Ballistic calculator
Quick answer: enter your ballistic coefficient, muzzle velocity, zero range and scope height, and this solver returns bullet drop and wind drift in inches, MOA and MIL at every range you ask for. It integrates the same point-mass equations every serious tool uses, with the standard G1 and G7 drag curves and real air density from your temperature and altitude. If the numbers do not match what your rifle actually does, use the truing box underneath: tell it what you really saw at a known distance and it works backwards to the muzzle velocity that would have produced it, so the rest of the table is fitted to your rifle instead of to a number on a box.
Your load
Conditions
Turn on JavaScript for the live table. The worked table below is computed by the same solver when the page is built, so it shows the same maths for a common load.
Does it match your rifle? True it
This is the part every other free calculator leaves out. Shoot a distance far enough for drop to be real, record what you actually needed, and enter it here. The solver runs backwards to find the muzzle velocity that would have produced that result, and then re-runs the whole table on it.
Truing moves velocity because that is the input most likely to be wrong and the one that explains a proportional error at every distance. If the correction it suggests is enormous, the problem is probably not velocity: check your sight height, check that your coefficient is on the same scale as the drag model you picked, and check that your scope really moves what its dial says.
What this tool is, and what it is not
It is a prediction, not a measurement. A solver can be computed correctly and still be wrong about your rifle, because it only knows the numbers you typed. Nothing here replaces a confirmed dope card built by shooting at known distances.
Not modelled: spin drift, Coriolis, aerodynamic jump, and the way powder temperature shifts muzzle velocity. Those need twist rate, latitude and firing azimuth to do properly, and feeding them guesses would make the output look more precise without making it more correct.
On game, this matters more than it does on paper. A solution you have not confirmed can wound an animal you meant to kill cleanly. If you have not verified your drop at the distance you intend to shoot, that distance is not yet yours.
How the maths is checked: the solver is tested on every build against a closed-form vacuum trajectory, against three cases from an independent calculator, and against frozen output including the transonic region. The drag curves are the standard G1 and G7 tables from the late Robert L. McCoy of the US Army Ballistic Research Laboratory, published by JBM Ballistics, and they are written into our code by script rather than typed by hand. See our methodology for how we work generally.
Worked table: .30 calibre 168 gr, G1 .485, 2700 fps
Zeroed at 100 yards with a 1.5 inch sight height, 10 mph full value crosswind, standard atmosphere. These rows are produced by the same solver the calculator above runs, at the moment this page is built, so the table and the tool can never disagree.
| Range | Drop | Come-up | Wind | Wind | Velocity | Energy |
|---|---|---|---|---|---|---|
| in | MIL | in | MIL | fps | ft-lb | |
| 100 yd | -0.0 | 0.00 | 0.7 | 0.20 | 2514 | 2357 |
| 200 yd | -4.0 | 0.56 | 3.0 | 0.41 | 2335 | 2033 |
| 300 yd | -14.4 | 1.33 | 6.9 | 0.64 | 2163 | 1745 |
| 400 yd | -32.3 | 2.24 | 12.7 | 0.88 | 1999 | 1490 |
| 500 yd | -58.8 | 3.27 | 20.7 | 1.15 | 1843 | 1266 |
| 600 yd | -95.6 | 4.43 | 31.0 | 1.44 | 1695 | 1071 |
| 700 yd | -144.6 | 5.74 | 44.0 | 1.75 | 1556 | 903 |
| 800 yd | -207.9 | 7.22 | 59.8 | 2.08 | 1429 | 762 |
Why calculators disagree with real drop
The pattern in every one of these arguments is the same: several tools agree with each other and none of them agrees with the rifle. That is the signature of an input error rather than a software error. A solver is only integrating physics; if two of them differ by a fraction of a click and both differ from your target by a full mil, the number that is wrong is one you typed.
Muzzle velocity is the usual culprit. It is measured in a test barrel with a different length, a different throat and a different lot of powder, and a hundred feet per second of error is ordinary. It hides at 200 yards and shouts at 800. Ballistic coefficient is the second, since a published figure is an average across a speed band and across a production run. Sight height is the quiet third: measure from the centre of the bore to the centre of the scope tube, not to the bottom of the bell.
None of that is fixed by finding a better calculator. It is fixed by shooting a group at a known distance and telling the calculator what happened, which is what the truing box above is for.
Frequently asked questions
How accurate is a ballistic calculator?
The maths is exact; the inputs are not. A solver integrates the same equations every tool uses, so two honest calculators agree with each other closely. What they cannot know is your actual muzzle velocity, your actual ballistic coefficient, and how your scope actually tracks. Those errors stay invisible up close and grow with distance, which is why a solution that looked perfect at 300 yards can be a full mil out at 800. Treat the output as a starting point, then confirm it on paper or steel and correct the tool with what the rifle did.
Why does my ballistic calculator not match my real drop?
Almost always because the muzzle velocity or the ballistic coefficient you entered is not the one your rifle produces. Box velocities are measured in test barrels, not yours, and advertised coefficients are averages. Scope height over bore is the other common entry error, and at long range a scope that does not track its dial exactly adds to it. The fix is truing: shoot a known distance, enter what actually happened, and let the solver work backwards to the velocity that would have produced it.
What is truing a ballistic solution?
Truing means correcting the inputs until the prediction matches observed reality. You shoot at a distance far enough for drop to be meaningful, record the come-up you actually needed, and then adjust muzzle velocity until the calculator reproduces it. From that point the solution is fitted to your rifle, your ammunition and your conditions rather than to a catalogue number. It is the single step that separates a calculator that agrees with your DOPE from one that does not.
Should I use a G1 or G7 ballistic coefficient?
Use whichever one your bullet maker published, and never mix them up, because the same bullet has very different numbers on the two scales. G1 is referenced to a flat-base projectile and is the figure most catalogues print. G7 is referenced to a boat-tail shape that resembles a modern long-range bullet much more closely, so a G7 coefficient stays more constant across the speed range and usually gives a better answer past several hundred yards. A G7 value is roughly half its G1 equivalent, so entering one in place of the other produces a wildly wrong trajectory rather than a slightly wrong one.
Does temperature and altitude really change bullet drop?
Yes, through air density. Hot, high air is thinner, so the bullet is slowed less and drops less; cold air at sea level is denser and costs you more. The effect is small at short range and substantial past several hundred yards, which is why a solution trued at home can be wrong on a mountain. Enter the temperature and altitude you are actually shooting in rather than the ones you sighted in at.
What does this calculator not account for?
Spin drift, Coriolis, aerodynamic jump and the effect of powder temperature on muzzle velocity are not modelled. They need inputs most shooters cannot supply accurately, such as twist rate, latitude and firing azimuth, and including them with guessed values would make the answer look more precise without making it more correct. At the distances where those effects become significant you should be trueing against real data anyway.
Related: MOA / MRAD adjustment calculator · mil dot ranging calculator · MOA vs MRAD · how to sight in a rifle scope · FFP vs SFP.