Rounding Calculator
Round numbers to any place value or significant figures.
Rounded
3.14
Rounded up (ceiling)
3.15
Rounded down (floor)
3.14
Rounding error
0.00159
The half-up convention
Standard rounding sends digits 5–9 up and 0–4 down: 3.145 → 3.15 at two places. Financial systems sometimes use banker's rounding (half to even) so that up- and down-rounds cancel over many transactions.
Round late
Rounding intermediate results compounds error — 3.14 × 3.14 differs from π² by more than the final rounding would. Keep full precision through the calculation and round once at the end, to the precision your context justifies.
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