Syntax
ROUNDDOWN(number, num_digits)
| Parameter | Description |
|---|---|
| number | Parameter of the ROUNDDOWN function. |
| num_digits | Parameter of the ROUNDDOWN function. |
Examples
Truncate to cents
Formula
=ROUNDDOWN(15.6789, 2)
Returns 15.67. Drops everything past the second decimal without rounding up. Useful for tax calculations where partial cents are truncated.
Remove decimals
Formula
=ROUNDDOWN(9.99, 0)
Returns 9. Strips the decimal portion entirely, always rounding toward zero.
Round down to hundreds
Formula
=ROUNDDOWN(2876, -2)
Returns 2800. Negative digits truncate to the left of the decimal point.
Common Errors
#VALUE!
Happens when a non-numeric value is passed as the number argument.
#NUM!
Occurs in rare edge cases with extreme values.
Tips
Equivalent to TRUNC
For positive numbers, ROUNDDOWN(x, n) and TRUNC(x, n) give the same result. They differ only for negative numbers and edge cases.
Tax and financial truncation
Many tax systems truncate rather than round. Use ROUNDDOWN for IRS withholding tables and similar calculations where partial cents are dropped.
Conservative budgeting
When estimating revenue, ROUNDDOWN gives a conservative figure. When estimating costs, use ROUNDUP instead.
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