Rounding Calculator – Guide & Formulas
Round any decimal or whole number to the nearest integer, tenth, hundredth, thousandth, or custom power. Supports half up, half down, and ceiling.
Instantly round numbers using multiple professional mathematical criteria. Select custom decimal places or specific significant digits and compare various rounding modes.
Key Takeaway
Use the free Rounding Calculator to round any decimal or whole number to the nearest integer, tenth, hundredth, thousandth, or custom power. supports half up, half down, and ceiling. Get instant results with step-by-step explanations.
How to Use the Rounding Calculator
- Enter the number you want to round.
- Select your rounding precision (tenth, hundredth, nearest thousand, etc.) or custom decimal places.
- Choose your preferred rounding mode (Half Up, Half To Even, Floor, Ceiling).
The Formula
Variable Definitions
- x: The original unrounded decimal value
- d: The number of decimal digits to keep
Rounding 3.456 to the Nearest Hundredth
Apply standard half-up rounding to a decimal.
- Step 1: Identify the digit in the hundredths place: 5 (in 3.456).
- Step 2: Look at the digit to its immediate right: 6.
- Step 3: Since 6 is 5 or greater, round the hundredths digit up: 5 becomes 6.
- Step 4: The rounded number is 3.46.
Frequently Asked Questions
What is Round Half to Even (Banker's Rounding)?
Banker's Rounding rounds half-way numbers to the nearest even digit (e.g., 2.5 rounds to 2, but 3.5 rounds to 4). This minimizes cumulative statistical bias in large datasets.
What is the difference between truncate and floor?
Truncating simply drops all digits past the decimal point without changing the value. Floor rounds downward toward negative infinity (e.g., floor of -3.1 is -4, while truncate of -3.1 is -3).
How does rounding affect precision?
Rounding reduces numeric precision but simplifies values, making them much easier to communicate and display in charts, prices, or receipts.