Rounding Calculator
Round any number to decimal places, significant figures, or the nearest integer — with clear step-by-step explanations.
Rounding Calculator – Master Number Rounding
Rounding is the process of reducing the precision of a number while keeping it close to its original value. It's used in science, finance, engineering, and everyday calculations to simplify numbers and reduce complexity.
Rounding Rules
Standard Rounding (Half-Up)
The most common rounding rule: if the digit being dropped is 5 or greater, round up the preceding digit. If it's less than 5, round down (keep the preceding digit unchanged). Example: 3.45 rounded to 1 decimal = 3.5; 3.44 rounded = 3.4.
Rounding to Decimal Places
Count the desired number of digits after the decimal point, examine the next digit, and apply the standard rule. Popular in currency (2 decimals), scientific data (3–6 decimals), and percentages.
Rounding to Significant Figures
Significant figures count meaningful digits starting from the first non-zero digit. Used extensively in science — 0.004567 rounded to 3 sig figs = 0.00457.
Rounding to Place Value
Round to the nearest ten, hundred, thousand, etc. Useful for estimation, budgeting, and population figures. Example: 47,382 rounded to the nearest thousand = 47,000.
Frequently Asked Questions
What is banker's rounding?
Banker's rounding (round half to even) rounds 0.5 to the nearest even number to avoid systematic bias. 2.5 → 2, 3.5 → 4. Our calculator uses standard half-up rounding.
How many decimal places should I use?
Use 2 for money, 1–3 for measurements, 3–6 for scientific data. Always match the precision of your source data.