Drag Equation Calculator

Your details

Pick the unknown you want to find. All other fields become inputs.
Density of the surrounding fluid. Air at sea level is 1.225 kg/m^3; fresh water is 998 kg/m^3.
kg/m^3
Density of the surrounding fluid.
kg/m^3
Speed of the object relative to the fluid. 30 m/s is about 108 km/h or 67 mph.
m/s
Pick a shape to auto-fill the drag coefficient below.
Dimensionless number that captures how streamlined the object is. Lower is more aerodynamic.
Frontal (projected) cross-sectional area of the object perpendicular to the flow direction.
m^2
The aerodynamic drag (resistance) force acting on the object.
N
Drag force (Fd)Turbulent flow
129.544

Net aerodynamic resistance force on the object

Velocity (v)30
Drag coefficient (Cd)0.47
Reference area (A)0.5
Fluid density (rho)1.225
Dynamic pressure (q)551.25
Reynolds number (approx.)1,435,700
Flow regimeTurbulent
_unitLabelmetric
0.47 Cd
Very streamlined<0.1Streamlined0.1-0.5Bluff body0.5-1Highly bluff1+

Drag force: 129.54 N

  • The drag force is 129.54 N.
  • A Cd of 0.470 is moderately streamlined (like a sphere or sedan).
  • Dynamic pressure is 551.25 Pa, representing the kinetic energy of the flow per unit area.
  • The estimated Reynolds number is 1,435,700: turbulent conditions.

Next stepDrag force scales with the square of velocity, so doubling your speed quadruples the drag. Reducing Cd or frontal area is far more effective at higher speeds.

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