Basics
What does FuelCalc do?
It converts aviation fuel between kilograms, pounds, litres, US gallons, and imperial gallons at a real density, plans fuel required with reserve presets, works out endurance and range, and runs three ramp checks: tankering, receipt check, and fuel weight. An aircraft profile fills in tank sizes, tabs, and typical burn so you type less.
Which devices does it run on?
iPhone and iPad on iOS 17 or later, and Android phones and tablets. On iPad and larger tablets the layout adds a sidebar and a quick converter next to the calculators.
Does it work offline?
Yes. Nothing in the app needs a connection. Everything is calculated on the device.
I had AvFuel Converter installed. Is this the same app?
Yes. FuelCalc is the same listing with a new name and a rebuilt interface. Updating from the store keeps your place on the device; you do not need to reinstall.
How much does it cost?
FuelCalc is free, with no account, no subscription, and no advertising.
Units and density
Why does the app ask about density at all?
Weight and volume are only linked through density, and density changes with fuel type, batch, and temperature. Converting 1,000 lb of Jet A to litres can differ by several percent depending on the density you use, which matters for weight and balance and for what you actually order from the truck.
Where do the default densities come from?
Each fuel has a standard density at 15 °C: 0.720 kg/L for Avgas 100LL, 0.740 for mogas, 0.820 for Jet A, 0.800 for Jet A-1 and JP-8, and 0.760 for Jet B. The value in use and its reference condition are always shown on the Convert screen.
How do I use the density printed on my fuel slip?
On Convert, tap Edit next to the density, choose From fuel slip, and type the value. Every conversion and calculator then uses that figure until you change it.
What does Adjust for OAT do?
It corrects the standard 15 °C density for the outside air temperature you enter, using the usual per-degree coefficient for gasoline or kerosene. It is a reasonable estimate when you do not have a slip value, not a replacement for one.
Why did my numbers change when I switched units?
Switching the unit on Convert converts the current and target figures so the physical quantity stays the same. The fuel is not changing, only how it is expressed.
Can I see more decimal places?
Yes. The Decimals toggle on any result card switches between whole numbers and two decimals. The same setting is in Settings.
Aircraft profiles
What goes in a profile?
Registration, type, fuel type, default unit, tabs, typical burn, and each tank's usable fuel and arm. You can add as many tanks as the aircraft has.
What do profiles change elsewhere in the app?
Convert gets To tabs and Full shortcuts. Plan and Burn start from the typical burn rate. Fuel weight splits fuel across tanks by their usable capacity and uses each arm for the moment. Receipt check and Tankering use the total usable fuel to check what fits.
Can I keep several aircraft?
Yes. Add as many as you fly and switch between them from the Aircraft tab. One can be marked as the default in Settings.
Where do I find tank arms?
In the weight and balance section of the POH or the aircraft's equipment list. Arms are optional; without them, Fuel weight still gives pounds per tank but no moment.
Planning and reserves
How is fuel required calculated?
Taxi and run-up is a fixed quantity. Trip, alternate, and reserve are minutes multiplied by the burn rate. Contingency is a percentage of trip fuel. The total is shown line by line in weight and volume, and the fuel to add is the total minus what is on board.
Which reserve presets are included?
FAR 91.151 day and night for VFR, FAR 91.167 for IFR, and the EASA final reserve for VFR and for IFR. Each sets the reserve minutes with one tap. You can always type your own figure.
What does Burn show?
Endurance in minutes and range in nautical miles from fuel on board, burn rate, and groundspeed, with the reserve you set held back and shown separately. The Fuel for a leg tab works the other way: time or distance in, fuel out.
Is this a substitute for the POH or my operator's fuel policy?
No. FuelCalc does arithmetic on the numbers you give it. Performance figures, legal minimums, and company policy come from the POH, the regulations, and your operator. Check the result against those before you fly.
Tools
How does Tankering decide?
You enter the price here, the price at the destination, the fuel you would carry extra, and a carry penalty as a percentage of that extra fuel burned by carrying it. The app compares the cost of each option, shows the saving, and checks that the extra fuel fits in the tanks.
What does Receipt check compare?
Delivered against ordered, gauge change against delivered, and slip density against the standard for that fuel. Each line is flagged against a tolerance so a mis-keyed slip or a short delivery stands out.
What is Fuel weight for?
It turns the fuel on board into pounds and moment per tank for the weight and balance, using the profile's tank arms.
Your data and privacy
Where is my data stored?
Only on your device. There is no account, no sync, no analytics, and no network traffic from the app.
How do I delete my data?
Settings has a Clear history button for conversions and plans. Aircraft can be deleted from their edit screen. Uninstalling the app removes everything.
Will my aircraft and history move to a new phone?
Only if your platform's device backup restores app data, which iCloud and Google backups normally do. There is no cloud account to sign into.
Contact
How do I report a problem or suggest a feature?
Email hello@blackmountainig.com. For a bug, say what you entered, what you expected, and what you got. The app version is at the bottom of Settings. There is also a Send feedback link there that opens an email with the subject filled in.