GenRun: Generator RuntimeGenRun: Generator Runtime
Fuel hours left in the genset, and the time of day you will need to refuel.
Download on the App Store
Screenshots
Features
Hours that track what you have running
Runtime is never a set figure. Put in your genset's tank size and rated output, tick off what is plugged in, and GenRun estimates the hours left in the tank as the load moves around.
Tells you when, not just how long
Alongside the hours remaining you get the time of day the next refuel falls due, which is a lot easier to work a day around than a bare countdown.
Countdown that lives on the Lock Screen
A Live Activity keeps the time remaining on your Lock Screen and sings out while fuel is still in the tank, so the genset shuts down when you say so and not at 3am in the middle of a blackout.
Fuel use worked out the honest way
Rated hours divided by load percentage makes a lightly loaded machine look far better than it is, because friction, cooling and windage keep drinking no matter what you unplug. GenRun uses a no-load loss plus a load-proportional term.
Picks up the habits of your own machine
Note down a few real refuels and the app works out what your genset actually burns. A unit that has done a few seasons on a dusty block does not match the figure on the sticker.
Petrol, diesel and bottled LPG
Litres or gallons, whichever you are used to. Gas bottles are handled by weight in kilograms, the way they are swapped and refilled. Comes with a home screen widget. iPhone only.
A generator's runtime is not a fixed number. It depends on how hard the engine is working, and that changes every time somebody plugs something in.
GenRun takes your genset's tank size and rated output, adds up what you have running, and estimates how many hours the fuel in the tank is good for — plus the clock time you will need to refuel.
THE MATHS EVERYONE ELSE GETS WRONG
The common shortcut is rated runtime divided by load percentage. At a quarter load that says you are set for the night. You are not. An engine spends a big slice of its fuel just turning over — friction, cooling, windage — and none of that disappears when you unplug things. On a typical portable genset the proportional method can overstate light-load runtime by more than 200%: 38 hours claimed where the real answer is around 12.
GenRun models fuel use as a no-load loss plus a load-proportional term, which is how engines actually behave.
A RANGE, BECAUSE A SINGLE NUMBER LIES
The biggest error is not in the arithmetic, it is in guessing what your appliances actually draw. GenRun shows a range instead of a falsely confident figure. Wide range, go and check something. Narrow range, you are good.
LOCK SCREEN COUNTDOWN
A Live Activity keeps the countdown on your Lock Screen and warns you while there is still fuel left, so the genset stops when you decide — not at 3am in the middle of a blackout.
IT LEARNS YOUR GENSET
Log three or more real refuels and GenRun works out your machine's own burn rate. Engines drift away from the manufacturer's number as they age, and a genset that has done a few seasons on a dusty block is not the machine it was new.
FUELS AND UNITS
Petrol, diesel and LPG. Gas bottles are tracked by weight in kilograms, the way they are actually sold and refilled, rather than being forced into litres.
CARBON MONOXIDE
The first launch shows a full-screen carbon monoxide warning that cannot be skipped. Generators run outdoors only, well away from windows and doors — never in a shed, garage, under a patio roof or in a caravan annexe, even with everything open.
PRACTICAL NOTES
Every figure is an estimate to help you plan a refuel, not a guarantee. Check the tank yourself. Shut the engine down and let it cool before you refuel, and follow the manufacturer's instructions.
PRIVACY AND PRICE
No sensors, no account, no network. Everything stays on your iPhone. One payment, no subscription, no in-app purchases, no ads.
Handy through storm season and bushfire outages, out bush with a caravan or camper, on a remote property, on a work site, or anywhere a small engine is the only thing keeping the lights on.