Math & Stats

Rounding Calculator

Round any number to the nearest whole, ten, hundred, thousand, decimal place, or use round up (ceiling) and round down (floor) modes.

Rounding Calculator

Number

Round to

Mode

Method

How this calculator works

To round to a place value p: result = mode(value / p) × p, where mode is round, ceil (up) or floor (down). For decimal places n: result = mode(value × 10ⁿ) / 10ⁿ.

FAQ

Frequently asked questions

How does rounding work?

Rounding replaces a number with a nearby simpler value at a chosen place. With 'round half up', digits 0–4 round down and 5–9 round up. For example 2.47 rounded to one decimal place is 2.5.

What is the difference between round, ceil and floor?

Round goes to the nearest value; ceiling (ceil) always rounds up to the next value; floor always rounds down. So 2.3 rounds to 2, ceils to 3, and floors to 2.

How do I round to the nearest ten or hundred?

Divide by the place value, round to the nearest whole number, then multiply back. 1,347 to the nearest hundred is 1,300; to the nearest ten it is 1,350.

What is banker's rounding?

Banker's rounding (round half to even) rounds a trailing 5 to the nearest even digit to reduce bias over many operations. This calculator uses standard round-half-up by default.

Can I round to a set number of decimal places?

Yes — choose 'decimal places' and enter how many decimals you want. The calculator rounds the number to exactly that precision.