Rounding Calculator
Round numbers to a specified number of decimal places with standard, up, and down rounding.
The Rounding Calculator rounds any number to your desired decimal places using three methods: standard rounding (half-up), ceiling (always up), and floor (always down).
Rounding Methods
- Standard (Half-Up): Rounds to the nearest value. If the next digit is 5 or more, round up; otherwise round down. Example: 3.145 → 3.15
- Round Up (Ceiling): Always rounds toward positive infinity. Example: 3.141 → 3.15
- Round Down (Floor): Always rounds toward negative infinity. Example: 3.149 → 3.14
When to Use Each Method
Standard rounding works for most everyday calculations and scientific measurements. Round up when you need to ensure a minimum (e.g., materials needed for construction). Round down for conservative estimates or when truncating data. Specify 0 decimal places to round to the nearest whole number.
Frequently Asked Questions
What does rounding to 0 decimal places do?
It rounds to the nearest whole number. For example, 3.7 rounds to 4 (standard), 4 (up), and 3 (down).
How does standard rounding handle exactly 0.5?
This calculator uses 'round half up' — when the digit to be dropped is exactly 5, it rounds up. So 2.5 rounds to 3, and 3.5 rounds to 4.
What is the maximum precision?
You can round to up to 15 decimal places, which is the practical limit of floating-point precision.