Bullet Drop Calculator
Get your bullet drop from the elevation you actually dialled, not from a bullet maker's numbers. This is gravity ballistics: drop worked out with arithmetic from confirmed hits instead of a drag model. Enter the dial that centred a group at one or more distances and you get a full range card back — every yard line, the multiplier between them, and turret clicks. No ballistic coefficient, no chronograph, no atmosphere: your hits already contain all of it.
Your confirmed data
Dial unit
Confirmed dials (MIL)
- ydMIL
- ydMIL
- ydMIL
Up to ten rows. Enter the dial that centred the group, not what a solver predicted.
Range card
| Yards | Dial (MIL) | Clicks | Factor | Residual | Source |
|---|---|---|---|---|---|
| 200 | 0.48 | 5 | — | — | interpolated |
| 300 | 1.00 | 10 | 2.08× | +0.00 | confirmed |
| 400 | 1.68 | 17 | 1.68× | — | interpolated |
| 500 | 2.50 | 25 | 1.49× | -0.01 | confirmed |
| 600 | 3.48 | 35 | 1.39× | — | interpolated |
| 700 | 4.60 | 46 | 1.32× | +0.01 | confirmed |
| 800 | 5.84 | 58 | 1.27× | — | extrapolated |
| 900 | 7.22 | 72 | 1.24× | — | extrapolated |
| 1000 | 8.73 | 87 | 1.21× | — | extrapolated |
Free charts stay here. Saved rifles and truing per rifle are on Trajek.
Where gravity ballistics runs out
- It assumes a level range and a genuinely confirmed zero.
- It assumes your confirmed dials are ballistics, not shooter error — average a group, do not chase one shot.
- The curve holds while the bullet is well supersonic. Near and past transonic, real drop outruns it.
- Uphill or downhill shots and big changes in density altitude need their own correction; neither is applied here.
- Rimfire and subsonic loads bend far too hard for this shape to fit well.
How gravity ballistics works
Most bullet drop calculators predict drop: you feed in a ballistic coefficient and a muzzle velocity, and a drag model works out where the bullet should land. Gravity ballistics goes the other way round. It measures your drop from hits you have already made, because a confirmed dial at a known distance already contains your barrel, your load on that day, your scope's true click value, the air you were shooting in and your sight height. Feed those numbers in and you get a bullet drop chart built from your rifle rather than from a bullet maker's box.
Building a bullet drop chart from real hits
Work near to far. Confirm your zero first — everything downstream leans on it. Then take the furthest distance you can shoot confidently, usually 300 yards, dial what the card says, fire a group and correct until it is centred on the waterline. Write down the dial that did it, not the one you started with. Enter it here and the calculator gives you a multiplier to the next yard line: multiply your confirmed dial by it, dial that, shoot, correct, and record the corrected value as a new row. Each row you add sharpens the drop curve behind every other distance on the card.
Two confirmed distances set well apart are enough to pin the shape of your bullet drop. Three or four across the range you actually shoot is better, and once you have several rows the residual column starts earning its keep: a row that disagrees with the fit by more than your group size is usually a mistyped number, a windy string, or a bad zero rather than a real ballistic surprise. Delete it, reshoot it, and see whether the fit settles.
Read the source column before you trust a row. Confirmed rows are your hits. Interpolated rows sit between two confirmed distances and are the most reliable predictions the method makes. Extrapolated rows sit past your furthest hit — treat those as a first dial to shoot from, never as data, because drag climbs steeply as the bullet slows towards transonic and the curve will under-call elevation out there.
Gravity ballistics is a method, not a product. It is the arithmetic behind the range-card drills taught in precision rifle classes, where a shooter with no solver and no chronograph still builds usable elevation data in an afternoon. The difference here is that the multipliers come from your own confirmed rows rather than from a generic table, so they carry your rifle's actual behaviour instead of an average of somebody else's.
Keep the card honest as conditions change. A big move in altitude or temperature, a new lot of powder, or a fresh barrel all shift your bullet drop, and the fastest way to catch it is to reconfirm one distance in the middle of your band. If it has moved, update that row and let the rest of the card follow.
Want a physics-based prediction alongside your measured drop? The bullet trajectory calculator solves a full flight path from a ballistic coefficient and muzzle velocity, and the printable DOPE card adds wind holds to it. Comparing a predicted curve against your gravity ballistics card is a fast sanity check on both.
Questions shooters ask
- What is gravity ballistics?
- Gravity ballistics is the plain-arithmetic way of describing bullet drop: instead of modelling drag from a ballistic coefficient, you treat gravity's effect on your dial as a curve you can measure directly from confirmed hits. Because drop in angular units grows by a steady multiplier between yard lines, one or two confirmed dials describe the whole curve. That is exactly what this gravity ballistics calculator does — it reads your confirmed elevation and prints the rest of the card.
- How do I work out my bullet drop without a ballistic coefficient?
- You use the dial values you already confirmed on paper. Once a hit is centred at a known distance, that dial is ground truth for your rifle, load, scope and conditions on the day. Two or more confirmed distances describe the shape of your bullet drop curve, so the calculator can fill in the distances between them and carry the curve a little further out. No ballistic coefficient, muzzle velocity or atmosphere is entered, because your hits already contain all of it.
- What is the X factor and how does the multiplier method work?
- Between any two yard lines your dial grows by a fixed multiplier — dial at the far line divided by dial at the near line. Shooters use it near to far: confirm 300 yards, multiply to get a starting dial for 400, shoot, correct, then multiply again from the corrected 400. This tool prints that multiplier for every step of your card, derived from your own confirmed data rather than a generic table.
- How many yard lines do I need to shoot to build a full drop chart?
- One confirmed distance plus your zero already produces a usable starting card, but the exponent is assumed rather than measured. Two confirmed distances that are well apart — say 300 and 700 yards — pin the shape properly. Three or four spread across the range you actually shoot is the sweet spot, and every extra confirmed row tightens the fit and exposes a bad data point.
- Can this work in MOA instead of MILs?
- Yes. Pick your dial unit at the top and enter your data in that unit. The fit is identical either way — only the numbers on the card change — so a MOA shooter and a MIL shooter with the same rifle get the same curve.
- How accurate is gravity ballistics past my furthest confirmed shot?
- The multiplier is steady while the bullet is comfortably supersonic. As it slows towards transonic, drag rises sharply and drop grows faster than the curve predicts, so gravity ballistics under-calls elevation at the far end. That is why rows beyond your furthest confirmed shot are flagged as extrapolated — treat them as a starting dial to be confirmed, not as data.