Time & Date · Travel & Distance
Flight Duration Estimator
Estimate flight time between two cities or airports from the great-circle distance, a typical cruising speed and an allowance for taxiing, climb and descent.
A ready-made version of the Great-circle Distance Calculator.
Your inputs
Quick start — try a typical case
Typical jets cruise at 800–900 km/h.
Your result Live
Approximate Flight Time, New Delhi → London
8 h 24 min 38 s
6,724.04 km at 850 km/h plus 30 min for taxi, climb and descent
- Great-circle Distance
- 6,724.04 km (4,178.13 mi)
- Initial Bearing
- 315.6° (NW)
- Final Bearing
- 260.2° (W)
- Midpoint
- 46.8606° N, 46.2998° E
- On a Perfect Sphere (haversine)
- 6,711.26 km — -0.19 % different
Real flights follow air routes and winds, so actual times vary — often by 30 minutes or more on long routes.
How this is calculated
Vincenty's inverse formula on the WGS-84 ellipsoid; sphere check: d = 2R·asin√(sin²(Δφ/2) + cos φ₁ cos φ₂ sin²(Δλ/2))
- φ, λ
- Latitude and longitude
- R
- Mean Earth radius, 6,371.0088 km (for the haversine comparison)
The shortest path between two places on a globe is a 'great circle' — the reason flights from India to North America pass over the Arctic. Because the Earth is slightly flattened, the distance is computed on the WGS-84 ellipsoid used by GPS (accurate to millimetres); the simpler spherical formula is shown for comparison and differs by up to about 0.5 %.
Assumptions & sources
- City distances use approximate city-centre coordinates — use exact coordinates for airports or addresses.
- Distance is over the Earth's surface, ignoring altitude and terrain; road distances are longer.
- 1Direct and Inverse Solutions of Geodesics on the Ellipsoid (Vincenty, 1975) — Survey Review
- 2World Geodetic System 1984 (WGS 84) — U.S. National Geospatial-Intelligence Agency
Calculator ID GEO-GC-001/flight · version 1.0.0
Common questions
Why do flights in the same direction take different times?
Winds: the jet stream can add or remove 30–60 minutes on long east–west flights. Routes also detour around restricted airspace.
What speed should I use?
Around 850 km/h for most jets; 500–550 km/h for turboprops on short regional routes.