Rounding Calculator
Round any number to a specified decimal places, significant figures, or to the nearest integer, 10, 100, or 1,000.
Instant results with explanation.
Decimal Places vs Significant Figures Decimal places count digits after the decimal point. 3.14159 rounded to 2 decimal places = 3.14
Significant figures count all meaningful digits from the first non-zero digit. 3.14159 rounded to 3 significant figures = 3.14 0.00314159 rounded to 3 significant figures = 0.00314
Standard Rounding Rules (Half-Up) If the digit being dropped is less than 5, round down (truncate). If the digit being dropped is 5 or more, round up. Example: 2.345 rounded to 2 decimal places = 2.35 Example: 2.344 rounded to 2 decimal places = 2.34
Banker’s Rounding (Half-Even) A variant used in finance and statistics to reduce cumulative bias. When the dropped digit is exactly 5 (with nothing after), round to the nearest even digit. 2.345 → 2.34 (4 is even) 2.355 → 2.36 (6 is even) This calculator uses standard half-up rounding (JavaScript’s default behavior).
Rounding to Powers of 10 To round to the nearest 10: divide by 10, round to integer, multiply by 10. To round to the nearest 100: divide by 100, round, multiply by 100. Example: 1,234 rounded to nearest 100 = 1,200
Common Use Cases Decimal places: money (2 places), measurements, scientific data Significant figures: scientific notation, engineering tolerances Nearest 10/100/1000: population estimates, financial summaries, quick approximations