NORTH AMERICA
US Liquid Gallons
3.785 L per gallon. Machinery, fuel, and tank specs use this standard across the US and Canada.
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Fuel Conversion Basics
What Is Liters per Hour to Gallons per Hour Conversion?
Liters per hour to gallons per hour conversion changes a volumetric flow rate from the metric unit L/h to the imperial-unit gallon per hour, written GPH. On spec sheets and fuel orders this is the L/h to gal/h conversion, and it answers a practical question: a machine spec says 25 liters per hour, and the fuel order is placed in gallons. One rate, two unit systems, one conversion.
Formula
US Gallons per Hour
gal/h (US) = L/h × 0.2641721
100 L/h = 26.42 US gal/h
Formula
Imperial Gallons per Hour
gal/h (UK) = L/h × 0.2199692
100 L/h = 22.00 UK gal/h
Reverse
Gallons to Liters
L/h = gal/h (US) × 3.7854
L/h = gal/h (UK) × 4.5461
Worked Example — 200 kW Diesel Generator
A 200 kW genset at full load burns about 64.8 L/h.
US gallons: 64.8 × 0.2641721 = 17.12 US gal/h
Imperial gallons: 64.8 × 0.2199692 = 14.25 UK gal/h
A generator's fuel burn is specified in L/h by the manufacturer, budgeted in gal/h by the buyer, and ordered in liters or gallons depending on the market. The calculator holds all four numbers in one result card so nobody has to redo the math at a fuel terminal.
Why It Matters
The 20% Difference That Changes Everything
01
Two Gallons, Two Sizes
The US gallon holds 3.785 liters. The Imperial gallon holds 4.546 liters — about 20% larger. That one difference changes every conversion result.
02
Same Flow, Different Numbers
100 liters per hour is 26.42 US gallons, but only 22.00 Imperial gallons. The same flow, two different numbers — depending on which standard your supplier uses.
03
Get It Wrong and You Undersize Your Tank
Choosing the wrong gallon standard can undersize your fuel tank by one-fifth. That mistake only shows up when the generator runs dry — and you're out of fuel.
04
Check Your Supplier's Standard
A gallons-per-hour figure without a US or UK label is a red flag. Always confirm which gallon standard your fuel order uses before you size a tank.
L/h to GPH Converter
Liters per Hour to Gallons per Hour Calculator
Convert liters per hour to gallons per hour (US & UK) and back. Dual-standard conversion with both directions, NIST-defined gallon factors.
Enter Your Flow Rate
Select the direction, enter a value, and choose your gallon standard. The calculator returns both US and Imperial results.
Quick Conversion Table
Liters per Hour to Gallons per Hour Conversion Table
For quick lookups without the calculator, here are the common rates already converted to both standards. The table covers the flow range that matters most for generator fuel and industrial pumps.
| Liters per Hour (L/h) | US Gallons per Hour | Imperial Gallons per Hour |
|---|---|---|
| 1 | 0.26 | 0.22 |
| 5 | 1.32 | 1.10 |
| 10 | 2.64 | 2.20 |
| 20 | 5.28 | 4.40 |
| 50 | 13.21 | 11.00 |
| 75 | 19.81 | 16.50 |
| 100 | 26.42 | 22.00 |
| 150 | 39.63 | 33.00 |
| 250 | 66.04 | 54.99 |
| 500 | 132.09 | 109.98 |
Quick mental check: liters per hour × 0.264 = US gallons per hour, or ÷ 4 for a rough estimate (the ÷ 4 shortcut is within 6% of exact). A 200 kW set burns about 65 L/h at full load; a large 1 MW plant burns over 300 L/h. If your rate sits between rows, the calculator interpolates exactly.
Gallon Standards
US Gallons vs Imperial Gallons: Which Do You Need?
The US liquid gallon equals 3.785 liters; the Imperial (UK) gallon equals 4.546 liters, the standards NIST defines in Handbook 44. A US gallon is about 20% smaller than a UK gallon, so a given flow in liters per hour produces fewer Imperial gallons per hour than US gallons per hour.
UK & COMMONWEALTH
Imperial Gallons
4.546 L per gallon — about 20% larger. Used in the UK, Ireland, and most Commonwealth countries. Fuel is now mostly sold by the litre, but older machinery still uses Imperial gallons.
DIESEL TRADE
Check Your Supplier
A quoted "gallons per hour" figure without a US/UK label is a red flag. Confirm the standard before you size a tank or order fuel.
The 20% Spread
A Site Burning 100 L/h — Wrong Standard = 106 Gallons/Day Error
A site burning 100 L/h that assumes the wrong standard is off by about 4.4 gallons per hour, roughly 106 gallons over a day of continuous running. That is a tank-sizing error, not a math error. Our calculator returns both standards on every conversion so you can compare at a glance. That is why a liters per hour to gallons per hour converter that never hides the second standard is the only kind worth using on a fuel budget.
