Escape Time Calculator: Black Holes and Gravitat...

Gravitational Time Dilation and Escape Time

Near massive objects, time runs slower — a prediction of Einstein's general relativity confirmed by GPS satellite corrections, gravitational wave detections, and pulsar timing. The escape time calculator explores how long it takes signals or particles to escape a gravitational well, accounting for time dilation.

🕳️ Escape Time Calculator

Free calculator for instant results.

Calculate Now →

📐 Formula

t_far = t_near / √(1 − rs/r)

rs = Schwarzschild radius = 2GM/c², r = radial coordinate. Time dilation factor → ∞ as r → rs (event horizon). For flat space: t = distance/c.

📝 Worked Example

At r = 1.5rs (1.5x Schwarzschild radius):
t_far = t_near / √(1 − 1/1.5) = t_near / √(1/3) = t_near × √3 ≈ 1.73 × t_near
Time appears to run 1.73x slower as seen from far away.

📝 How to Use

Enter MassBlack hole or massive object mass in solar masses or kg.

Enter Radial DistanceDistance from center in meters or Schwarzschild radii.

Calculate Time DilationView gravitational time dilation factor at that distance.

Find Escape ConditionsSee whether the position is inside or outside the event horizon.

❓ FAQ

Can anything escape a black hole?

Nothing — not even light — can escape from inside the event horizon (r < rs). Hawking radiation is a quantum effect from the horizon surface, not from inside.

What is gravitational redshift?

Light climbing out of a gravity well loses energy, stretching its wavelength toward red. At the event horizon, infinite redshift occurs — light cannot escape.

Gravitational Time Dilation and Escape Time