Rounding Calculator

Rounding looks trivial until the half appears. 2.34 to one decimal place - obviously 2.3. But 2.35? The half sits exactly between the digits, and the rule you choose decides the result - which is why financial standards use banker's rounding, classrooms teach "round half up", and calculators do a third thing. Add significant figures - where leading zeros are not digits but trailing ones are - and the simple idea turns genuinely subtle.

Rounding Calculator makes the whole decision visible. Round to any number of decimal places or significant figures, with five strategies including half-even and half-away-from-zero. The tool marks the digit being rounded and the deciding digit, shows the digit-remains rule in action, and explains every result. No rounding decision is a guess anymore.

• Decimal places or significant figures: Both systems supported.
• Five rounding strategies: Half up, half down, half away, half even, half to zero.
• The decision shown: The rounding digit and deciding digit are marked.
• Place value preserved: The digit-remains rule explained.
• Negatives handled: Each strategy applied correctly to the sign.
• Instant results: Live as you type or change settings.
• Copy or download: Results ready for documents.
• Free and private: Everything runs in your browser; nothing is uploaded.

1. Enter the number - decimals and negatives both work.
2. Choose the system - decimal places or significant figures.
3. Set the count - how many places or digits to keep.
4. Pick the strategy - important only at exact halves.
5. Read the result with the step-by-step explanation.
6. Copy or download it for your work.

Example 1 - The classic. Round 3.14159 to 2 decimal places: the deciding digit is 1 (below 5), so the answer is 3.14.

Example 2 - The half. Round 2.35 to 1 decimal place: 2.4 with half up, 2.4 with half away, 2.4 with half even - and 2.3 with half down and half to zero. The tool shows why each differs.

Example 3 - Significant figures. Round 0.00314159 to 3 significant figures: 0.00314 - the leading zeros are placeholders, not digits.

Example 4 - Banker's rounding. Round 2.5 and 3.5 to whole numbers with half-even: both become 2 and 4 respectively, keeping sums unbiased.

Example 5 - Digit remains. Round 2499 to 2 significant figures: 2500 - the trailing zeros stay as placeholders, and the explanation shows why they cannot be dropped.

• Every strategy: Five ways to break the tie, one tool.
• Both systems: Decimal places and significant figures.
• Transparent decisions: The deciding digit is always shown.
• Standards-aware: Banker's rounding for financial work.
• Negatives correct: Strategy applied honestly to the sign.
• Free and private: Runs entirely in the browser with nothing uploaded.