Bullet Drop and External Ballistics Calculator
Calculate bullet drop, time of flight, and velocity at range for any caliber.
Find scope correction in MOA or mils for long-range shooting based on muzzle velocity and ballistic coefficient.
External Ballistics External ballistics covers the flight of a projectile after it leaves the barrel. Gravity constantly accelerates the bullet downward at 9.81 m/s². The bullet drops below the line of bore, not the line of sight. A scope sits above the bore — the bullet crosses the line of sight twice (near zero and far zero).
Simplified Drop Formula (no air resistance) Drop (vacuum) = ½ × g × t² Where t = time of flight = range / muzzle_velocity (approximation without drag). In reality, air drag slows the bullet and increases time of flight, increasing drop.
G1 Ballistic Coefficient The BC (G1) measures how efficiently a bullet retains velocity against drag. Higher BC = less drag = less drop. Typical G1 BCs: .22 LR: 0.13–0.16 | .308 168gr: 0.475 | 6.5 Creedmoor 147gr: 0.697 .338 Lapua 250gr: 0.587 | .50 BMG 750gr: 0.950
Approximate Trajectory with Drag (Pejsa model) This calculator uses a simplified atmospheric drag model for practical field use. For precision long-range work, use Hornady 4DOF or Applied Ballistics software.
Scope Adjustment MOA (Minute of Angle): 1 MOA ≈ 1.047 inches at 100 yards (close enough to 1 inch). MRAD (Mil-radian): 1 mil = 10 cm at 100 m = 3.6 inches at 100 yards. Convert drop to MOA: MOA = drop_inches / (range_yards / 100) Convert drop to mils: mils = drop_cm / (range_m / 10)
Zero Range A typical 100-yard zero means the bullet is at the same height as the crosshair at 100 yards. The bullet is typically 1.5" high at 50 yards (for a 100-yd zero). Long-range shooters often use a 200-yard zero to minimize mid-range correction.