Planck time: a natural interval

planckTime is the time light takes to travel one Planck length in vacuum. It is a natural unit derived from gravity, quantum mechanics, and relativity.

Use

It provides a scale for theoretical models of the very early universe. It is linked directly to planckLength and speedOfLight.

Caveats

Planck time is not established as the smallest possible duration. Use SI seconds for experimental timing and divide to make a deliberate unit conversion. It belongs with planckTemperature in Planck-unit estimates.

Use Planck Time in a calculation

Enter planckTime on a calculator line to see its built-in value, or place the name inside a longer expression. Keep any displayed unit attached when converting or combining physical quantities, and check that every other value uses a compatible dimension.

The example above is editable, so you can replace surrounding values and test the constant in your own formula. Browse all constants to compare related values and notation.