299,792,458 meters/secondSI OFFICIAL LABORATORY MEASUREMENT IN A VACUUM10% of the speed of light: 29,979,245.8 m/s From Notation 1 to 202 (that is from the first moment of time to the current time), the simple calculation, c = ℓP ÷ tP, renders a variable speed of light, all well within .1% of the laboratory value. To explore those numbers, see line 10 within our horizontallyscrolled chart. 299,792,422.79 meters/secondPlanck Length divided by Planck time equals 299,792,434.14 meters/second.From the Planck units, the difference is just 35 meters/second, less than .0001% difference from the current SI standard rating in 2019. In the following notations the fastest interval is within Notation 16 where it is at 299,982,157.27 meters/second. The slowest calculation is within notation 76 which is 299,759,426.55 meters/second. The difference from the fastest to the slowest is 222,720.72 m/s. From the fastest interval there is a 189,699.27 m/s difference. From the slowest interval, there is just 33,031.45 m/s difference. 299,774, 296.4 meters/second

“In 1899 Max Planck defined Planck Time as the unit of time (in a system of natural units or “Planck units”) whereby light travels the distance of one (1) Planck length in a vacuum. The calculation, Planck Length divided by Planck time is equal to 299,792,422.79 meters/second.”