Aircraft fuel weight: converting Jet A gallons to pounds for weight and balance
A student pilot I was mentoring pulled a fuel weight straight off an avgas density chart for a Jet A-powered aircraft, and the weight and balance came out wrong because the two fuels have noticeably different densities.
We write the way we argue on the bench: exact factor, one sharp trap, one worked example you can re-check.
A student pilot I was mentoring pulled a fuel weight straight off an avgas density chart for a Jet A-powered aircraft, and the weight and balance came out wrong because the two fuels have noticeably different densities.
Here is the conversion I wish I had taped to the fridge before that went sideways.
The factor that settles arguments
This is the relationship our converters use. Screenshot it if you have to — just stop re-deriving it from a half-remembered blog post.
Jet A ≈ 6.7 lb per US gallon (typical, temperature-dependent)
Write that line once at the top of your notes. Every later arithmetic step should point back to it instead of inventing a friendlier number mid-stream.
The mistake that keeps showing up
Using an avgas density figure (about 6.0 lb/gal) for a Jet A calculation, or vice versa — the two fuels aren't interchangeable in weight and balance math despite both being measured in gallons.
I still write the unit next to every intermediate value. It looks pedantic until it catches the one swap that would have shipped wrong.
- Write down the known value in US gallons of Jet A.
- Confirm the target unit is really lb, not a similar-looking one.
- Apply the factor: Jet A ≈ 6.7 lb per US gallon (typical, temperature-dependent).
- Round only at the end, to the precision your tool or spec supports.
Worked example
A fuel truck loads 1,000 US gallons of Jet A, and you need the weight for a weight and balance calculation.
1000 US gallons of Jet A × 6.7 = 6700 lb
That's 6700 lb — round only to the precision your tool or spec actually needs.
I usually convert once, write the answer with units, then convert back. That two-step habit has saved more weekends than any fancy app.
Quick reference table
| US gallons of Jet A | Calculation | lb |
|---|---|---|
| 1 | 1 × 6.7 | 6.7 |
| 2 | 2 × 6.7 | 13.4 |
| 5 | 5 × 6.7 | 33.5 |
| 10 | 10 × 6.7 | 67 |
Use the table for speed once you trust the factor. Do not use it as a substitute for understanding which definition of the unit you are on.
Why the exact number matters
Weight and balance calculations directly affect an aircraft's center of gravity and safe operating limits — using the wrong fuel density skews every number downstream.
Precision is not about showing off decimals. It is about making sure the shopping list, the machine setting, and the acceptance check are all describing the same physical quantity.
Pocket recap
Multiply gallons by approximately 6.7 lb/gal for Jet A — 1,000 gallons weighs about 6,700 lb, and always check the actual density for the day's temperature on a precise load sheet.
Keep the converter link nearby for the next time the same debate shows up in a group chat. Re-typing the factor from memory is how the wrong cousin of a unit sneaks back in.
Try the converters mentioned in this article
FAQ
What is the exact US gallons of Jet A to lb factor here?+
Jet A ≈ 6.7 lb per US gallon (typical, temperature-dependent)
Should I round partway through the calculation?+
No — carry full precision through the multiplication and round only the final answer, to the precision your tool, gauge, or spec actually supports.
What's the single biggest mistake people make with this conversion?+
Using an avgas density figure (about 6.0 lb/gal) for a Jet A calculation, or vice versa — the two fuels aren't interchangeable in weight and balance math despite both being measured in gallons.
This article was written by The Turbo Unit Converter engineering desk (Applied units & field metrology) and last reviewed on 2026-07-17 against NIST SP 811 and the BIPM SI Brochure. Read our full editorial policy.