Free Maths Calculator
Geometric Sequences Calculator
A geometric sequence multiplies by the same number each time instead of adding. Give the first term and the ratio, or let the calculator find the ratio from two terms, and it builds the nth term rule and works out any term you ask for. Doubling, halving and interest growth all live here.
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Method, Step by Step
Worked Example
A sequence starts 3, 6, 12, 24. Find the 7th term.
- Each term doubles, so the common ratio is 6 ÷ 3 = 2
- The nth term rule is 3 × 2ⁿ⁻¹
- For term 7:3 × 2⁶ = 3 × 64 = 192
Answer: 192
Try These Yourself
Find the common ratio of 5, 15, 45.Show answer
Answer: 3
15 ÷ 5 = 3.
What is the 5th term of 2, 6, 18, ...?Show answer
Answer: 162
2 × 3⁴ = 2 × 81.
Find the next term of 80, 40, 20.Show answer
Answer: 10
The ratio is 0.5, so halve again.