Rounding Calculator - Round to Nearest Decimal Online
Round numbers to decimal places, significant figures, or the nearest 10, 100, or 1000. Also shows truncated, ceiling, and floor values.
How to use this calculator
👉 Fill in the boxes below and your answer appears instantly — no maths needed, we do it all for you! 🎉
In plain English — what does this do?
🔢 This tool does the maths for you! Just type in your numbers, and it gives you the answer right away. No need to count on your fingers or use a pen and paper.
The rounding calculator rounds any number according to your chosen method: decimal places, significant figures, or the nearest integer, 10, 100, or 1000. It also shows the truncated value, ceiling (round up), and floor (round down) for comparison.
Rounded Result
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Truncated
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Ceiling
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Floor
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What is Rounding Calculator - Round to Nearest Decimal Online?
The rounding calculator rounds any number according to your chosen method: decimal places, significant figures, or the nearest integer, 10, 100, or 1000. It also shows the truncated value, ceiling (round up), and floor (round down) for comparison.
How to use it
- 1️⃣ Enter the number you want to round.
- 2️⃣ Select the rounding method from the dropdown.
- 3️⃣ Enter the number of decimal places or significant figures if applicable.
- 4️⃣ Click Calculate to see the rounded result.
- 5️⃣ Compare with truncated, ceiling, and floor values shown below.
Formula
💡 See it in action — a real example
❓ Common questions
- What is the difference between rounding and truncating?
- Rounding adjusts the last kept digit based on the next digit (≥5 rounds up). Truncating simply drops all digits after the cutoff point, always rounding toward zero.
- What are significant figures?
- Significant figures are the meaningful digits in a number, starting from the first non-zero digit. For example, 0.00423 has 3 significant figures (4, 2, 3).
- What is ceiling vs floor rounding?
- Ceiling always rounds up to the nearest integer (e.g., 3.1 → 4, −3.1 → −3). Floor always rounds down (e.g., 3.9 → 3, −3.1 → −4). These are mathematical ceiling and floor functions.
- When should I round to significant figures vs decimal places?
- Use significant figures in scientific and engineering contexts where the precision of the measurement matters. Use decimal places in financial and everyday calculations.
- What is banker's rounding?
- Banker's rounding (round half to even) rounds 0.5 to the nearest even number to reduce cumulative bias. This calculator uses standard rounding (half up).