What is the Arithmetic Sequence Calculator?
Find the nth term and the sum of an arithmetic sequence.
Enter first term, common difference and number of terms and the Arithmetic Sequence Calculator returns nth term, sum of n terms and first terms. Results update as you type, and nothing you enter leaves your device.
How it is calculated
aₙ = a + (n − 1)d
Sₙ = n ÷ 2 × (2a + (n − 1)d)
How to use it
- Enter first term.
- Enter common difference.
- Enter number of terms.
- Read nth term in the results panel. It updates as you type.
- Change any value to compare scenarios, or use Share to send the result as a link.
Worked example
Common questions
What formula does the Arithmetic Sequence Calculator use?
It uses: aₙ = a + (n − 1)d; Sₙ = n ÷ 2 × (2a + (n − 1)d).
What do I need to use the Arithmetic Sequence Calculator?
You need first term, common difference and number of terms. Sensible starting values are filled in so you can see how it works straight away.
Is the Arithmetic Sequence Calculator free, and is my data stored?
It is free with no sign-up. The calculation runs in your browser, so the values you enter are not sent to or stored on our server.