⛽ Generator Fuel Tank Size Calculator
Calculate the exact fuel tank capacity needed for your generator runtime requirements
| Generator Size | Fuel Type | GPH @ 25% | GPH @ 50% | GPH @ 75% | GPH @ 100% |
|---|---|---|---|---|---|
| 1 kW | Gasoline | 0.06 | 0.09 | 0.13 | 0.17 |
| 2 kW | Gasoline | 0.10 | 0.16 | 0.22 | 0.29 |
| 3.5 kW | Gasoline | 0.17 | 0.28 | 0.40 | 0.50 |
| 5 kW | Gasoline | 0.24 | 0.37 | 0.55 | 0.73 |
| 7 kW | Gasoline | 0.34 | 0.53 | 0.77 | 1.02 |
| 8 kW | Diesel | 0.28 | 0.45 | 0.65 | 0.87 |
| 10 kW | Gasoline | 0.48 | 0.74 | 1.07 | 1.42 |
| 10 kW | Diesel | 0.35 | 0.55 | 0.80 | 1.06 |
| 12 kW | Propane | 0.79 | 1.24 | 1.79 | 2.38 |
| 15 kW | Diesel | 0.52 | 0.82 | 1.19 | 1.59 |
| 20 kW | Propane | 1.31 | 2.07 | 2.99 | 3.97 |
| 20 kW | Diesel | 0.70 | 1.10 | 1.59 | 2.11 |
| Application | Generator Size | Typical Runtime | Rec. Tank Size | Fuel Type |
|---|---|---|---|---|
| Inverter / Camping | 1–2 kW | 8–12 hrs | 1–2 gal (3.8–7.6 L) | Gasoline |
| Jobsite Portable | 3–5 kW | 8–10 hrs | 4–6 gal (15–23 L) | Gasoline |
| Home Emergency | 5–8 kW | 12–24 hrs | 6–16 gal (23–60 L) | Gasoline/Propane |
| Standby Home | 10–20 kW | 48–72 hrs | 100–500 gal (380–1893 L) | Propane/Nat. Gas |
| Commercial Site | 15–30 kW | 24–48 hrs | 30–100 gal (114–380 L) | Diesel |
| Data Center / Critical | 50–200 kW | 72–168 hrs | 500–5000 gal (1893–18927 L) | Diesel |
| RV / Travel Trailer | 2–4 kW | 6–10 hrs | 3–7 gal (11–26 L) | Gasoline/Propane |
| Fuel Type | Energy Density | Gen. Efficiency | Storage Stability | kWh per Gallon | Notes |
|---|---|---|---|---|---|
| Gasoline | 132,000 BTU/gal | ~25% | 6–12 months | ~9.7 | Common, widely available |
| Diesel | 137,500 BTU/gal | ~30% | 12–24 months | ~12.1 | Most efficient liquid fuel |
| Propane (LPG) | 91,500 BTU/gal | ~25% | Indefinite | ~6.7 | Clean burn, tank storage |
| Natural Gas | 1,020 BTU/ft³ | ~25% | Pipeline / continuous | ~1.0/cf | No storage concern |
The size of fuel tank for generators changes a lot according to what you use. At many brands there are general models with 5 or 7 gallon holders that answers for the most many cases and are made from rugged metal. On the other hand for big setups like data centers or hospitals with backup power, commonly one chooses underground tanks much more big.
Talk about holding up to 1 000 gallons, designed to last the weight of the generator standing directly on it. Such heavy systems can be listed according to UL standards and built according to your precise needs.
Generator Fuel Tanks: Sizes, Rust and Easy Fixes
The quality of building at these tanks genuinely matters. Many of them are made of steel with inner lining and a built-in vent. The surface covers industrial level synthetic powder coaitng, that defends against rust and weather damage.
Here the kind of performance, that genuinely lasts over time.
About portable generators though? They usually have very little fuel tanks. For instance, one little model with double fuel weighs only 47 pounds and has a 1 gallon gas tank.
There is also an option with 1.8 gallon holding, although some online user mentioned wanting to add yet one gallon ore more. For devices between 4 000 and 8 000 watts, a fuel tank of 7 gallons answers for various brands and types.
The amount of fuel, that your generator uses, depends on two main things: the device itself and the strength of its working. A little model clearly uses less gas than a big one. But if you raise the power load, the usage grows quickly.
I saw systems with 13 gallon tanks, that run under low load for five to six days without stopping. Around 125 to 150 hours of run time on about 14 gallons, not entirely bad.
Here the problem with metal tanks: they rust. One person learnt that the hard way after four years, when he found his gas cover corroded and the inside of the fuel tank full of rust. So some prefer plastic tanks instead.
Replacing a rusted fuel tank is easy: buy a new one from online stores, measure carefully, choose the nearest size and adapt it to answer.
An outside fuel tank forms another reliable fix. The most basic way? Simply undo the fuel line from the carburetor and tie a line from the outside tank instead.
Want something more steady? A three-way valve allows flow from both tanks to the carburetor without change. Sealed covering of the generator with a vented outside fuel tank creates the needed vacuum to automatically draw fuel during the engine work.
Fuel stabilizer must be added always, when you fill the fuel tank of your generator. If the gas sat for almost half a year, simply dump it in your car andtake fresh. Some owners of dual fuel models entirely skip gasoline and use propane to get rid of the whole problem of carburetor pollution, that happens with gasoline.
