Grains vs ArrowForge

Build a better hunting arrow. Grains calculates your total arrow weight, FOC, arrow speed, kinetic energy and momentum in one simple archery calculator. Four calculators, no account, no ads, nothing to buy. Numbers carry from one tab to the next, so you enter your arrow build once. ARROW WEIGHT When you build an arrow, you're working with many small components of different weights. Enter your shaft length and grains per inch (GPI), point or broadhead, insert, nock, vanes or fletching, wrap and any additional weight, and Grains adds up your total arrow weight in grains. Change one component and see right away how it affects the whole build. FOC (FRONT OF CENTER) Front of center is an important factor in building an accurate hunting arrow. Enter your arrow length and balance point to get your FOC percentage. Grains also explains how to get an accurate measurement and what an ideal setup looks like (most hunters aim for 10% to 15%). ARROW SPEED A slow arrow gives game more time to "jump the string." Enter your bow's IBO speed, draw length, draw weight and any weight on the string, and Grains estimates your arrow speed in fps using the standard IBO rules. It also shows your grains per pound and warns you when your arrow drops below 5, the minimum most bow makers require to keep your warranty. KINETIC ENERGY AND MOMENTUM A fast arrow with good FOC is only good if it carries enough energy. Grains calculates kinetic energy in ft-lbs from your arrow weight and speed, shows the game your setup is suited for, from small game to deer, elk and black bear to moose and grizzly, and shows momentum, the number many bowhunters use to judge penetration. METRIC OR IMPERIAL Results follow your region's units, or pick your own in Settings: speed in m/s, energy in joules, momentum in kg·m/s and total weight in grams alongside grains. Inputs stay in grains, inches and pounds, just like your spec sheets. QUICK TO USE Jump between fields with the arrows at the top of the screen, tap any label to edit it, and swipe down to put the keypad away. Speed is an estimate based on IBO specs. For an exact number, chronograph your bow.

Stop guessing. Build the perfectly matched setup before you buy the parts. Max your effectiveness. ArrowForge turns the guesswork of your bow and arrow setup into clear, ballistics-grade answers. Enter your bow and arrow (or Pro users get AI recommendations), and instantly see whether your build actually works — spine, FOC, speed, kinetic energy, and lethal range — with the math explained in plain English. Experiment with modifications before you buy the parts. ArrowForge Pro is an auto-renewing subscription: $6.99/month or $39.99/year. Payment is charged to your Apple Account at purchase. It renews automatically unless turned off at least 24 hours before the period ends; manage or cancel anytime in Account Settings. Terms: https://arrowforge.app/terms · Privacy: https://arrowforge.app/privacy Built by a bowhunter, for bowhunters and archers who want to understand their setup, not just copy a chart. DIAL IN YOUR BUILD — FREE • Dynamic spine check against a multi-brand consensus — know if your specs is right before you buy • FOC, GPP, GPI, total weight, and a calibrated arrow-speed estimate • Kinetic energy & momentum at the bow and downrange • Drag-aware field-ballistics solver with an uphill/downhill shot-angle dial • Sight pins, holdover, and pin-gap planning • Pursuit Effectiveness — your lethal range by game class (deer, elk, toughest game) from real KE + momentum thresholds • Build Match Score weighted to your hunt and goal • Every number comes with a plain-English explanation of why it matters ARROWFORGE PRO — AI + THE MATH • AI bow & arrow spec lookup — type a model, get the specs • AI Arrow Recommender — purpose-built archetypes for your setup • AI Sanity Check, Build Plan, and tuning insights • The exact formula AND your step-by-step calculation behind every number AN INFORMED SECOND OPINION — NOT A SHORTCUT ArrowForge is a sanity-check, not a substitute for proper tuning by qualified bow technicians. It defers to your bow technician on spine, draw length, and setup safety, and it never tells you to take an unsafe shot. Always verify on the range and with a qualified pro before you hunt. Core calculations work offline. No ads. No data selling.