Pendulum Period Calculator
Calculate the period and frequency of a simple pendulum.
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A simple pendulum's period depends only on its length and gravitational acceleration - mass does not matter. This was discovered by Galileo and used for centuries in clock design. A 1-meter pendulum has a period of almost exactly 2 seconds, which is why grandfather clocks use meter-long pendulums.
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Frequently asked questions
T = 2π√(1/9.80665) = 2.006 seconds. This is why grandfather clocks use pendulums close to 1 meter - they tick once per second (half period).
Period is proportional to the square root of length. Doubling the length increases the period by √2 (about 1.414x). A 4-meter pendulum has twice the period of a 1-meter one.
No, mass has no effect on the period of an ideal simple pendulum. A 1 kg bob and a 100 kg bob on the same length string swing at the same rate.
On the Moon (g = 1.625 m/s²), a 1-meter pendulum has a period of 4.93 seconds - about 2.45 times slower than on Earth. Lower gravity means slower swinging.
Solve L = gT²/(4π²) = 9.80665 × 1 / 39.478 = 0.2485 meters or about 24.85 cm. This is the length used in many metronome designs.