Car & Vehicle

Fuel Savings Calculator

What better mileage is worth in rupees over a year, and how long a change takes to pay for itself.

9 inputs Free, no sign-up

Your figures

How far you actually drive in a year. The odometer over twelve months is the best source.

What you measure today.

What you expect to get. This is your estimate - nothing on this page predicts it.

The cost of the tyres, the service, the conversion or whatever you are changing. Leave blank if it costs nothing.

Try an example

Result

Your result

Enter your figures and the result appears here.

Estimates only. Rates, fees and specifications change. Confirm against the official source before you rely on a figure — see our disclaimer.

About this calculator

A mileage improvement is worth whatever it saves over the distance you actually drive. One kilometre per litre sounds small; over 15,000 km a year with petrol at ₹105 it is several thousand rupees.

Enter what you get now and what you expect to get afterwards. If the change costs something up front, this page also says how far you have to drive before the saving covers it.

How to use this calculator

  1. Enter the distance you cover in a year.
  2. Enter your current mileage and the fuel price you pay.
  3. Enter the mileage you expect afterwards. Use a figure you have reason to believe — something you have measured before, or a change you have seen on another vehicle.
  4. If the change costs money up front, enter that too.

The formula

Cost per km   = Price per litre / Mileage      (for each case)
Yearly cost   = Cost per km x Distance
Saving        = Cost now - Cost after
Break-even km = Up-front cost / (Cost per km now - Cost per km after)

The break-even figure is the honest one. A change that saves ₹4,000 a year and costs ₹40,000 takes ten years to pay back, which is longer than most people keep making the same journeys.

SymbolMeaningUnit
Distance Distance driven in a year km or mi
Mileage now What you measure today km/L or mpg
Mileage after What you expect afterwards km/L or mpg

Worked example

15,000 km a year, petrol at ₹105, going from 14 to 16 km/L:

Now    = 105 / 14 = 7.50 per km  -> 112,500 a year
After  = 105 / 16 = 6.5625 per km ->  98,437.50 a year
Saving = 14,062.50 a year

If the change cost ₹30,000, it pays for itself in a little over two years of that driving.

Notes and limits

  • The improved figure is your estimate. This page costs it; it does not endorse it. Claims about fuel-saving devices in particular are worth treating with suspicion until you have measured a tank yourself.
  • Things that genuinely move mileage: correct tyre pressure, removing a roof box, a serviced engine, less aggressive driving and less weight. Most of these cost little or nothing.
  • Measure before and after with the same method and over the same kind of driving. A change made in December and measured in April has the weather in it.
  • A percentage improvement is worth more on a thirsty vehicle than a frugal one, because the same percentage of a larger bill is a larger number.

What this calculation assumes

  • The improved mileage is a figure you supplied. It is not a prediction made by this page.
  • Fuel prices are taken as constant over the period.
  • Only fuel is compared. Any change in servicing or tyre cost is not included.

Frequently asked questions

How much does one extra km/L save?

It depends on where you start. Going from 10 to 11 km/L over 15,000 km at ₹105 saves about ₹14,300 a year; going from 20 to 21 saves about ₹3,750. The same one-unit step is worth far more at the thirsty end.

Do fuel-saving devices work?

This page has no opinion to sell you and no figure to offer. Enter whatever improvement is being claimed and see what it would be worth; then measure three tanks before and three after, and compare. Most claims do not survive that test.

What is a break-even distance?

The distance you have to drive before the money saved on fuel equals what the change cost up front. Below it you are out of pocket; above it you are ahead.

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