Arithmetic sequence calculator
Published On: 04/03/2026
Arithmetic Sequence Calculator
Generate an arithmetic sequence and calculate the n-th term and the sum of the first n terms. An arithmetic sequence adds a constant value (the common difference) each step.
Inputs explained:
• First term (a₁): the starting number in the sequence.
• Common difference (d): how much each term increases/decreases (can be negative).
• Number of terms (n): how many terms to generate and sum.
• Rounding: controls how many decimals appear in results.
• First term (a₁): the starting number in the sequence.
• Common difference (d): how much each term increases/decreases (can be negative).
• Number of terms (n): how many terms to generate and sum.
• Rounding: controls how many decimals appear in results.
Tip: If d is negative, the sequence decreases (example: 10, 8, 6, 4...).
Arithmetic Sequence Calculator — Description
The Arithmetic Sequence Calculator generates the terms of an arithmetic sequence and calculates both the n-th term and the sum of the first n terms. An arithmetic sequence is a list of numbers where the difference between consecutive terms is constant (the common difference).
Nth term: aₙ = a₁ + (n − 1)d
Sum: Sₙ = n/2 × [2a₁ + (n − 1)d]
Enter the first term (a₁), the common difference (d), and the number of terms (n). The calculator will output the full sequence, the n-th term, and the total sum—useful for algebra homework, SAT/ACT prep, and general math practice.