How to Round Numbers
Rounding simplifies a number to a specified precision. The standard rounding rule: if the next digit is 5 or higher, round up; otherwise round down.
Step-by-step
- Enter the number you want to round.
- Enter how many decimal places to keep (0 rounds to a whole number).
- The calculator applies standard rounding rules.
Worked example
Round 3.14159 to 2 decimal places: Look at the third digit (1). Since 1 < 5, round down → 3.14. Round 3.1459 to 2 places: Third digit is 5, so round up → 3.15.
Common rounding scenarios
- Currency: round to 2 decimal places (e.g., $19.99)
- Percentages: round to 1 decimal place (e.g., 33.3%)
- Whole numbers: round to 0 decimal places (e.g., 42)