About the Armstrong Number Checker
An Armstrong number, also called a narcissistic number, is one that equals the sum of its own digits each raised to the power of the number of digits. The number 153 is one: 1³ + 5³ + 3³ = 1 + 125 + 27 = 153. This checker tests any number up to 40 digits and can also list every Armstrong number up to a limit of your choice, up to ten million. Type a number to check and, optionally, a limit for the list and the Armstrong numbers appears at once, with a few related figures underneath, and you can copy the result with one tap. The sums run in your browser, so nothing you enter is uploaded.
Updated October 2026
How to use the Armstrong Number Checker
- 1Enter a number to check and, optionally, a limit for the list.
- 2Pick the units or options from the menus if the Armstrong numbers tool offers them.
- 3Read the Armstrong numbers in the large result box.
- 4Look at the extra rows for related figures.
- 5Press Copy result to keep the answer.
When you need the Armstrong numbers
Armstrong numbers are a classic exercise in programming courses, where students write loops to find them. They are also a gentle way to explore digits and powers in recreational maths.
All single-digit numbers are Armstrong numbers trivially. There are only 88 in total in base 10, and the largest has 39 digits, so the search for them ends. The list for four digits is short, with only three.
How the Armstrong numbers is worked out
With d digits, add each digit raised to the power d. If the total equals the original number, it is an Armstrong number. The number 153 passes. So does 9,474: 9⁴ + 4⁴ + 7⁴ + 4⁴ = 6,561 + 256 + 2,401 + 256 = 9,474. Up to 10,000 the Armstrong numbers are 1 to 9, then 153, 370, 371, 407, 1,634, 8,208 and 9,474. The number 154 fails.
Every answer on this page comes from that one rule, so you can check any result by hand with a calculator. The figures shown underneath, such as other units, are conversions of the same answer.
- Check any number
- List up to 10 million
- Shows the power sum
Mistakes to avoid with Armstrong numbers
The list feature checks every number up to the limit, so a big limit takes a moment. The limit is capped at 10,000,000 to keep the page responsive. Enter digits only; spaces and commas are not accepted in the check box.
On phone and computer
On a phone, type into the boxes one after another and read the Armstrong numbers underneath; Copy result puts it on the clipboard for a message or a note. On a computer the inputs sit on the left and the answer on the right, so you can change one figure and watch the Armstrong numbers move. The armstrong number checker works the same on both. Numbers with special properties are fun to compare. Try Perfect Number Checker, Digital Root Calculator, Prime Number Calculator and Factorial Calculator for more number puzzles.
Features
- Single digits all qualify
- Only 88 exist
- Large lists take a moment
- Clear messages when the Armstrong numbers inputs make no sense
- Copy the result with one tap
- Private: nothing is uploaded
Frequently asked questions
How do I calculate Armstrong numbers?
With d digits, add each digit raised to the power d. If the total equals the original number, it is an Armstrong number. The number 153 passes. So does 9,474: 9⁴ + 4⁴ + 7⁴ + 4⁴ = 6,561 + 256 + 2,401 + 256 = 9,474. Up to 10,000 the Armstrong numbers are 1 to 9, then 153, 370, 371, 407, 1,634, 8,208 and 9,474. The number 154 fails.
What is the formula for Armstrong numbers?
With d digits, add each digit raised to the power d. If the total equals the original number, it is an Armstrong number. The armstrong number checker applies it exactly and rounds only the displayed answer to six significant figures.
Why are they called narcissistic?
Because each number is made from a function of its own digits, like looking at itself.
How many Armstrong numbers are there?
Exactly 88 in base 10.
What is the biggest one?
It has 39 digits: 115,132,219,018,763,992,565,095,597,973,971,522,401.
Is this armstrong number checker free and private?
Yes. It is free, needs no account and runs in your browser, so the numbers you type are not uploaded or stored.