Enter a number and choose decimal places or significant figures to round to.
How to Use the Rounding Calculator
Choose decimal places or significant figures with the mode toggle before entering the number — the two modes round differently enough that picking the wrong one gives a technically-wrong-for-your-purpose answer.
Decimal places and significant figures answer different questions, and mixing them up is the main way rounding goes wrong. Decimal places count digits after the point; significant figures count meaningful digits starting from the first non-zero one, wherever the point happens to fall. 0.004520 has six decimal places but only four significant figures (4, 5, 2, 0) — and rounding Earth's radius, 6,378,000 meters, to "2 decimal places" is meaningless, while rounding it to 3 significant figures (6,380,000) says something real about measurement precision.
This Rounding Calculator handles both modes. The rule underneath is standard "round half up": look at the digit right after your cutoff, and if it's 5 or more, the last kept digit rounds up.
3.14159 rounded to 2 decimal places = 3.14Worth knowing this isn't banker's rounding (round-half-to-even), which some financial software uses specifically to avoid systematic upward drift across many roundings. This tool sticks with the version taught in school, where 0.5 always rounds up.