Long Multiplication Calculator
Multiply two whole numbers with step-by-step long multiplication, showing each partial product the way it is taught in school.
Last reviewed by the Radiatus Cloud team
Multiply two numbers the long way, with each partial product shown step by step.
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Long multiplication, step by step
Long multiplication is the standard written method for multiplying multi-digit numbers by hand. This calculator works through it the same way it is taught in school: it multiplies the first number by each digit of the second number in turn, shifting each partial product to the correct place value, then adds the partial products to reach the final answer. Seeing every step makes it a useful aid for learning and for checking homework rather than just getting the result.
Each line shows which digit is being used, the place value it occupies, and the partial product it contributes, so the logic of carrying and place value is clear.
Learning multiplication
Understanding long multiplication builds number sense and underpins later topics like polynomial multiplication and the distributive law. Students, parents helping with homework, and teachers preparing examples all benefit from a worked breakdown rather than a single answer. The method also shows why a two-digit multiplier produces two rows to add, a three-digit multiplier three rows, and so on.
The calculator handles negative numbers by multiplying the digits and applying the correct sign at the end. Inputs are treated as whole numbers, which is how the written method is normally practised. All calculation runs locally in your browser.
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Frequently Asked Questions
What is long multiplication?
It is the written method of multiplying each digit of one number by the other, shifting by place value, and adding the partial products to get the answer.
Why show partial products?
The partial products reveal how place value and carrying work, which helps students understand and check the method rather than memorising the answer.
Does it handle negative numbers?
Yes. It multiplies the absolute values digit by digit and applies a negative sign to the result when exactly one input is negative.
Can I multiply decimals?
The written method shown here works on whole numbers. Multiply the digits as integers first, then place the decimal point in the result.
Is there a size limit?
Inputs up to around one billion are supported, which keeps the step-by-step layout clear and the arithmetic exact.
Privacy & Security
Everything runs in your browser; nothing is uploaded.
How to Use
Enter two whole numbers to see the long multiplication worked out.
Disclaimer: This tool is provided "as is" without warranty of any kind. Results are for educational and utility purposes.
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