Round numbers to decimal places, significant figures, or nearest integers with detailed step-by-step explanations and multiple rounding options.
Enter Number & Rounding Type
Result
Enter a number to see rounding results
Rounding Rules
Basic Rule
• Look at the digit to the right of rounding position
• If ≥ 5: round up
• If < 5: round down
• Replace following digits with zeros
Decimal Places
• Count positions after decimal point
• 3.14159 → 3.14 (2 decimal places)
• Used in money, measurements
Significant Figures
• Count meaningful digits
• Start from first non-zero digit
• 0.00123 has 3 significant figures
• Used in scientific calculations
Place Value
• Round to specific place values
• Nearest 10, 100, 1000, etc.
• 1,234 → 1,200 (nearest hundred)
• Used for estimates, approximations
Examples
Example 1: Decimal Places
Round 3.14159 to 2 decimal places:
Look at 3rd decimal place: 1 (< 5, so round down)
Result: 3.14
Example 2: Significant Figures
Round 0.004567 to 3 significant figures:
First 3 significant digits: 4, 5, 6
Next digit is 7 (≥ 5, so round up)
Result: 0.00457
Example 3: Nearest Hundred
Round 1,234 to nearest hundred:
Look at tens digit: 3 (< 5, so round down)
Result: 1,200
Frequently Asked Questions
Look at the digit immediately to the right of where you want to round. If it's 5 or greater, round up. If it's less than 5, round down. This is called the 'round half up' method.
Tips
Enter the dimensions in the same unit for consistency.
Results update automatically as you type.
Use the unit selector to convert between different measurement systems.