Number Sequence Calculator

Detect arithmetic, geometric, Fibonacci, or polynomial sequences and predict next terms.

Calculator Numbers & Math Updated Apr 20, 2026
How to Use
  1. Enter at least 3 numbers separated by commas or spaces.
  2. Classifier identifies the pattern and extrapolates the next 5 terms.
Input
Presets
Analysis

Show Work

Enter values to see the step-by-step calculation.

Patterns detected

Arithmetic
a_n = a₁ + (n−1)d
Geometric
a_n = a₁ · r^(n−1)
Fibonacci-like
a_n = a_(n−1) + a_(n−2)

About the Number Sequence Calculator

The Number Sequence Calculator gives you a fast, free answer for everyday maths and number work without sending anything off your device. Detect arithmetic, geometric, Fibonacci, or polynomial sequences and predict next terms.

How it works

Enter your figures and the result appears instantly, updating the moment you change anything. There is no submit button and nothing to wait for, so it is easy to try a few what-if numbers and compare the results. Just check each box holds the kind of value it expects.

Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.

Frequently Asked Questions

How do I use the Number Sequence Calculator?

Simply type your numbers and read the result, which refreshes the instant you change something. There is nothing to submit and nothing to wait for.

Does it cost anything or need an account?

No. The tool is completely free, there is no account to create, and it keeps working offline after the page first loads.

Is anything I type uploaded?

No. The tool works entirely on your device, so the values you enter never leave your browser.

Common Use Cases

Check your work

Worked it out yourself? Use the Number Sequence Calculator to make sure your answer is right.

Learn while you do it

Seeing what you put in and what comes out helps you understand how they fit together.

Get an answer fast

Type what you have and get the answer in seconds — on a phone, tablet, or computer.

Stays on your device

Your inputs never leave the browser — nothing is uploaded, logged, or stored anywhere.

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