What Is the Bullet Drop Ballistic Calculator?
This calculator estimates how far a bullet falls between the muzzle and the target using the physics of gravity. You enter your muzzle velocity, distance to the target, and the range you zeroed at, and it returns an approximate drop along with the sight adjustment needed to correct it. The core idea is simple: the longer a bullet is in the air, the more gravity pulls it down, and that time in the air is set by how fast the bullet leaves the barrel. It is a clear, physics-first way to understand trajectory before you ever dial a scope.
A Worked Example at 300 Yards
Suppose you are shooting at 300 yards — that is 900 feet — with a bullet leaving the muzzle at 2,800 fps. First find the flight time: t ≈ 900 ÷ 2,800 ≈ 0.32 seconds. Then apply free fall: drop ≈ ½ × 32.2 × 0.32² ≈ 1.65 feet, or about 20 inches, before you account for your zero. Zeroing at, say, 100 yards shifts that figure so the drop is measured from your point of aim. Keep in mind this is the gravity-only answer. Real bullets shed velocity to air drag the whole way downrange, so the true drop at 300 yards is noticeably more — accurate numbers need the bullet's ballistic coefficient and a proper drag model.
Why Zero Range Changes Everything
Bullet drop is only meaningful relative to where your sights are set. Because the bore sits below and tilts up toward the line of sight, the bullet crosses your aiming line twice: once on the way up and again coming down at your zero range. Inside the zero the bullet can print slightly high; past it, the drop you have to hold for grows quickly. That is why the same cartridge behaves very differently with a 100-yard zero versus a 200-yard zero, and why every honest drop number has to state the zero it was measured from.
Bullet Drop Calculator
How to Use This Calculator
- Enter Your Muzzle Velocity (fps): Use the velocity from your ammo box or, better, a chronograph reading for your rifle. This drives the flight time and has the largest effect on drop.
- Add Ballistic Coefficient and Distance: Enter the bullet's BC and the distance to your target in yards. Distance sets how long gravity has to act; BC describes how well the bullet fights drag downrange.
- Set Your Zero Range: Enter the distance your rifle is sighted in at — commonly 100 or 200 yards. Drop is always reported relative to this zero, so it matters as much as any other input.
- Calculate and Read the Holdover: Hit Calculate to see the estimated drop and the matching sight adjustment. Use it to plan a hold or a dial, then confirm the real value on paper at the range.
How It Works
The moment a bullet leaves the muzzle, gravity begins pulling it toward the earth at the same 32.2 ft/s² it pulls everything else. This calculator estimates how far the bullet falls over a given distance by working out the flight time from your muzzle velocity, then applying the physics of free fall — and correcting that fall for the range you zeroed your rifle at.
The basic rule:
- Simple Drop — Drop = ½g × t² (adjusted for zero range) — Gravity acts on the bullet for the entire flight, so drop grows with the square of time in the air. Sighting in at your zero range removes the drop at that one distance and shifts everything else relative to it.
This is a gravity-only model. It ignores air drag, which is the single biggest factor in real trajectories, so treat the numbers as a teaching estimate rather than a dope card for the range.
Tips & Considerations
- Chronograph your actual load if you can — a 100 fps error in muzzle velocity meaningfully changes the flight time and the drop, especially past 300 yards.
- Always note the zero range next to any drop figure. '20 inches of drop' means nothing until you say whether it is from a 100- or 200-yard zero.
- Match your turret units to your reticle. Dialing MOA while holding off a mil reticle (or vice versa) is a common way to miss under time pressure.
- Remember this model is gravity-only, so it under-predicts real drop. Treat it as a floor and expect the true holdover to be larger once drag is included.
- Verify your solution on paper. Build a dope card by shooting at known distances and compare it to any calculator before trusting a long-range hold.
Frequently Asked Questions
What actually causes bullet drop?
Gravity. From the instant the bullet clears the barrel it is in free fall, accelerating downward at 32.2 ft/s² regardless of how fast it is traveling forward. A bullet does not fly level and then dip — it starts falling immediately. The reason a fast bullet appears to shoot 'flatter' is only that it reaches the target sooner, so gravity has had less time to work on it.
What is zeroing a rifle?
Zeroing (or sighting in) is adjusting your sights so the bullet strikes exactly where the crosshair points at one chosen distance — the zero range. Because the barrel is tilted slightly upward relative to the line of sight, the bullet crosses your sight line on the way up, peaks, and crosses it again coming down at the zero distance. Past the zero the bullet drops below your point of aim, which is the holdover you have to account for.
Why does muzzle velocity matter so much?
Velocity sets the flight time, and drop depends on the square of that time. A faster bullet spends less time exposed to gravity before reaching the target, so it drops less. Roughly, flight time equals distance divided by velocity — bump the muzzle velocity up and the same target is reached quicker, shrinking the drop. This is why load developers and reloaders chase consistent, higher velocities within safe pressure limits.
What is the difference between MOA and mil?
Both are angular units for dialing your scope. One MOA (minute of angle) subtends about 1.047 inches at 100 yards — near enough to 1 inch that shooters round it. One mil (milliradian) subtends 3.6 inches at 100 yards, or 3.6 inches per 100 yards at any range. Neither is more accurate; they are just different rulers. Match your scope's turrets to its reticle — mil/mil or MOA/MOA — so a holdover you see in the reticle equals the clicks you dial.
Why do real ballistics need the ballistic coefficient?
This calculator's simple model assumes only gravity acts on the bullet, but in reality air drag is constantly slowing it down, which increases flight time and therefore increases drop beyond the gravity-only figure. The ballistic coefficient (BC) is a number describing how well a bullet's shape and weight let it resist that drag — a higher BC means less velocity lost and less drop. Accurate long-range solutions require BC plus a drag model (like G1 or G7), which is why a serious dope card comes from a full ballistic solver or verified field data.
What affects bullet drop?
Muzzle velocity and distance drive the gravity-only drop. In the real world, air drag, ballistic coefficient, altitude and air density, temperature, and even the shooting angle all change the trajectory, and wind pushes the bullet sideways rather than down.