The premier API fuel gravity calculator for fuelers, technicians, and FBOs. Enter your observed API gravity and temperature, pick a fuel type, get the corrected value at 60°F instantly, with a hands-free Apple Watch companion app for calculations out on the ramp.
AvGrav is the modernized, field-ready API fuel gravity calculator designed specifically for aviation line service technicians, FBO operations, and quality assurance personnel. Built from the ground up, AvGrav delivers instant, precise fuel density calculations right on your phone. Whether you're handling Jet-A, 100LL, Mogas, or Diesel, AvGrav calculates all your needs, using standard, publicly verified API MPMS Chapter 11.1 / ASTM formulas to determine corrected API gravity at 60°F (15°C).
No subscription, no in-app purchases, no ads.
The world clock built for aviation and AvGeeks alike — track local time, UTC/Zulu, live weather, and airport status for any airport on Earth, beautifully and at a glance.
No — the correction math is the same for every fuel type in the app. Jet A, 100LL, Mogas, and Diesel are all light, refined petroleum products, so they all use the same standard correction table. What changes per fuel type is the normal reading range, not the equation.
No. AvGrav is a reference and convenience tool, not a substitute for a calibrated physical hydrometer, thermometer, or your organization's official fuel-acceptance procedures. Always confirm results against official procedures before an acceptance or rejection decision.
No. AvGrav is a single one-time purchase. No recurring charges, ever.
No. AvGrav makes no network requests at all. There are no accounts, no analytics, and nothing is ever transmitted anywhere — every calculation and every photo stays on your own device.
Yes, a full Watch app with its own calculator, history, and a complication that launches straight into a new reading. It currently keeps its own separate history from the iPhone app.