Rounding Calculator
Round numbers your way, to any precision.
How to use
- 1 Type the number you want to round.
- 2 Set how many decimal places to keep.
- 3 Choose a rounding mode: nearest, up, down, ceil or floor.
- 4 Read the result and copy it if needed.
About Rounding Calculator
The Rounding Calculator rounds any number to the precision and rule you need, so you are never left guessing how a value will behave at a boundary.
Enter a number, choose how many decimal places to keep, and pick a rounding mode: nearest rounds to the closest value with halves going away from zero, up and down round by magnitude (away from or toward zero), and ceil and floor round toward positive or negative infinity respectively.
The result updates live and is ready to copy.
Rounding sounds simple but the details matter. “Round half up” and “round toward zero” disagree on negative numbers, and ceiling versus flooring flips depending on sign — getting the wrong rule can quietly distort totals, prices or measurements.
This calculator makes each rule explicit so you can see exactly what happens to your value, including tricky negative and half-way cases.
Everything is computed locally in your browser using standard floating-point arithmetic, with no data sent anywhere, so it works offline and keeps your numbers private.
It is handy for checking financial figures, preparing data for display, verifying spreadsheet behaviour, or simply settling which rounding mode a piece of code should use before you write it.
FAQ
How are halfway values handled?
In “nearest” mode, halves round away from zero, so 2.5 becomes 3 and −2.5 becomes −3. Other modes apply their own rule consistently.
What is the difference between “down” and “floor”?
“Down” truncates toward zero, so −2.9 becomes −2. “Floor” rounds toward negative infinity, so −2.9 becomes −3. They agree for positive numbers.