need to separate integer and fractional components or control decimal precision without applying any rounding rule.

Syntax

=TRUNC(number, [num_digits])

Microsoft documents one required argument and one optional argument. number is the value to truncate, and num_digits controls where the truncation occurs. If the second argument is omitted, Excel truncates to an integer.

Arguments

• number - [required] The value to truncate.
• num_digits - [optional] The number of digits to keep. If omitted, Excel uses 0.

TRUNC vs Related Functions

Using TRUNC

TRUNC is useful when the worksheet should retain only a specified portion of a numeric value and discard the rest without interpretation. In contrast to ROUND, there is no midpoint rule and no directional bias. The discarded digits simply cease to participate in the result.

This is especially useful when the fractional part needs to be isolated later. A decimal duration, for example, can be split into a whole component and a residual component by subtracting the truncated value from the original. That gives TRUNC a structural role in decomposition formulas, not just in numeric presentation.

It also matters with negative values. TRUNC moves toward zero, which means it behaves differently from INT for negative numbers. That difference becomes important in financial adjustments, signed variances, and data transformations where the direction of the cutoff has to be explicit.

Example 1 - Remove the Decimal Portion

This is the default behavior when the second argument is omitted.

=TRUNC(B1)

If B1 contains 5.99, the result is 5. No rounding rule is applied. The decimal portion is simply removed.

Example 2 - Keep Two Decimal Places Without Rounding

The optional second argument makes TRUNC more flexible than simple integer extraction.

=TRUNC(B2,2)

If B2 contains 3.14159, the result is 3.14. Unlike ROUND, the discarded digits do not affect the retained digits.

Example 3 - Truncate a Negative Number Toward Zero

This is where TRUNC differs from INT most clearly.

=TRUNC(B3,0)

If B3 contains -6.9, the result is -6. The value moves toward zero. By contrast, INT(-6.9) would return -7.

Example 4 - Extract the Minutes from Decimal Hours

TRUNC is useful for splitting a decimal value into components.

=(B4-TRUNC(B4))*60

If B4 contains 2.75, TRUNC returns 2. The remaining fraction is 0.75, and multiplying that by 60 converts it into 45 minutes.

TRUNC can also operate to the left of the decimal point when num_digits is negative. That makes it possible to truncate at tens, hundreds, or larger place values without invoking a rounding rule.

• TRUNC removes digits rather than rounding them.
• It moves toward zero, which matters for negative values.
• Negative digit arguments shift the truncation point left of the decimal.

Conclusion Recap

• Summary: TRUNC removes digits without rounding.
• Main use: Precision cutoffs and decomposition of whole versus fractional components.
• Key distinction: It differs from INT when negative numbers are present.
• Precision control: The optional second argument determines where the cut occurs.
• Function choice: Use TRUNC when the rule is "discard excess digits, do not round."