Long Multiplication Calculator
Multiply two whole numbers and see every step.
Shows each partial product with its place value, the shifted rows, and the final total added up.
Long multiplication is the method everyone learns for multiplying numbers too big to do in your head: break the second number into its digits, multiply the first number by each one, shift each result into its column, and add the stack up. It is worth understanding rather than memorising, because the same logic sits underneath the way computers and spreadsheets multiply.
Take 324 times 27. You multiply 324 by the 7 in the ones place to get 2,268. Then you multiply 324 by the 2, but that 2 is really 20, so the partial product is 6,480, not 648. That shift, the reason the second row slides one place to the left, is where most mistakes happen. Add 2,268 and 6,480 and you have 8,748. This calculator lays out every partial product with its place value spelled out, so you can see exactly where each row comes from and check your own working against it.
It handles negative numbers by multiplying the digits and then applying the sign at the end, since a negative times a negative is positive and a negative times a positive is negative. Whole numbers only, because long multiplication is a whole-number method; with decimals you multiply as if there were no point and place it back afterward.
This is a teaching tool as much as a calculator. If you are helping a child who is stuck on the carrying step, the row-by-row breakdown shows the part the textbook usually compresses into a single answer. Enter two whole numbers and you get each partial product, its shifted place value, and the final total.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.