Math
Arithmetic Sequence Calculator
Find the nth term and the sum of the first n terms of an arithmetic sequence.
Formula
Nth term = a1 + (n − 1) × d. Sum of first n terms = n ÷ 2 × (2 × a1 + (n − 1) × d).
How it works
Enter the first term, the constant difference, and n. The calculator gives both the nth term and the total of the first n terms.
FAQs
What does the Arithmetic Sequence do?
It takes the values you enter and works out the arithmetic sequence for you, showing the result straight away.
What should I enter?
Enter ordinary numbers in the boxes above. If a value does not make sense for this calculation, the page will ask you to check it instead of showing a wrong answer.
Can I use the result for homework or everyday maths?
Yes. It is a general-purpose maths helper; for exam or professional work, still check the steps against your own working.