The Excel ROUNDDOWN function rounds a number toward zero to a set number of digits — it always pulls the value down in magnitude, effectively truncating extra digits.
Syntax
| Argument | Description | |
|---|---|---|
number | Required | The number you want to round down (toward zero). |
num_digits | Required | How many digits to round to. Positive = decimal places, 0 = nearest whole number, negative = left of the decimal (tens, hundreds, ...). |
How to use it
ROUNDDOWN uses the same (number, num_digits) syntax as ROUND but always rounds toward zero, discarding the rest of the digits no matter how large:
With num_digits set to 0, ROUNDDOWN behaves exactly like TRUNC — both simply drop the fractional part toward zero.
ROUNDDOWN vs INT: for negatives they differ. =ROUNDDOWN(-2.9, 0) is -2 (toward zero), but =INT(-2.9) is -3 (toward negative infinity).
Try it: interactive demo
Pick a ROUNDDOWN example to see the formula and its result.
Practice workbook
Frequently asked questions
Is ROUNDDOWN the same as TRUNC?
num_digits = 0 they're identical — both drop the decimals toward zero. They also share the same behavior at other digit counts, so the choice is mostly stylistic.Does ROUNDDOWN round negatives toward or away from zero?
=ROUNDDOWN(-2.9, 0) returns -2, the value closer to zero.How is ROUNDDOWN different from ROUND?
3.789 at 1 decimal becomes 3.8. ROUNDDOWN always pulls toward zero, giving 3.7.What does a negative num_digits do?
=ROUNDDOWN(1299, -2) rounds down to the nearest hundred = 1200.Master functions like this in one day
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