List every factor of a number and its prime factorization in your browser. Your numbers stay on your device.
Factor Calculator Online
List every factor of a number and its prime factorization in your browser. Your numbers stay on your device.
The Factor Calculator runs entirely in your browser. The numbers you type are computed locally and never leave your device or get uploaded to ArrayKit.
Factor Calculator lists every factor (divisor) of a positive whole number and breaks it down into its prime factorization. Type a number and it instantly shows all the factors from 1 up to the number itself, the unique prime factors with their exponents (like 2² × 3), and a clear flag for whether the number is prime or composite. It is useful for simplifying fractions, checking divisibility, finding a greatest common factor by hand, or just exploring number theory homework. Every result also includes a one-click copy of the full summary so you can paste it straight into notes or a worksheet. Built for students, teachers, and anyone factoring numbers quickly. Everything is computed locally in your browser.
Features
Lists every positive factor of a number in ascending order
Computes the full prime factorization with exponents (e.g. 2² × 3)
Flags whether the number is prime or composite at a glance
Shows the total factor count alongside the factor list
Copy the whole result summary or just the factor list with one click
Handles perfect squares, primes, and large composite numbers
Instant recalculation as you type, no page reload
Runs entirely in your browser with no numbers sent anywhere
How to use the Factor Calculator
Type a positive whole number into the input field
Review the full list of factors and the factor count
Check the prime factorization and the prime/composite badge
Copy the result summary or the factor list for your notes
Example
Input
12
Output
Factors: 1,2,3,4,6,12 · 2²×3
Common errors & troubleshooting
The Factor Calculator shows an error for a decimal like 4.5. — Factors are only defined for whole numbers. Round or re-enter the value as an integer, such as 4 or 5.
Entering 0 or a negative number produces an error. — Factorization is defined for positive whole numbers (1 or greater). Enter a positive integer.
A large number takes a moment to show all its factors. — Very large numbers have more divisors to check, but the calculation still completes locally in your browser without uploading the number.
The prime factorization looks unfamiliar for a large prime. — When a number is itself prime, its factorization is just the number with no exponent, matching the Prime badge shown above the result.
Frequently asked questions
What does the Factor Calculator do?
It takes a positive whole number and lists every factor (divisor) that divides it evenly, along with its prime factorization and whether the number is prime or composite.
How does the Factor Calculator find prime factorization?
It repeatedly divides the number by the smallest prime that evenly divides it until only 1 remains, then groups the primes into exponents, e.g. 12 becomes 2² × 3.
Can the factoring calculator tell me if a number is prime?
Yes. If a number has exactly two factors — 1 and itself — the Factor Calculator marks it Prime; otherwise it is marked Composite.
Does the divisors calculator handle large numbers?
Yes, it checks candidate divisors up to the square root of the number, so even large composite numbers resolve quickly without leaving your browser.
Is there a limit to how many factors the factor tree calculator can show?
No practical limit — every factor is listed and displayed as individual tags, and the total factor count is shown alongside the list.
Are the numbers I factor uploaded anywhere?
No. The Factor Calculator runs entirely in your browser. The numbers you type are never sent to a server and are not uploaded to ArrayKit.
Related tools
GCF Calculator — Find the greatest common factor of two or more integers with the steps.
LCM Calculator — Find the least common multiple of two or more integers with the steps.