Bullet Drop & Ballistics Calculator
Enter your ballistic coefficient, muzzle velocity, and zero range to get a range card showing bullet drop, wind drift, and MOA scope correction out to 500 yards. Common calibre presets included. Nothing uploaded.
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Estimates only. Always confirm with your actual DOPE (Data on Previous Engagements) at the range. Environmental conditions affect trajectory.
Range Card
| Range | Drop | Wind drift | Scope adj. | Velocity | TOF |
|---|
⚠ = transonic zone (unstable flight). ↓ = subsonic. Positive drop = bullet above line-of-sight; negative = below.
Learn more: how this range card is calculated
How the trajectory is stepped out
The calculator launches the bullet horizontally at your muzzle velocity and advances it in one millisecond steps. At every step it applies gravity at 9.81 m/s² plus a drag deceleration that scales with the square of the bullet's current velocity and divides by your ballistic coefficient.
That division is why BC matters so much. Doubling the BC halves the drag deceleration at any given speed, so the bullet holds velocity longer and reaches a distant target in less time, which leaves gravity less time to work on it.
The trajectory is recorded every 10 metres, and the card prints the rows that land on a 100 metre mark, each labelled with its yard equivalent. That is why you see ranges like 110 and 219 yards instead of round hundreds. A round yard figure only shows up when one happens to line up with a metric mark.
Reading the drop and scope columns
Drop is measured from the bullet's height at your zero range. The row nearest the zero therefore reads close to nothing, and every row past it reads negative, meaning below the line of sight.
Rows short of the zero are a special case. The reference height has not been recorded yet when those rows are written, so they print 0 cm and 0 MOA rather than the positive above-the-line figures you would expect. With a 300 yard zero that covers the first two rows on the card, so read them as missing rather than as a flat trajectory.
The scope column converts that drop into true angular minutes: drop divided by range, in radians, multiplied by 3438. You can check any row with a calculator. The 308 Winchester 168 grain preset zeroed at 100 yards shows 125.3 cm of drop at 400 m, and 1.253 divided by 400 is 0.00313 radians, or 10.77 MOA, which matches the 10.76 on the card to within rounding.
Because that figure is a real angle rather than an inch-per-hundred-yards approximation, the same MOA number holds whether you think in metres or yards.
What the model leaves out
The drag curve here is a piecewise approximation of G1, not a lookup table. It holds a flat factor below Mach 0.8, peaks at Mach 1.0 about half again as high, then settles back down above Mach 2. The transonic flag exists because that peak is where the approximation is least trustworthy.
Spin drift, Coriolis deflection, and aerodynamic jump are not modelled at all, and there is no input for temperature or humidity. Air density falls off exponentially with altitude in the underlying code, but the form has no altitude field, so every card you generate here is a sea level card.
The wind column is the crosswind speed multiplied by time of flight and then halved, which is not the same thing as a solved lag time. Real drift is closer to crosswind speed multiplied by the gap between the actual time of flight and the time the bullet would need in a vacuum.
For the 308 preset at 200 m that gap is about 8 thousandths of a second, which puts a 10 mph full value wind at roughly 4 cm of drift against the 57 cm the card prints. Read the wind column for the shape of how drift grows with distance, and take your actual holds from live fire.
FAQ
What is ballistic coefficient (BC)?
Ballistic coefficient describes how well a bullet holds velocity against air resistance. This calculator divides the drag deceleration by the BC you enter, so a higher number means the bullet sheds speed more slowly. The built-in presets run from 0.243 for a .223 Remington 55 grain up to 0.631 for a 7mm Remington Magnum 162 grain.
What is MOA in rifle shooting?
MOA, or minute of angle, is one sixtieth of a degree, which works out to about 1.047 inches at 100 yards. The scope column reports drop as a true angle, so the same figure applies at any distance. Most rifle scopes adjust in quarter MOA clicks.
What does the transonic flag on the velocity column mean?
It marks rows where the bullet is travelling between Mach 0.9 and Mach 1.3. The model uses 343 m/s for the speed of sound at sea level, so that band runs from roughly 1010 to 1460 fps. Bullets can behave unpredictably as they slow through it, and the drag approximation is at its weakest there too.