Math & Algebra Tool
Rounding Calculator
Round numbers to significant figures.
Σ The Formula
Round to n decimal places or significant figures
Real World Examples
Decimal Places
3.14159 to 2 places → 3.14
Whole Number
47.6 → 48
Significant Figures
12345 to 2 sig figs → 12000
Nearest 10
87 → 90
# About This Calculator
Rounding is the process of simplifying a number by keeping its value close to what it was but making it easier to read or use.
Common methods include:
• Standard (Half Up): If the next digit is 5 or more, round up. Otherwise, round down.
• Decimal Places: Limiting digits after the dot (e.g. currency to 2 places).
• Significant Figures: Keeping only the most meaningful digits.
This tool allows precise control over how you want to round your numbers for math homework, financial reports, or scientific data.
How To Use
- Enter the Number to round.
- Enter the target Precision (e.g., 2 for two decimal places).
- Select the Mode (Decimal Places or Significant Figures).
- Click Round.
Frequently Asked Questions
What is the rule for rounding 5?+
In standard 'Half Up' rounding, a 5 rounds UP. So 2.5 becomes 3. (Note: bankers sometimes use 'Round to Even' for 5s to reduce bias).
What is truncating?+
Truncating simply cuts off extra digits without looking at them. 2.9 truncated to a whole number is 2, whereas rounded it would be 3.
Difference between Sig Figs and Decimals?+
Decimal places count digits AFTER the point. Sig Figs count ALL meaningful digits from the first non-zero digit.
Why do we round?+
To make numbers easier to communicate and understand, or because the extra precision is experimental noise/error.
What is Floor and Ceiling?+
Floor always forces rounding DOWN (3.9 -> 3). Ceiling always forces rounding UP (3.1 -> 4).
Is Rounding Calculator free to use?+
Yes, Rounding Calculator on Matheric is completely free to use. We believe in accessible education and utility for everyone.