Rounding Calculator
Rounding trims a number to the precision you actually need — money to hundredths, measurements to tenths, populations to thousands. Choose the target place and this calculator rounds using the standard “half up” rule.
Results
Formula
How to use this calculator
- Enter the number.
- Choose how precise the result should be.
- Press Calculate — trailing zeros are kept so the precision is visible.
Worked example
Round 2.71828 to the nearest hundredth.
- The third decimal is 8, which is 5 or more.
- Round the hundredths digit (1) up to 2.
Result: 2.71828 rounds to 2.72.
Frequently asked questions
What is round-half-up?
When the discarded part is exactly half a unit (like 2.5 or 0.125 to two places), the value rounds up. It is the convention taught in most classrooms; some software uses “banker’s rounding” instead, which rounds ties to even.
How do I round to significant figures instead?
Significant figures count digits from the first non-zero digit rather than places after the decimal. Choose the custom decimal-places mode and count from your first significant digit for an equivalent result in most cases.
Why keep trailing zeros, like 2.70?
A trailing zero communicates precision: 2.70 means the value is known to the hundredth, while 2.7 only claims the tenth.
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