Banker's rounding calculator (round half to even)
It is the default in IEEE 754 and in the round functions of Python and .NET, and it reduces bias when many rounded values are added.
Loading the tool…
Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter number and decimal places.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
If the dropped part is more than half, round up; if less, leave it; if exactly half, pick whichever makes the last kept digit even.
Example
Inputs: Number = 2.5, Decimal places = 0. Result: Banker's rounding: 2; Exact tie?: Yes, exactly halfway.
2.5
2
Limits and caveats
- It works on the digits you typed; software may see 2.675 as slightly less because of binary storage and give a different answer.
- It differs from normal rounding only on exact ties.
Questions about this tool
Why does round(2.5) return 2 in Python?
Python uses banker's rounding, so a tie goes to the even digit, and 2 is even.
Why is it called banker's rounding?
It does not push every half upward, so no small upward drift builds up when thousands of amounts are rounded and added.
Is 2.51 a tie?
No. The dropped part 0.51 is more than half, so both methods give 3.