Tools
Reloading calculators
Quick math for the loading bench. Bookmark this page — and if there's a calculator you wish existed, tell us and we'll build it.
Recoil
Free recoil energy, recoil velocity and impulse for rifle, handgun and shotgun loads, with presets and a plain-English read on what the number feels like. Open the calculator →
Twist rate & bullet stability
Miller stability factor for your bullet in your barrel, corrected for velocity, temperature and altitude, plus the twist it would take for full stability. Pick a bullet from the cartridge reference or type your own. Open the calculator →
Power factor calculator
Power factor = bullet weight (grains) × velocity (fps) ÷ 1,000. Common floors: USPSA Minor 125, Major 165 (Open Major 160). Always confirm against the current rulebook for your sport and division.
Makes USPSA Minor (125+). Below Major floor.
Charge window calculator
Set a target charge and the +/− tolerance you want to allow, and see the acceptance window your powder check needs to hold — and how far outside it a double charge lands.
A double charge (8.40 gr) sits 4.10 gr above your window — any functioning check catches it. The hard part is the partial undercharge just below 4.10 gr: catching that reliably is where measurement resolution matters.
Cost per round
What a loaded round actually costs, using powder, bullet, primer and brass prices collected from retailers this morning. Pick your cartridge, type the charge weight you load, and it fills in the rest — cheapest in stock first, with a link to every listing it used. Open the calculator →
Related reading
How tight can a powder check actually hold that window? See our honest comparison of every powder check system and the squib prevention guide. Our laser powder checks hold windows at micrometer-level resolution and stop a Mark 7 Autodrive automatically.