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How-to guide

How to Calculate Pendulum Period: Formula, Steps & Examples

Learn how to calculate Pendulum Period — the formula explained step by step, with worked examples and a free calculator to check your answer.

By Vikram Iyer, M.Sc Mathematics · Updated Jun 2026 · 2 min read

Calculating your period is straightforward once you know the Pendulum Period formula and what each input means. This guide explains the method in plain language, walks through a manual calculation, and gives worked examples you can follow — then you can do it instantly with the Pendulum Period Calculator.

What is Pendulum Period?

The Pendulum Period calculation tells you your period from a few simple inputs. The figure you are solving for here is the period.

The Pendulum Period formula

The core formula is:

Period = 2 × 3.141592653589793 × √(Pendulum length ÷ Gravity)

Here is what each input means:

  • Pendulum length — a value measured in m. Example: 1 m.
  • Gravity — a value measured in m/s². Example: 9.81 m/s².

How to calculate it step by step

  • Write down the pendulum length (for example, 1 m).
  • Write down the gravity (for example, 9.81 m/s²).
  • Apply the formula above to get your period.
  • Double-check the result with the Pendulum Period Calculator.

Worked examples

Example 1

Input / OutputValue
Pendulum length1 m
Gravity9.81 m/s²
Period2.0061
Frequency0.4985

With pendulum length of 1 m and gravity of 9.81 m/s², the period works out to 2.0061.

Example 2

With pendulum length of 2 m and gravity of 9.81 m/s², the period works out to 2.8370.

ResultValue
Period2.8370
Frequency0.3525

Example 3

With pendulum length of 5 m and gravity of 9.81 m/s², the period works out to 4.4857.

ResultValue
Period4.4857
Frequency0.2229

Tips for an accurate result

  • Keep your units consistent — mixing, say, months with years or grams with kilograms is the most common source of error.
  • Round only at the very end. Rounding inputs early can shift the final answer noticeably.
  • Re-run the numbers whenever an input changes, rather than estimating from an old result.

Prefer not to do the maths by hand? — the Pendulum Period Calculator does it instantly, for free, with the formula and a worked example built in.

Continue exploring science calculators with these tools: Impulse Calculator, Elastic Potential Energy Calculator, Thermal Expansion Calculator, Buoyancy Force Calculator, RPM to Linear Speed Calculator.

Calculators in this guide

Frequently asked questions

The formula is: Period = 2 × 3.141592653589793 × √(Pendulum length ÷ Gravity). With pendulum length of 1 m and gravity of 9.81 m/s², the period works out to 2.0061.

Gather each input, apply the formula step by step keeping your units consistent, and round only at the end. You can verify your answer instantly with the Pendulum Period Calculator.

It uses the standard formula with exact arithmetic, so the result is correct for the inputs you enter. Bear in mind that real-world outcomes can still differ when underlying assumptions change.

Vikram Iyer · M.Sc Mathematics

Vikram Iyer is a mathematics educator with over fifteen years of teaching experience, specialising in making quantitative concepts clear and practical for everyday use.