Rounding Calculator
Round numbers to decimal places, whole numbers, or significant figures with detailed explanations.
Rounding Calculator
2 decimal places
Result
Original Number
Rounded Result
Method
Explanation
Common Roundings
Whole number:123
To 1 decimal:123.5
To 2 decimals:123.46
To 3 decimals:123.457
To nearest 10:120
To nearest 100:100
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What is Rounding Calculator?
Rounding is a mathematical process of reducing the number of digits in a number while keeping its value close to the original. It's essential in mathematics, science, engineering, and everyday calculations where precision needs to be balanced with practicality.
Types of Rounding
- Decimal Rounding: Round to a specific number of decimal places (e.g., 123.456 → 123.46 to 2 decimal places)
- Whole Number Rounding: Round to the nearest ten, hundred, thousand, etc. (e.g., 1,234 → 1,200 to nearest hundred)
- Significant Figures: Round to a specific number of significant digits (e.g., 123.456 → 123 to 3 significant figures)
Rounding Rules
- Basic Rule: If the digit to be dropped is 5 or greater, round up; if less than 5, round down
- Halfway Cases: When the digit is exactly 5, round to the nearest even number (banker's rounding) or always round up (common rounding)
- Significant Figures: Count only meaningful digits, starting from the first non-zero digit
- Trailing Zeros: In whole numbers, trailing zeros may or may not be significant depending on context
Applications
- Financial: Currency calculations, tax computations, interest calculations
- Scientific: Measurement reporting, experimental data, statistical analysis
- Engineering: Tolerance specifications, manufacturing dimensions, safety margins
- Everyday: Price estimation, time rounding, grade calculations
Examples
Decimal: 3.14159 → 3.14 (to 2 decimal places)
Whole: 1,847 → 1,800 (to nearest hundred)
Significant: 0.004567 → 0.0046 (to 2 significant figures)
FAQ - Rounding Calculator
Rounding adjusts a number to the nearest value at a specified precision, following specific rules (round up if ≥5, down if <5). Truncating simply cuts off digits without considering their value. For example, 3.67 rounded to 1 decimal is 3.7, but truncated is 3.6.