Rounding & precision
To decimals and significant figures
Number
Results
Standard: 3.14
Banker's: 3.14
Floor/ceil: 3.14 / 3.15
Truncate: 3.14
Significant (3): 3.14
Rules
- Round half up: digit ≥5 rounds up, <5 rounds down
- Banker's rounding: exactly .5 goes to even (less bias)
- In physics, count significant figures, not decimals
- Rounding error ≤ half of the last kept digit
Significant figures: 0.00340 has 3 sig figs (3, 4, 0). Leading zeros don't count, trailing after the decimal do.