Flow Conversions
Liters per Minute to Gallons per Hour & Other Conversions
Pumps and spray systems usually rate flow in liters per minute, not liters per hour. Convert L/min to L/h first (multiply by 60), then your liters per hour to gallons per hour result follows.
| Conversion | US Gallons | Imperial Gallons |
|---|---|---|
| L/min → GPH | × 15.8503 | × 13.1982 |
| L/h → GPM | × 0.00440287 | × 0.003666 |
| gal/h → L/h | × 3.7854 | × 4.5461 |
| L/min → L/h | × 60 | |
Worked Example
A Water Pump Delivers 20 L/min
US gallons per hour: 20 × 15.8503 = 317 US gal/h
Imperial gallons per hour: 20 × 13.1982 = 264 UK gal/h
Fuel Budget
From Gallons per Hour to Fuel Budget
Converting liters per hour to gallons per hour is step one. Step two is turning that gallons-per-hour figure into a fuel budget: runtime, tank size, and cost.
Runtime
Hours = tank capacity (gallons) ÷ burn (gallons per hour). A 100 kW set at 75% load burns about 6.6 gallons per hour, so a 132-gallon day tank (500 liters) gives roughly 20 hours of running before refueling.
Tank Size for Autonomy
Multiply your burn by your autonomy hours, then add a 20% buffer for reserve and storage losses. A site burning 20 gallons per hour that must survive 48 hours needs about 960 gallons of usable fuel, and roughly 1,150 gallons of storage with the buffer built in.
Cost per Hour
Multiply gallons per hour by your fuel price per gallon. At $3.00/US gallon, a 6.6 gal/h 100 kW set costs about $20 per hour in fuel. In liters, at $0.85/L and 25 L/h, the same set costs about $21 per hour.
Cost per kWh
Divide cost per hour by the power output in kW. At $20/hour for a 100 kW set running at 75% load (75 kW actual output), the cost is about $0.27 per kWh. This is the number that lets you compare diesel against grid power or other fuels.
Every one of these figures starts with a correct conversion, which is why a dual-standard calculator is not a convenience on a fuel page. It is the load-bearing wall. When you are ready to size the generator that fits your burn rate, use the generator sizing calculator — it takes your real load and returns the kW/kVA you actually need. Our engineers confirm the fuel figure for your model and site before you order.
Let's talk
Get a Fuel-Efficient Genset Quote
Our engineers will review your fuel conversion figures, confirm your burn rate in both US and Imperial gallons, and deliver a factory-direct price — no obligation, no hidden fees. Every quote includes the generator, fuel tank, and soundproofed enclosure for a complete fuel-efficient solution.
Frequently Ask Questions
Q: How many gallons per hour is 100 liters per hour?
A: 100 liters per hour equals 26.42 US gallons per hour, or 22.00 Imperial gallons per hour. Multiply by 0.2641721 for US gallons, or by 0.2199692 for Imperial gallons.
Q: How do you convert liters per hour to gallons per hour?
A: Multiply the liters-per-hour rate by 0.2641721 to get US gallons per hour, or by 0.2199692 to get Imperial gallons per hour. For the reverse direction, multiply gallons per hour by 3.7854118 (US) or 4.54609 (UK).
Q: What is the difference between US and imperial gallons?
A: A US liquid gallon equals 3.785 liters; an Imperial (UK) gallon equals 4.546 liters. The UK gallon is about 20% larger, so a given flow produces fewer Imperial gallons per hour than US gallons per hour.
Q: How many gallons per hour does a diesel generator use?
A: Based on the fuel table above, a modern set at full load burns roughly 0.32 liters per kWh, so a 100 kW set burns about 8.5 gallons per hour (about 32 L/h). At 75% load the same set burns about 6.6 gal/h. The exact figure depends on load, engine condition, and site altitude.
Q: How do you convert liters per minute to gallons per hour?
A: Multiply liters per minute by 15.8503 to get US gallons per hour, or by 13.1982 for Imperial gallons per hour. A pump delivering 20 L/min moves about 317 US gal/h.
Q: How many liters per hour are in a gallon per hour?
A: There are 3.785 liters per hour in one US gallon per hour, and 4.546 liters per hour in one Imperial gallon per hour. The gallon you use decides the answer.
Q: Is 1 gallon the same as 4 liters?
A: Not exactly. A US gallon is 3.785 liters and an Imperial gallon is 4.546 liters. Treating a gallon as 4 liters is a rough estimate that is about 6% off for the US gallon and 12% off for the UK gallon.