Pendulum period calculator
Find how long a pendulum takes to swing for its length, or the length that gives a period or a tempo.
That's 1.01× as long as a seconds pendulum, while a playground swing is 2.5× longer. It takes 2.006 s to swing there and back, ticking 59.81 times a minute.
What it means
How long is that pendulum?
Simple pendulum, small swings, g = 9.80665 m/s². Length is from the pivot to the centre of the bob.
Every unit
That pendulum in every unit
Learn
Three things worth knowing
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A meter, two seconds
A 1 m pendulum has a period of 2.0 s; 25 cm gives 1 s; 4 m gives 4 s.
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Galileo’s chandelier
Galileo is said to have timed a swinging lamp in Pisa cathedral against his pulse in 1583; Huygens built the first pendulum clock in 1656.
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Period or swing
A period is there and back; one swing is half of it. A seconds pendulum has a 2-second period.
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Popular pendulum conversions
Background
About pendulums
For small swings, a pendulum’s period depends only on its length: T = 2π √(L ÷ g). Quadruple the length and the swing takes twice as long. A 0.994 m pendulum swings once a second, the “seconds pendulum” of grandfather clocks.