# Ballistic Coefficient Calculator

URL: https://speedycalculator.com/calculators/physics/ballistic-coefficient/
Last updated: 2026-10-30

> The ballistic coefficient calculator finds how well a projectile overcomes air resistance from its mass, cross-sectional area and drag coefficient.

## Inputs

- Mass of projectile (g, kg, mg, lb, oz, gr)
- Cross-sectional area (cm², mm², m², in²)
- Drag coefficient C_d

## Results

- Ballistic coefficient

## Formula

```
BC = m / (C_d × A)
```

## Explanation

The ballistic coefficient (BC) measures how well a projectile keeps its speed in flight. A high BC – heavy, narrow and streamlined – means less drag deceleration, a flatter trajectory and less wind drift. It is used for bullets, artillery, skydivers and re-entering spacecraft.

### How to use the Ballistic Coefficient Calculator

- **Mass of projectile**
- **Cross-sectional area**
- **Drag coefficient C_d**

Results update as you type, every field has its own unit menu, and everything is calculated in your browser.

### How it works

The mass is divided by the product of the drag coefficient and the frontal area. A larger value means the projectile is less affected by drag. The result is shown in kg/m² and in the lb/in² form used by ammunition makers (without their reference-projectile form factor).

### Inputs explained

FieldWhat to enterMass of projectileUnits: g, kg, mg, lb, oz, grCross-sectional areaUnits: cm², mm², m², in²Drag coefficient C_dA number

### Example values

How the main result changes when **Mass of projectile** changes and everything else stays at the example values above:

Mass of projectile (g)Ballistic coefficient (kg/m²)0.0050.33330.00750.50.010.66670.01250.83330.01510.021.3333

## Worked example

Inputs — Mass of projectile: 0.01 g; Cross-sectional area: 0.5 cm²; Drag coefficient C_d: 0.3.

Results — **Ballistic coefficient = 0.6667 kg/m²**.

## Key terms

- **Drag coefficient**: A dimensionless number describing how streamlined a shape is.

## FAQ

**What is a good ballistic coefficient for a bullet?**
Rifle bullets typically range from about 0.2 to 0.7 (lb/in², G1 model).

**Why does a heavier bullet have a higher BC?**
More mass per unit of frontal area resists drag deceleration better.

**Is BC constant during flight?**
No – it changes with speed, especially near the speed of sound.

**What is the G1 standard?**
A reference projectile shape used to express bullet BCs relative to a standard drag curve.


## Sources

- [HyperPhysics (Georgia State University)](http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html)
- [The Engineering ToolBox](https://www.engineeringtoolbox.com/)