Subtraction Calculator
Subtract one number from another, or work through a list from left to right, with each step of the calculation written out.
How to use it
- Enter two numbers — the answer updates as you type.
- Switch to the list tab to work through many numbers at once, left to right.
- The working underneath shows the substitution so you can check it by hand.
Examples
| 25 − 17 | 8 |
| 100, 20, 5 | 75 |
Subtraction finds the difference between two numbers, or works through a running list left to right, each new number subtracted from the previous result. It's not commutative — order matters, which is the single most common source of sign errors when doing it by hand under time pressure.
Worked example — running a bank balance down
Starting balance 100, then withdrawals of 20 and 5 processed in order: 100, 20, 5 in list mode gives 100 − 20 = 80, then 80 − 5 = 75 — the running-list mode mirrors how a balance actually gets debited, one transaction at a time, rather than requiring the total to be subtracted in one step.
Questions people ask
Why is my answer negative?
Because the second number is larger than the first. Subtraction is not commutative — 8 − 25 is −17, not 17.
Is anything sent to a server?
No. Every calculation runs in your browser, so nothing you type is uploaded and the page keeps working offline once it has loaded.
Last updated 22 August 2026