Enter two or more numbers to subtract them from left to right.
How to Use the Subtraction Calculator
Add or remove rows with the buttons under the list, and the calculator subtracts every number after the first from the one before it, left to right. The default three rows — 100, 30, 15 — work out to 100 − 30 − 15 = 55, shown underneath as a readable running calculation right alongside the final result.
Order isn't an arbitrary choice here the way it is for the Addition or Multiplication calculators sitting next to this one on the site. Addition and multiplication don't care which order the numbers go in — 3 + 7 and 7 + 3 land on the same total, same for 3 × 7 and 7 × 3. Subtraction breaks that rule outright: 10 − 3 comes to 7, but 3 − 10 comes to −7. Swap the first two entries in this list and the result changes, not just the order it's written in.
That's why the first row carries more weight than the rest — it's the starting value everything after it gets taken away from, not an interchangeable entry in a list.
Nothing stops the running total from going negative partway through, either. If the numbers being subtracted add up to more than the first one, the result comes out negative — that's a normal outcome here, not an error.
A running budget works the same way in practice: start with an amount, list every expense as its own row, and the result is whatever's left after all of them come out, in the exact order you subtract them.