Rounding Calculator

Round numbers to any decimal place, significant figure, or nearest integer.

Rounding Calculator

Rounded to 2 decimal places

3.14

Ceiling (↑)

4

Floor (↓)

3

Truncated

3

Rounding Calculator Formula & How It Works

Round half-up: if digit ≥ 5, round up; else round down
  • Standard: round half away from zero (most common)
  • Ceiling (round up): always round up to next integer
  • Floor (round down): always round down
  • Significant figures: count from first non-zero digit

Standard rounding: look at the digit immediately after the target place. If ≥ 5, round up; if < 5, round down. For significant figures, count from the first non-zero digit. '3.14159' rounded to 3 sig figs = '3.14'. '0.00456' rounded to 2 sig figs = '0.0046'.

Rounding Calculator FAQs

What is the rule for rounding?

Look at the digit one place to the right of where you're rounding. If it's 0–4, keep the target digit unchanged (round down). If it's 5–9, add 1 to the target digit (round up). Drop all digits after the target place.

What is the difference between rounding and truncating?

Rounding uses the digit to the right to decide whether to increase the last kept digit. Truncating simply drops all digits after the target place with no adjustment. 3.78 truncated to 1 decimal = 3.7; rounded = 3.8.

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