Rounding Calculator
Round any number to the nearest whole number, decimal places, or significant figures using multiple rounding modes.
Inputs
Results
Rounding Methods
Round Half Up: Standard rounding — 2.5 → 3, 2.4 → 2. Ceiling: Always up — 2.1 → 3. Floor: Always down — 2.9 → 2. Truncate: Drop decimals — 2.9 → 2, −2.9 → −2. Significant figures preserve the most meaningful digits.
What is the Rounding Calculator?
The Rounding Calculator simplifies long decimals or large numbers by rounding them to a specific place value (e.g., nearest tenth, hundredth, or whole number). It is essential for bookkeeping, scientific data, and estimating.
How It Works (Rule)
The standard mathematical rule for rounding looks at the digit immediately to the right of your target place value. If that digit is 5 or greater, the target digit rounds up. If it is 4 or less, the target digit stays the same.
$$ 3.14159 \xrightarrow{\text{nearest hundredth}} 3.14 $$
The digit 1 is less than 5, so the 4 remains unchanged.
How to Use It
Enter the number you want to round. Select the place value you wish to round to (such as tenths, hundredths, or thousands). The calculator will instantly output the properly rounded number.