Physics

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Ballistic Coefficient Calculator.

Calculate mass ballistic coefficient from mass, drag coefficient, and diameter.

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01

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Results update as you type.

referenceArea: 0.000064

referenceArea

0.000000
ballisticCoefficient: 523.966891

ballisticCoefficient

0.000000

Use Cases

Compare projectile efficiency

Use the calculator to compare the ballistic coefficients of different projectiles to see which one retains velocity better in flight.

Example: Compare a 0.01 kg bullet with a drag coefficient of 0.2 and diameter 0.01 m to another with different parameters.

Design and testing

Engineers and hobbyists can quickly estimate the ballistic coefficient of a new projectile design before conducting field tests.

Example: Estimate the BC for a custom dart with mass 0.005 kg, drag coefficient 0.3, and diameter 0.005 m.

Frequently Asked Questions

What is the mass ballistic coefficient?
The mass ballistic coefficient (BC) is a measure of a projectile's ability to overcome air resistance during flight. It is calculated by dividing the projectile's mass by the product of its drag coefficient and the square of its reference diameter. A higher BC indicates better aerodynamic efficiency.
How do I use this calculator?
Enter the projectile's mass in kilograms, its drag coefficient (a dimensionless number), and its reference diameter in meters. The calculator will then compute the mass ballistic coefficient using the formula BC = mass / (drag coefficient * diameter^2).
What units are used for the ballistic coefficient?
The calculator outputs the mass ballistic coefficient in units of kg/m². This is derived from the input units: mass in kg, drag coefficient dimensionless, and diameter in meters.

Tips & Common Mistakes

Tips

  • Ensure the drag coefficient is appropriate for the projectile's shape and speed regime; it varies with velocity.
  • Use consistent units: mass in kilograms and diameter in meters to get the BC in kg/m².
  • For accurate comparisons, use the same reference diameter for all projectiles.
  • Remember that a higher ballistic coefficient generally means less velocity loss due to air resistance.

Common Mistakes to Avoid

  • Using diameter in millimeters or centimeters without converting to meters, which leads to incorrect BC values.
  • Confusing drag coefficient with ballistic coefficient; they are different parameters.
  • Assuming the drag coefficient is constant; it changes with speed and air density.

Last updated: August 13, 2026