Calculate your vehicle's fuel efficiency from distance traveled and fuel used.
Fuel efficiency = distance traveled ÷ fuel used.
Every new car in India carries an ARAI-certified mileage figure, and almost every owner discovers their real-world number falls short — typically by 15-25% in normal Indian driving conditions, and sometimes 20-40% in heavy city traffic. This isn't a manufacturer exaggeration so much as a testing-methodology gap: ARAI figures come from a controlled lab test on a chassis dynamometer, with no real traffic, minimal load, and critically, the air conditioning switched off — conditions that essentially never match how the car is actually driven day to day.
Several factors compound to create the real-world gap, and knowing them helps explain (and sometimes improve) your own number: air conditioning alone can cost 1-3 km/L depending on climate, and running AC continuously through an Indian summer can reduce mileage by 15-20% versus the AC-off ARAI figure. Stop-go city traffic involves far more idling and short acceleration bursts than ARAI's prescribed urban test cycle, both of which are fuel-hungry in ways a lab cycle doesn't fully capture. Sustained highway speeds matter too — aerodynamic drag rises with the square of speed, so consistently driving at 110 km/h instead of 80 km/h can cut mileage 8-12%, and ARAI's test never goes past 90 km/h. Vehicle load (roughly 1-2% mileage loss per extra 50kg carried) and engine condition compound over time — a car returning 15 km/L when new can drop to 12 km/L after 80,000km without proper servicing, as air filters clog, injectors get dirty and spark plugs wear.
ARAI mileage comes from controlled lab testing on a dynamometer — no traffic, minimal load, air conditioning off — conditions that essentially never match real driving. Real-world Indian driving typically returns 15-25% lower mileage than the ARAI figure, and can be 20-40% lower in heavy city traffic specifically.
Meaningfully — air conditioning typically costs 1-3 km/L depending on climate and usage, and running it continuously through a hot Indian summer can reduce mileage by roughly 15-20% compared to the AC-off ARAI test figure, which never accounts for AC load at all.
Yes — aerodynamic drag increases with the square of speed, so the fuel cost of maintaining higher speed rises faster than the speed itself. Sustained driving at 110 km/h instead of 80 km/h can cut mileage by 8-12%, and ARAI's official test cycle never even tests beyond 90 km/h, so this effect is entirely invisible in the certified figure.
Yes, and it compounds gradually enough that many owners don't notice until the gap is significant. A car returning 15 km/L when new can drop to around 12 km/L after roughly 80,000km without proper servicing, as clogged air filters, dirty fuel injectors and worn spark plugs each chip away at combustion efficiency.