Flight Dead Reckoning Calculator
Calculate flight time, ground speed, and fuel required from distance, true airspeed, wind, and fuel burn rate.
Essential for VFR and IFR flight planning.
Aviation dead reckoning
Dead reckoning in aviation means calculating your expected position, flight time, and fuel requirements from known or forecast data, without relying on GPS or radio navigation. It is the foundation of all flight planning, used to check navigational instruments and as a backup if electronic systems fail.
The core calculation
Ground Speed = TAS ± Wind Component Flight Time = Distance ÷ Ground Speed Fuel Required = Flight Time × Fuel Burn Rate
A headwind component (wind opposing the direction of flight) reduces ground speed. A tailwind component (wind behind the aircraft) increases ground speed. The wind component along the route depends on the angular difference between wind direction and track. Only the component along the route affects ground speed.
Wind correction angle
Cross-wind components, the ones perpendicular to track, require a correction angle to maintain the desired track. This calculator takes the along-track component as an input and stops there. To work that component out from a raw wind direction and speed, or to get the heading to fly, use the Wind Correction Angle Calculator and bring its headwind figure back here.
A worked pair: a 120-knot aircraft on a course of 090° in a 30-knot wind from 360° gets a 30-knot pure crosswind and zero headwind component. That is the case pilots most often get wrong by eye, because a strong wind that feels punishing on the controls costs nothing at all in ground speed.
Route legs
Most flights involve multiple legs (route segments) with different winds, altitudes, and distances. This calculator handles a single leg. For multi-leg flights, calculate each leg separately and sum the fuel and time totals.
Planning margins
Always add planning margins to calculated fuel:
- Navigate with a comfortable reserve above regulatory minimums
- Build in 10-15% contingency for unexpected winds or routing changes
- Never assume forecast winds are accurate: check actual winds against forecast at the first waypoint and revise fuel planning if significantly different
US day VFR requires fuel to the destination plus 30 minutes at cruise; night VFR and IFR require 45 minutes. Those are legal floors, not plans. The result below adds both figures so you can see what the leg actually costs against what the rules demand.
Dead reckoning is a skill that requires practice. Use it alongside GPS as a cross-check, and you will always know where you are.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.