Jet A Gravity Calculator — Correct API to 60 °F

Every Jet A delivery is a quality decision. You are not just topping tanks — you are accepting fuel that has to meet spec, match what you ordered, and match what you will sign for on the receipt.

Why temperature matters

Hydrometers read observed API gravity at whatever temperature the sample is in the bucket or test jar. Contracts, receipts, and quality checks usually reference corrected API at 60 °F. Without correction, a warm summer sample can look better than it really is, and a cold morning sample can look worse.

Use the calculator above with:

• Observed API from the hydrometer in the sample
• Fuel temperature from the thermometer in the same sample

The tool applies the customary API MPMS Chapter 11.1 / ASTM D1250 correction (including the glass hydrometer adjustment from ASTM D1298). Nothing is saved — it is a field reference, same as the Gravity Check tool inside Flight Record for logged-in fuel programs.

Typical Jet A range

Most Jet A deliveries land in a familiar corrected API band. If your result is far outside that band, treat it as a stop-and-verify moment:

• Re-read hydrometer and thermometer
• Confirm the sample is representative (not foam, not water at the bottom)
• Hold the load if contamination is suspected

Document what you measured. That paper trail matters when a customer, FBO, or internal audit asks what you accepted.

Where this fits in operations

Gravity is one line on a fuel event, but it connects to bigger operational habits:

• Inventory — knowing density helps reconcile gallons vs. weight
• Billing — customer fuel charges should match what you accepted
• SMS — repeated out-of-spec fuel is a hazard signal worth reporting

Flight Record ties fuel logging, equipment, aircraft, and SMS in one system so fuel quality is not a sticky note on a clipboard.

Next steps

If you run fuel at multiple bases or trucks, see how Flight Record features connect fuel, fleet, and reporting — or book a demo for a walkthrough tailored to your operation.