Fuel Cost Calculator
Calculate Trip Fuel Cost, Litres Needed & Cost Per KM — Free & Instant
What is a Fuel Cost Calculator?
A fuel cost calculator is a tool that tells you exactly how much money you will spend on petrol, diesel, or CNG for any trip — whether it is your daily office commute, a weekend road trip, or a long cross-country drive. Instead of guessing at the petrol pump, you enter your trip distance, current fuel price, and your vehicle's fuel efficiency to get an instant, accurate cost breakdown. Our calculator also handles round trips, toll charges, and splits the cost per passenger — making it the most complete free fuel cost tool available online.
How to Calculate Fuel Cost for a Trip
Calculating your trip fuel cost involves three pieces of information: the distance you will travel, the price of fuel per litre (or gallon), and your vehicle's fuel efficiency. Once you have those, the formula is straightforward:
Fuel Needed (litres) = Distance (km) × Consumption (L/100km) ÷ 100 Fuel Cost = Fuel Needed × Price per Litre Total Trip Cost = Fuel Cost + Toll Charges
For example, if you are driving 300 km in a car that uses 7 litres per 100 km and fuel costs ₹100 per litre:
Fuel Needed = 300 × 7 ÷ 100 = 21 litres Fuel Cost = 21 × 100 = ₹2,100 Round Trip Cost = ₹2,100 × 2 = ₹4,200
Fuel Cost Formula for MPG (Miles Per Gallon)
If your vehicle measures efficiency in miles per gallon — common in the US and UK — the formula adjusts slightly:
Gallons Needed = Distance (miles) ÷ MPG Fuel Cost = Gallons Needed × Price per Gallon
Example: A 400-mile road trip in a car that gets 32 MPG at $3.50 per gallon: 400 ÷ 32 = 12.5 gallons × $3.50 = $43.75 total fuel cost. Cost per mile = $0.11.
How to Calculate Fuel Cost Per KM
Cost per kilometre is one of the most useful numbers for comparing vehicles or planning a daily commute budget. Use this formula:
Cost Per KM = (Fuel Price per Litre × Consumption L/100km) ÷ 100
Example: Fuel at ₹105/litre with a car consuming 8 L/100km gives a cost of (105 × 8) ÷ 100 = ₹8.40 per kilometre. Our calculator shows this figure automatically for every trip you calculate.
How to Calculate Monthly Fuel Cost for Daily Commute
To find your monthly petrol or diesel expense for commuting, multiply your daily round-trip distance by your working days per month, then run it through the fuel cost formula. For example, if your office is 25 km away and you work 22 days a month, your monthly commute distance is 25 × 2 × 22 = 1,100 km. At 8 L/100km and ₹105/litre, that is 88 litres × ₹105 = ₹9,240 per month in fuel alone. This is exactly the kind of calculation this tool is built for.
Understanding Fuel Efficiency — L/100km vs km/L vs MPG
Fuel efficiency is expressed in different units depending on the country and vehicle type. Our calculator supports all three formats:
- L/100km (litres per 100 kilometres) — used in Europe, Australia, India, Pakistan, and most of Asia. A lower number means better efficiency. A typical car uses 6–10 L/100km.
- km/L (kilometres per litre) — commonly used in India and South Asia, especially for bikes and smaller cars. A higher number means better efficiency. Bikes typically achieve 40–70 km/L; cars get 10–20 km/L.
- MPG (miles per gallon) — standard in the USA and UK. A higher number means better efficiency. Most US cars achieve 25–40 MPG; trucks and SUVs typically get 15–25 MPG.
Typical Fuel Efficiency by Vehicle Type
Not sure what efficiency to enter? Use these real-world averages as a starting point, then check your vehicle's actual consumption from your owner's manual or fuel-up history:
- Motorcycle / Bike: 30–70 km/L (3–3.5 L/100km)
- Small Hatchback (Petrol): 14–20 km/L (5–7 L/100km)
- Sedan / Mid-size Car: 10–16 km/L (6–10 L/100km)
- SUV / Crossover: 8–13 km/L (8–12 L/100km)
- Diesel Car: 14–22 km/L (4.5–7 L/100km)
- CNG Vehicle: typically 20–30 km/kg equivalent
- Pickup Truck / Large SUV: 6–10 km/L (10–16 L/100km)
- Hybrid Car: 18–28 km/L (3.5–5.5 L/100km)
How to Reduce Your Fuel Cost on Every Trip
Fuel is one of the biggest ongoing expenses for most drivers. The good news is that small changes in driving habits and vehicle maintenance can reduce fuel consumption by 10% to 25% without any major investment:
- Drive at a steady speed — fuel consumption increases sharply above 90–100 km/h. Every 10 km/h over 100 adds roughly 8–10% to your fuel bill.
- Keep tyres properly inflated — underinflated tyres increase rolling resistance and can cost you 3–5% in extra fuel per trip.
- Avoid aggressive acceleration and hard braking — smooth driving can improve fuel efficiency by up to 15% in city traffic.
- Remove unnecessary weight — carrying an extra 50 kg reduces fuel efficiency by roughly 1–2%.
- Use air conditioning wisely — AC increases fuel consumption by 5–15% depending on the vehicle and outside temperature.
- Service your vehicle regularly — a dirty air filter or old spark plugs can reduce mileage by up to 10%.
- Carpool and split costs — use the passenger split feature above to see exactly how much everyone saves by sharing a ride.
Petrol vs Diesel vs CNG — Which is Cheaper Per KM?
The cheapest fuel per kilometre depends on your vehicle's efficiency with each fuel type and the current price at the pump. As a general guide for Indian drivers in 2025: CNG offers the lowest cost per km (often 40–60% cheaper than petrol) but requires a CNG-compatible vehicle. Diesel is typically 20–30% cheaper per km than petrol for high-mileage drivers due to better efficiency, but the price gap has narrowed in recent years. Petrol vehicles have lower upfront costs and are more widely available. Use our calculator to compare your exact costs by switching the fuel type and adjusting the price and efficiency for each option.
Road Trip Fuel Budgeting Tips
- Always calculate both one-way and return trip costs before you leave
- Add 10–15% buffer to your estimate for unexpected detours and traffic
- Check fuel prices at different stops along your route — prices vary by city
- Fill up before entering expressways where fuel stations may have premium pricing
- Highway driving is typically 15–20% more fuel-efficient than city driving
- Split tolls and fuel costs evenly using the per-passenger calculation above