Free · Kinematics calculators — How things move ⏱️

Drag-Based Ballistic Mass to Area

Find the drag-based mass-to-area coefficient, or solve for mass, reference area or drag coefficient using consistent SI or customary units.

  • Formula & worked example
  • Private in your browser
  • No signup
Go to tool

Calculator inputs

Loading calculator…

How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

A 12 kg body with drag coefficient 0.3 and reference area 0.02 m² has m/(Cd A) = 2,000 kg/m². Higher values mean less drag acceleration at the same dynamic pressure.

B = m/(Cd A). With drag D = (ρv²/2)Cd A, drag acceleration is D/m = (ρv²/2)/B.

Worked example

Enter these known values and leave the other values blank.

Body mass
12000 g
Drag coefficient for this area
0.3
Drag reference area
20000 mm²
Drag-based mass-to-area coefficient
2000 kg/m²

Assumptions and limitations

  • This coefficient is m/(Cd A), using the same reference area that defines Cd. It is a mass-per-area quantity, not pressure.
  • Cd depends on shape, attitude and flow conditions. This calculation uses the supplied value at one condition; it does not determine Cd or predict a trajectory.
  • For aerodynamic data based on a different reference area, transform Cd consistently before entering it. Mixing conventions changes the result.
  • Mass, area, Cd and B are positive. A zero drag coefficient corresponds to no modeled drag and does not have a finite B in this relation.
  • The lb mass/in² option uses pound mass and square international inches. It is not psi or pound-force per area.
  • Published G1/G7 projectile ratings use reference drag conventions and cannot be entered as this m/(Cd A) quantity without a justified conversion.

Common questions

What does a larger coefficient mean?

At equal dynamic pressure, drag acceleration equals dynamic pressure divided by this coefficient, so a larger B gives smaller drag acceleration.

Can I use a G1 or G7 rating directly?

No. Those ratings depend on a standard reference drag convention. This page uses actual mass, Cd and the area used to define that Cd.

Is lb mass/in² a pressure unit here?

No. The numerator is mass, not force. Keep it distinct from psi.

Can I solve for a missing area or drag coefficient?

Yes. Enter the other three positive quantities and leave the unknown blank. All four captured quantities are editable.

References

The drag-based coefficient uses mass divided by drag coefficient and reference area. Positive denominators are required for each inverse. Mass, reference area and both coefficients must be strictly positive. Pound mass per square inch uses exact international pound and inch definitions, rather than a rounded conversion factor.

Explore kinematics calculators — how things move ⏱️ or browse all physics calculators.