Rounding Calculator
Free rounding calculator. Round any decimal to the nearest whole number, tenth, hundredth, thousandth, or significant figures.
Rounding Calculator
Comprehensive Guide & Practice
Master the mathematical principles, formulas, and step-by-step methods with worked examples and FAQs.
1. How to Round Numbers
Rounding is the process of replacing a number with a nearby number that is simpler to use or easier to work with. The standard rounding rule: if the digit being dropped is 5 or higher, round up; if it is 4 or lower, round down.
2. Rounding to Decimal Places
- Nearest whole number: Look at the first decimal digit. 3.7 → 4. 3.4 → 3.
- Nearest tenth: Look at the hundredths digit. 3.456 → 3.5. 3.441 → 3.4.
- Nearest hundredth: Look at the thousandths digit. 3.456 → 3.46. 3.454 → 3.45.
3. Significant Figures
Significant figures (or significant digits) measure the precision of a number. The rule: start counting from the first non-zero digit. 0.00456 has 3 significant figures (4, 5, 6). 3.1400 has 5 significant figures (including the trailing zeros after the decimal).
See also: Absolute Value | Scientific Notation | Algebra Basics