🧮 Number Sequence Calculator
Number sequences usually hide a simple rule: add the same amount each time (arithmetic) or multiply by the same amount (geometric). This calculator checks both patterns against the terms you enter and extends the sequence with the next three values.
Enter at least three terms separated by commas. If the numbers follow neither pattern, the calculator tells you so instead of guessing.
How to use this calculator
Type the first few terms of your sequence, separated by commas, and press Calculate. The calculator tests for an arithmetic pattern and a geometric pattern, then extends the sequence with the next three terms.
- Type at least three terms into the First terms field, separated by commas, for example 2, 4, 6, 8.
- Press Calculate and read the detected pattern: arithmetic with its common difference, or geometric with its common ratio.
- Copy the three predicted next terms to continue the sequence in your puzzle, test or homework.
- If no pattern is detected, recheck your terms for a typo, since a single wrong number breaks the pattern.
Frequently asked questions
What does this number sequence calculator detect?
It tests whether your terms form an arithmetic sequence, where each term adds a constant difference, or a geometric sequence, where each term multiplies by a constant ratio. When it finds a match, it reports the pattern type, the difference or ratio, and the next three terms.
How many terms should I enter?
Enter at least three terms, though four or five give more reliable detection. The calculator must confirm that the difference or ratio stays constant across the whole list before it trusts the pattern.
Can you show a worked example?
Enter 3, 6, 12, 24. Each term doubles the previous one, so the calculator reports a geometric sequence with common ratio 2, and predicts 48, 96 and 192 as the next three terms.
What if my sequence follows neither pattern?
The calculator tells you that no arithmetic or geometric pattern was detected. Many puzzles use other rules, such as squares, cubes or Fibonacci-style sums, which this tool does not try to guess.