Long Subtraction Calculator — Step-by-Step Column Subtraction
See every borrow in long subtraction: enter two whole numbers and get a step-by-step breakdown of each column — ones, tens, hundreds and beyond — showing exactly when and why borrowing happens.
503 − 278
Ones: 3 < 8 → borrow
Tens: 0−1 < 7 → borrow
Hundreds: (5−1) − 2
Difference
- 1
Minuend
503 - 2
Subtrahend
278 - 3
Difference
503 − 278 = 225
How does this calculator work?
Long subtraction works column by column right to left. If the top digit is smaller than the bottom digit, borrow 10 from the next column left and subtract 1 from that column. Repeat until all columns are done. Enter two whole numbers to see every step including borrows.
Formula
How this is calculated
Long subtraction aligns the two numbers on the right and works column by column from the ones place outward to the left. At each column, if the top digit (minuend digit) is greater than or equal to the bottom digit (subtrahend digit), they are subtracted directly. If not, the algorithm "borrows" 1 from the column to the left, effectively adding 10 to the current column and reducing the next column by 1 — this is also called "regrouping".
The borrow can cascade: if the column to the left has a 0, that column must also borrow from the column further left before it can donate. This chain of borrows is the part most children find tricky, and the step-by-step display shows each borrow explicitly so the logic is traceable.
This calculator enforces that the minuend ≥ subtrahend so the result is non-negative; if you enter numbers in the wrong order they are swapped automatically. Numbers up to 9,999,999 (seven digits) are supported.
Frequently asked questions
When the top digit in a column is smaller than the bottom digit, you take 1 unit from the column to the left (worth 10 of the current units) and add it to the current column. For example, in the tens column, borrowing adds 10 tens to the current column, turning a digit of 2 into an effective 12.
Each zero column cannot donate a borrow directly — it first borrows from the next column to its left, turning its 0 into a 9 (after lending one to the right) and propagating the borrow leftward. The step list shows each such cascade explicitly.
This calculator keeps results non-negative by always placing the larger number on top. For negative differences, negate the result: 278 − 503 = −225, which is −(503 − 278).
Also known as
TG we-Calculate Editorial Team. (2026). Long Subtraction Calculator — Step-by-Step Column Subtraction [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/long-subtraction-calculator
TG we-Calculate Editorial Team. "Long Subtraction Calculator — Step-by-Step Column Subtraction." TG we-Calculate. 2026. https://we-calculate.com/calculator/long-subtraction-calculator.
TG we-Calculate Editorial Team, "Long Subtraction Calculator — Step-by-Step Column Subtraction," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/long-subtraction-calculator
@misc{wecalculate_long_subtraction_calculator, title = {Long Subtraction Calculator — Step-by-Step Column Subtraction}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/long-subtraction-calculator}}, year = {2026}, note = {TG we-Calculate} }
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