Need help with calculating.......

knightstyle

If I know my mpg and the cost of a litre of fuel how do I calculate the fuel cost for a 100 mile journey?
Is there a simple formulae?

BeenThroughItAll

knightstyle wrote: »

If I know my mpg and the cost of a litre of fuel how do I calculate the fuel cost for a 100 mile journey?
Is there a simple formulae?

Yep.


((100/mpg) * 4.54)*fuel cost


Done

hewhoisnotintheknow

knowing the mpg wont tell you the cost of the trip - unless you can guarentee the conditions

fill up
do the trip
fill up - this is the cost

force_ten

hewhoisnotintheknow wrote: »

knowing the mpg wont tell you the cost of the trip - unless you can guarentee the conditions

fill up
do the trip
fill up - this is the cost

but by doing this the 100 mile trip will cost you more, my car will do 700 miles on a full tank and if i am doing a 100 mile trip with full tanks then i am carrying 13 gallons of fuel that i do not need, so extra weight will make the car less fuel efficient

money saving expert says never run with full tanks when you dont need to

Nodding_Donkey

Sorry but that is rubbish. Going to the garage and part filling the car is a false economy, what about the fuel, and time, you use filling up. Just brim it, drive until empty and brim it again.

force_ten

Nodding_Donkey wrote: »

Sorry but that is rubbish. Going to the garage and part filling the car is a false economy, what about the fuel, and time, you use filling up. Just brim it, drive until empty and brim it again.

it is not rubbish it costs about £96.00 to brim the tank so why would i have near £100.00 worth of fuel sitting in my tank just to save a 200 yard trip to the gas station

I do not use my car as a daily driver so when i go somewhere i put in enough fuel to get me there and back with a little extra as a buffer zone

knightstyle

Well this is not for a specific 100 mile trip I just wanted to see how much a car with lower mpg would actually cost me.
I have just switched from an Auris 1.4 diesel auto 50mpg to a Juke 1.6 petrol which seems to give 36mpg but as it is under a year old and new to me this mpg may not be exact.

AdrianC

force_ten wrote: »

but by doing this the 100 mile trip will cost you more, my car will do 700 miles on a full tank and if i am doing a 100 mile trip with full tanks then i am carrying 13 gallons of fuel that i do not need, so extra weight will make the car less fuel efficient

Your car weighs a ton and a half or so - 1,500kg. A full tank of fuel weighs about 50kg.

Seriously, how much do you think that a weight difference of one third of one percent is going to make?

To figure the calculation, you only need to one know piece of information. There are 4.5 litres in a gallon. The rest is basic numeracy.

One gallon - 4.5 litres - takes you 36 miles. So how many 36 mile gallons do you need for 100 miles? Divide 100 by 36.

But we buy fuel per litre. So multiply the price by 4.5 to see how much one gallon costs you. Then multiply that by the number of gallons you need.

Your average primary school kid should be able to figure it.

force_ten

AdrianC wrote: »

Your car weighs a ton and a half or so - 1,500kg. A full tank of fuel weighs about 50kg.

Seriously, how much do you think that a weight difference of one third of one percent is going to make?

carrying an extra 50kg of Weight will increase your fuel consumption by about 2%

AdrianC

force_ten wrote: »

carrying an extra 50kg of Weight will increase your fuel consumption by about 2%

Please show your working.

force_ten

knightstyle wrote: »

Well this is not for a specific 100 mile trip I just wanted to see how much a car with lower mpg would actually cost me.
I have just switched from an Auris 1.4 diesel auto 50mpg to a Juke 1.6 petrol which seems to give 36mpg but as it is under a year old and new to me this mpg may not be exact.

around here a gallon of petrol will cost you £6.10 p so 100 miles will cost £16.95 at 36 mpg

around here a gallon of diesel will cost you £6.30 p so 100 miles will cost you £12.60 at 50 mpg

so your new car costs you an extra £4.35 p in fuel cost to cover 100 miles based on the gas prices around here today