If you want to switch between mpg and gph, you need to know the speed in mph.
As a rule of thumb, you can convert gph to mpg by dividing the speed (mph) by the fuel consumption (gph). If you want to convert mpg to gph, you have to divide the speed (mph) by the fuel consumption (mpg).
If you want to find out more about these conversions and check out some examples, keep reading.
We at PowerSportsGuide have compiled all you need to know under one roof!
(Note that the listed formulas work in cases of average speed and average fuel economy figures.)
How do You Convert Mpg to Gph?
If you know the speed, you can convert mpg to gph by dividing the speed (mph) by the fuel consumption (mpg).
In other words, the mpg to gph formula is as follows:
MPH (miles per hour) / MPG (miles per gallon) = GPH (gallons per hour)
Example:
Traveling at 50 miles per hour while getting 5 miles per gallon = 10 gallons per hour
50 mph / 5 mpg = 10 gph
How do You Convert Gph to Mpg?
If you know your speed, you can convert gph to mpg by dividing the speed (mph) by the fuel consumption (gph).
In other words, the gph to mpg formula is as follows:
MPH (miles per hour) / GPH (gallons per hour) = MPG (miles per gallon)
Example:
Traveling at 50 miles per hour while using 10 gallons per hour = 5 miles per gallon
50 mph / 10 gph = 5 mpg
Conclusion
If you want to convert mpg to gph and vice versa, you need to know your speed in mph.
Contrary to popular belief, you can’t switch between these figures without knowing the speed of your vehicle or vessel!
Once you know your average speed, the conversion formulas are as follows:
MPH / MPG = GPH
MPH / GPH = MPG
If you want to monitor the fuel economy of a boat, the best practice is to hook a GPS device to a digital gauge (if available).
Modern digital gauges are designed to display the average, instant, and trip average fuel economy even in mpg, as long as they are paired with a GPS unit.
