Rounding Calculator
Free online rounding calculator to round numbers to the nearest whole number, decimal place, or significant figure. Supports multiple rounding modes including standard, ceiling, floor, and banker's rounding.
Enter Values
Enter the number you want to round
Select the type of precision
Number of places, sig figs, or the nearest value (e.g. 100)
Standard is most common; Banker's is used in finance
Result
Enter values above and click Calculate to see your result.
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Formula
Applies the selected rounding rule (Standard, Up, Down, or Half-to-Even) to the number at the specified precision level.
Worked Example
How Rounding Works
- Standard Rounding: Rounds to the nearest value. If the next digit is 5 or greater, round up; otherwise, round down.
- Ceiling (Up): Always rounds towards positive infinity, regardless of the next digit.
- Floor (Down): Always rounds towards negative infinity, effectively truncating decimals.
- Banker's Rounding: Rounds to the nearest even number when the next digit is exactly 5. This reduces cumulative rounding errors in large datasets.
Whether you are rounding for financial reports, scientific measurements, or everyday estimates, selecting the right mode and precision ensures your results are both practical and accurate.
You can also calculate changes using our Percentage Calculator, Scientific Calculator or Average Calculator.
Frequently Asked Questions
What is Banker's rounding and when is it used?
Banker's rounding (half to even) rounds to the nearest even number when the digit is exactly 5. For example, 2.5 rounds to 2 and 3.5 rounds to 4. It is used in finance, accounting, and statistics because it eliminates the upward bias of standard rounding across large datasets. IEEE 754 floating-point arithmetic uses this method by default.
How do significant figures differ from decimal places?
Significant figures count all meaningful digits starting from the first non-zero digit, regardless of the decimal point. Decimal places count only digits after the decimal. For 0.00456: there are 3 significant figures (4, 5, 6) but 5 decimal places. For 1200: there are 2 to 4 significant figures depending on context, but 0 decimal places.
How do I round to the nearest 10, 100, or 1000?
Select the "Nearest 10, 100, 1000" mode and enter the value. To round 12,345 to the nearest 100: the hundreds digit is 3, the next digit is 4 (less than 5), so round down to 12,300. To round 12,367 to the nearest 100: the next digit is 6 (5 or more), so round up to 12,400.
What is the difference between ceiling and floor rounding?
Ceiling (round up) always moves toward positive infinity: 3.2 becomes 4, and -3.8 becomes -3. Floor (round down) always moves toward negative infinity: 3.8 becomes 3, and -3.2 becomes -4. Standard rounding looks at the next digit to decide, while ceiling and floor ignore it entirely.
Why does rounding matter in science and engineering?
Measurements have limited precision. Reporting 3.14159 when your instrument only measures to 0.01 implies false accuracy. Rounding to the correct number of significant figures communicates the actual reliability of the data. In engineering, over-rounding can introduce errors that compound across calculations.
How do I round negative numbers?
Standard rounding works the same way: -2.5 rounds to -3 (away from zero) in half-up mode. In ceiling mode, -2.5 rounds to -2 (toward positive infinity). In floor mode, -2.5 rounds to -3 (toward negative infinity). In Banker's mode, -2.5 rounds to -2 (nearest even).
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