Arithmetic Sequence Calculator
Find the nth term and the sum of the first n terms of an arithmetic sequence.
Calculate
Enter your values below.
Result
nth term
0
Sum of first n terms
0
Formula used
aₙ = a₁ + (n−1)d
Sₙ = n/2 × (2a₁ + (n−1)d)
Example: First term 3, difference 5, n=10 → 10th term = 48, sum = 255.
How to use this calculator
- Enter First term (a₁), Common difference (d), Term number (n).
- Press Calculate to see your result instantly.
FAQ
Frequently asked questions
What is an arithmetic sequence?
A sequence where each term increases (or decreases) by the same fixed amount, called the common difference.
Can the common difference be negative?
Yes — a negative difference produces a decreasing sequence.
What does 'nth term' mean?
It's the value at a specific position n in the sequence.
How is the sum formula derived?
It averages the first and last term of the range, then multiplies by the number of terms.