Dates & Time · Relativistic & Precision Physics Time
Gravitational Time Dilation (Schwarzschild Metric) & Satellite Atomic Clock Drift Calculator: inputs, method, and how to read the result
Calculate GR gravitational clock speedup (+45.7 μs/d for GPS) and SR orbital slowdown (−7.2 μs/d).
Choose inputs for the case you are checking
The defaults are illustrative. Replace them with values for your case and keep the units shown beside each field.
- Orbital Altitude Km: Satellite altitude above Earth’s surface in km (ISS LEO ≈ 400 km; GPS MEO = 20,180 km; Geostationary = 35,786 km).
What the calculation includes
With the default values shown, Net Relativistic Clock Drift per Day is 38.497 μs / day. The calculation follows Gravitational Time Dilation Formula; the formula and variable definitions above show how the inputs combine.
One-input check: With the other defaults held constant, changing Orbital Altitude Km from 20,180 km to 22,198 km changes Net Relativistic Clock Drift per Day from 38.497 μs / day to 40.026 μs / day. This is a comparison inside the calculator's stated model, not a prediction.
Where to use caution
- Uses official NIST Special Publication 811, IEEE/RFC systems engineering, APA psychometric, and USNO astronomical formulas.
- Empirical metallurgy and calendar conversions represent standard reference-condition approximations.
Scope: Global NIST, IEEE, APA & Astronomical Standard Check the assumptions and limitations against your situation before relying on the estimate.
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