Number Sequence Calculator | Arithmetic, Geometric & Fibonacci

Number Sequence Calculator

Calculate arithmetic, geometric, and Fibonacci sequences. Find the nth term, sequence sum, and generate sequences.

Arithmetic Sequence
Geometric Sequence
Fibonacci Sequence

Arithmetic Sequence

Formula

an = a1 + f × (n – 1)

Where:

  • an is the nth term
  • a1 is the first term
  • f is the common difference
  • n is the term number

Example

Sequence: 1, 3, 5, 7, 9, 11, 13, …

First term (a1) = 1

Common difference (f) = 2

10th term: 1 + 2×(10-1) = 19

Calculation Results
nth Term (an): 19
Sum of Sequence: 100
1, 3, 5, 7, 9, 11, 13, 15, 17, 19

Geometric Sequence

Formula

an = a × rn-1

Where:

  • an is the nth term
  • a is the first term
  • r is the common ratio
  • n is the term number

Example

Sequence: 1, 2, 4, 8, 16, 32, 64, 128, …

First term (a) = 1

Common ratio (r) = 2

8th term: 1 × 27 = 128

Calculation Results
nth Term (an): 128
Sum of Sequence: 1023
1, 2, 4, 8, 16, 32, 64, 128, 256, 512

Fibonacci Sequence

Formula

F0 = 0, F1 = 1

Fn = Fn-1 + Fn-2

Where:

  • Fn is the nth Fibonacci number
  • F0 = 0
  • F1 = 1

Example

Sequence: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, …

10th term: 34

Calculation Results
nth Term (Fn): 34
Sum of Sequence: 88
0, 1, 1, 2, 3, 5, 8, 13, 21, 34

How to Use This Calculator

  • Switch between tabs to select the sequence type (Arithmetic, Geometric, or Fibonacci)
  • Enter the required parameters for your sequence
  • Click “Calculate” to see the nth term, sum, and full sequence
  • Adjust the sequence length to generate more or fewer terms
  • Use “Reset” to clear inputs and results for the current tab