Ballistic Coefficient Calculator
Enter a ballistic coefficient with its drag model and see exactly what it buys you: drop, wind drift, retained velocity and energy downrange. Add a second load to compare two coefficients side by side.
Loads
Up to 4 loads share one chart and one table. Each keeps its own inputs.
Load inputs
Atmosphere
A station reading is used as entered. A sea-level reading is reduced to your altitude first, so do not subtract for altitude twice. Atmosphere guide.
Output
Solution at range
Drop vs range (in over yd)
| Range (yd) | Drop (in) | Drop MOA | Drop MIL | Wind (in) | Wind MOA | Wind MIL | Vel (fps) | Energy (ft·lbf) | Time (s) |
|---|---|---|---|---|---|---|---|---|---|
| 0 | -1.80 | 0.00 | 0.00 | 0.00 | 0.00 | 0.00 | 2790 | 2489 | 0.000 |
| 100 | -0.00 | -0.00 | -0.00 | 0.52 | 0.50 | 0.15 | 2651 | 2248 | 0.111 |
| 200 | -3.15 | -1.50 | -0.44 | 2.01 | 0.96 | 0.28 | 2517 | 2025 | 0.227 |
| 300 | -11.80 | -3.76 | -1.09 | 4.65 | 1.48 | 0.43 | 2386 | 1820 | 0.349 |
| 400 | -26.59 | -6.35 | -1.85 | 8.52 | 2.03 | 0.59 | 2259 | 1631 | 0.479 |
| 500 | -48.17 | -9.20 | -2.68 | 13.62 | 2.60 | 0.76 | 2136 | 1459 | 0.615 |
| 600 | -77.37 | -12.32 | -3.58 | 20.12 | 3.20 | 0.93 | 2018 | 1301 | 0.759 |
| 700 | -115.09 | -15.70 | -4.57 | 28.13 | 3.84 | 1.12 | 1903 | 1157 | 0.912 |
| 800 | -162.44 | -19.39 | -5.64 | 37.80 | 4.51 | 1.31 | 1791 | 1025 | 1.075 |
| 900 | -220.70 | -23.42 | -6.81 | 49.33 | 5.23 | 1.52 | 1682 | 904 | 1.248 |
| 1000 | -291.11 | -27.80 | -8.09 | 62.78 | 6.00 | 1.74 | 1576 | 794 | 1.432 |
Dimmed rows are below the speed of sound, where the point-mass model and published coefficients both get less trustworthy. Positive drop means the bullet is above your line of sight. Values are shown in imperial units — switch in the header.
Using a coefficient correctly
A ballistic coefficient is not a property of the bullet alone — it is a comparison against a reference shape. The G1 reference is a blunt flat-based form; G7 is a long boat-tail closer to a modern match bullet. Feed a G7 number into a G1 field and the calculator will flatter your trajectory badly, because the two scales are not interchangeable. Always select the model the maker published the number against.
This solver carries the full standard drag tables for G1, G2, G5, G6, G7 and G8 and integrates the curve you select directly, with no conversion step in between. That matters most past 600 yards and through the transonic band, where the shape of the drag curve — not just its overall level — decides how quickly the bullet sheds speed.
The fastest way to feel what a coefficient is worth is to compare. Load your bullet, add a second load with a different BC and the same muzzle velocity, and watch the wind column rather than the drop column: drop can be dialled, wind has to be read. The drag models guide explains the shapes behind the numbers, and the preset library gives you documented factory coefficients to test against.
When you are ready to work with the full solution, the ballistic calculator home page carries the same workspace and the kinetic energy calculator shows what the retained velocity is worth on target.
Frequently asked questions
- What is a ballistic coefficient?
- It is a ratio comparing your bullet's ability to hold velocity against a standard reference projectile. A BC of 0.5 means the bullet sheds velocity at roughly half the rate of the reference shape. Because the reference shapes differ, a coefficient is only meaningful alongside the drag model it was measured against.
- How do I convert a G7 BC to a G1 BC?
- You do not need to here — select the G7 model and enter the G7 number, and the solver integrates the G7 drag curve directly. Rough conversions between the models exist, but they are only valid across a narrow velocity band and they throw away most of the reason G7 was published in the first place.
- Can I work out a bullet's BC from my own drop data?
- Not automatically on this page, but you can do it by hand quickly: enter your load with the maker's coefficient, compare the predicted drop against a measured come-up at distance, and adjust the coefficient until the two agree. Truing the BC this way absorbs small errors in muzzle velocity as well, so confirm your chronograph reading first.
- Does a higher BC always shoot flatter?
- Not on its own. Muzzle velocity dominates the first few hundred yards, so a fast light bullet can shoot flatter up close and still lose badly to a heavy high-BC bullet at 800 yards on both drop and wind. Wind drift is where a high coefficient repays you most.