Rounding Calculator
Round any number to decimal places or the nearest ten, hundred or thousand — with five rounding rules.
Reviewed by the WorldCalcs team · Methodology · Last reviewed: July 2026
Rounded value
3.14
Rounded 3.14159 to 2 decimal places (half up) = 3.14
What is a rounding calculator?
A rounding calculator takes a number and shortens it to a chosen level of precision — a set number of decimal places, or the nearest ten, hundred or thousand. Rounding keeps numbers readable and matches the precision you actually need: a price to two decimals, a measurement to one, a population to the nearest thousand. The result depends on two choices: where you round (the place value) and which rule you use to handle a value that sits exactly halfway. This tool lets you pick both, so you can see how the same number rounds under each common convention.
How rounding works
To round to a place value, look at the digit just to the right of it. If that digit is less than 5 you round down (keep the digit), and if it's more than 5 you round up. The interesting part is a tie — when the next digit is exactly 5 with nothing meaningful after it. Different rules break ties differently. "Round half up" sends ties away from zero, so 2.5 becomes 3. "Banker's rounding" (round half to even) sends ties to the nearest even digit, so 2.5 becomes 2 but 3.5 becomes 4 — this keeps large batches of rounded numbers from drifting upward. "Ceiling" always goes toward positive infinity, "floor" always toward negative infinity, and "truncate" simply drops the extra digits toward zero. This calculator also corrects for the way computers store decimals, so a value like 2.345 rounds to 2.35 as you'd expect, rather than 2.34.
Worked example
Round 3.14159 to two decimal places. The digit after the second decimal is 1, which is less than 5, so the number rounds down to 3.14. Round the same number to four decimal places and you look at the fifth digit, 9, which rounds the 5 up to give 3.1416. Ties show the difference between methods most clearly: 2.5 rounded to a whole number is 3 with "round half up" but 2 with banker's rounding, because 2 is the nearest even number. Rounding to place values above the decimal point works the same way — 1234.5 to the nearest ten is 1230. To control precision by counting meaningful digits instead of decimal places, see the significant figures calculator, and to write very large or very small rounded numbers compactly, see the scientific notation converter. For everyday percentage work, the percentage calculator and the average calculator pair well with rounding.
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Results are estimates and may contain errors — for general information only, not professional advice. Always verify before relying on them. Disclaimer
How to use
Enter the number, pick where to round it (decimal places, or nearest ten / hundred / thousand), and choose a rounding rule. Round half up is the everyday default; banker's rounding avoids upward bias across many values; ceiling, floor and truncate follow their usual mathematical meaning.
The tool corrects for floating-point representation errors, so a value like 2.345 rounds to 2.35 as the digits suggest.