Number Sequence Calculator – Find Number Patterns
Generate arithmetic, geometric and Fibonacci sequences and sums.
About the Number Sequence Calculator
What is the Number Sequence Calculator?
A number sequence calculator generates arithmetic, geometric or Fibonacci sequences and their sums.
Why use this calculator?
Sequences model steady growth, constant additions and everything in between — from saving plans to population growth to spiral shells.
How to use it
- Pick the sequence type.
- Enter the first term and the common difference or ratio.
- Choose how many terms and read the list plus the sum.
Formula
Arithmetic: aₙ = a₁ + (n−1)d; Geometric: aₙ = a₁·r^(n−1).
For Fibonacci the "d" field becomes the second seed term.
Frequently Asked Questions
What is the Fibonacci sequence?
Each term is the sum of the previous two, starting (usually) 0, 1, 1, 2, 3, 5, 8...
When are sequences useful?
Arithmetic models constant savings; geometric models compound interest; Fibonacci appears in nature and algorithms.
What order of operations does this use?
It follows standard PEMDAS/BODMAS rules: parentheses, exponents, multiplication and division, then addition and subtraction.
How precise are the answers?
The calculator uses double-precision floating-point math (about 15 significant digits) and rounds the display. For exact symbolic results use dedicated algebra software.
Can I enter negative numbers or decimals?
Yes. Negative values, decimals and very large or small numbers are all supported unless a field says otherwise.
What does it mean if I get an error?
Errors usually mean an invalid input, such as division by zero or a negative value where only positives make sense. Check your entries and try again.
Is this calculator free to use?
Yes. Every calculator on this site is completely free, with no hidden fees, no subscriptions and no limits on how many times you can use it.
How accurate are the results?
We use standard, widely accepted formulas and calculate in your browser using double-precision arithmetic. Results are rounded for readability, so treat them as reliable estimates rather than a guarantee. Real-world factors can vary the true figure.
Can I add this calculator to my own website?
Yes. Open this calculator page and use the "Add to your website" box in the sidebar to copy a ready-made iframe snippet, then paste it into any HTML page.
Does it work on a phone or tablet?
Yes. The layout is fully responsive, so it works on desktops, laptops, tablets and mobile phones, and every input adapts to touch screens.