Rounding Calculator
Round any number to the nearest whole number, tenth, hundredth, ten, hundred, thousand and more — using half-up, half-down, banker's rounding, ceiling, floor, or truncation.
Frequently Asked Questions
How do you round a number to the nearest whole number, tenth, or hundredth?
Look at the digit immediately to the right of the place you are rounding to. If it is 5 or more, round the target digit up; if it is 4 or less, keep it and drop the rest. Examples: 3.14159 → 3 (nearest whole), 3.1 (nearest tenth), 3.14 (nearest hundredth). For tens/hundreds, the same rule applies to the left of the decimal: 1,847 → 1,850 (nearest ten) → 1,800 (nearest hundred).
What is banker's rounding (round half to even)?
When a value is exactly halfway (e.g. 2.5 or 3.5), banker's rounding rounds to the nearest even digit: 2.5 → 2, 3.5 → 4. Regular half-up rounding always pushes .5 upward, which introduces a small systematic upward bias when summing many rounded values. Banker's rounding cancels that bias, which is why it is the default in IEEE 754 floating-point arithmetic, Python's round(), and many financial systems.
What is the difference between rounding, ceiling, floor, and truncation?
Rounding goes to the nearest value by rule. Ceiling always goes up to the next multiple (3.01 → 4), floor always goes down (3.99 → 3), and truncation simply cuts off digits toward zero (−3.7 → −3, where floor would give −4). Ceiling is used for "how many containers do I need" problems; floor for "how many complete units fit"; truncation is common in programming integer conversion.
Why does rounding matter in real calculations?
Rounding too early compounds errors: rounding each line of an invoice before summing can differ from rounding the final total by several cents — which is why accounting standards specify when to round. In engineering and statistics, keep full precision through intermediate steps and round only the final result to the appropriate number of significant figures.