Calculate thrust required to overcome drag from drag coefficient, speed and area, with sea-level air density filled in, or solve for any of those values.

Pick a typical shape from the list or enter your own. It must match the reference area you enter.

1.225 kg/mยณ is standard sea-level air at 15 ยฐC. Change it for altitude or temperature.

Use frontal area only when the drag coefficient uses frontal area.

Optional settings

Related Calculators

Thrust Required Formula

The calculator uses the drag equation. For steady level motion with aligned thrust and no other unbalanced along-path forces, thrust required is equal to aerodynamic drag.

T = 0.5ร—Cdร—rhoร—V2ร—A

Rearranged forms:

Cd = (2ร—T)/(rhoร—V2ร—A)
rho = (2ร—T)/(Cdร—V2ร—A)
V = โˆš((2ร—T)/(Cdร—rhoร—A))
A = (2ร—T)/(Cdร—rhoร—V2)
  • T = thrust required, in newtons or pounds-force
  • Cd = drag coefficient, unitless
  • rho = air density
  • V = speed relative to air
  • A = reference area used to define Cd (frontal area only when that convention applies)

This drag-only calculation does not include rolling resistance, climb force, acceleration or propulsion losses. Wind must be accounted for in speed relative to air; ground speed alone is insufficient.

Useful Tables

The numerical ranges below are illustrative assumptions, not verified typical ranges or recommended defaults. Air density depends on pressure and temperature; use measured or appropriate atmospheric data. Use a drag coefficient measured for the same reference area, orientation and flow regime.

Condition Illustrative density assumption Notes
Sea level, standard atmosphere 1.225 kg/mยณ Standard sea-level reference; actual conditions vary
Warm low-altitude day 1.15 to 1.20 kg/mยณ Lower density reduces drag
High altitude Below 1.0 kg/mยณ Depends strongly on altitude and temperature
Object type Illustrative Cd assumption Comment
Streamlined car 0.20 to 0.35 Varies with shape and underbody design
SUV or truck 0.35 to 0.60 Larger frontal area also increases thrust required
Cyclist upright 0.7 to 1.1 Position changes the result a lot
Flat plate facing flow 1.1 to 1.3 High-drag reference shape

Result Notes

With density, area and drag coefficient held constant, doubling airspeed makes aerodynamic drag four times larger. The coefficient itself can change with flow conditions.

Use consistent, real-world inputs. A small error in frontal area or drag coefficient can noticeably change the final thrust value.