Time-Speed-Distance
Distance, time, groundspeed and estimated time en route with a moving aircraft or distance timeline.
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Single leg: choose what you want solved — time, groundspeed or distance — and set the other two; the solved slider follows the answer and is greyed out. Multi-leg plan: enter up to six legs with their own distance and groundspeed and read the time of each leg, the cumulative time and the ETA at every waypoint from the departure clock you type.
The upper track is distance, the lower track is time; the faint lines joining the two show how a slow leg stretches on the time track while staying short on the distance track. Drag the amber aircraft along the distance track (or press Play) to read distance flown and remaining, time elapsed and remaining, the clock time now and the next waypoint with its ETA.
Switch units freely: NM / SM / km for distance and kt / mph / km/h for speed; the stored problem is converted with the exact factors, so the answer does not change. The rules-of-thumb row gives the mental-math forms used in training (NM per minute = groundspeed ÷ 60, the six-minute rule) beside the exact arithmetic.
Assumption: constant groundspeed on each leg and no climb, descent or wind change within a leg (groundspeed already includes the wind — take it from the Wind Triangle Solver). The rules of thumb are training conventions, not FAA formulas. Fuel is not part of this tool; the Fuel Planning tool reuses these legs.
Exact arithmetic (PHAK ch. 16 Navigation, the time-speed-distance relations of the flight computer): time = distance ÷ groundspeed, distance = groundspeed × time, groundspeed = distance ÷ time. Multi-leg: leg time = leg distance ÷ leg groundspeed; cumulative time and distance by summation; ETA = departure clock + cumulative time (24-hour wrap, days carried); average groundspeed = total distance ÷ total time. Aircraft position at an elapsed time: the leg containing that time, distance flown = cumulative distance at its start + leg groundspeed × time in the leg. Unit factors (NIST SP 811): 1 NM = 1,852 m, 1 SM = 1,609.344 m.
Verified: the E6-B instruction manual's time-speed-distance problems (p. 8 245 NM at 150 kt = 1:38; p. 10 26 NM in 13 min = 120 kt; the five sample problems, answers p. 37) reproduced exactly; NIST conversion factors checked; legs with zero groundspeed give a visible impossible state instead of an infinite time.
Rules of thumb shown (training conventions): distance per minute = groundspeed ÷ 60 (60 kt = 1 NM/min, 120 kt = 2 NM/min); the six-minute rule: distance covered in six minutes = groundspeed ÷ 10; minutes = 60 × distance ÷ groundspeed. They are exact rearrangements, convenient for mental use; the readout always shows the computed value.
- FAA Pilot’s Handbook of Aeronautical Knowledge, FAA-H-8083-25C (2023), ch. 16 Navigation — time, speed and distance relations; groundspeed; estimated time en route and of arrival; flight computer use
- NIST Special Publication 811 (2008), Appendix B.8/B.9 — conversion factors (nautical mile 1,852 m; mile 1,609.344 m)
- E6-B flight computer instruction manual, pp. 5–10 — time-speed-distance problems and sample answers (p. 37), used as published test values