LPG Conversion Payback Calculator
The LPG conversion payback calculator helps you assess whether installing a liquefied petroleum gas (LPG) system on your car is financially worthwhile. Compare petrol and LPG running costs, calculate savings per 100 km, and estimate how long it will take to recover the installation investment.
How to use
- Enter the current price per liter of petrol.
- Enter the current price per liter of LPG.
- Specify the average petrol consumption in liters per 100 km.
- Enter the expected LPG consumption after conversion.
- Input the total LPG installation cost, including equipment and labour.
- Enter your average monthly or annual mileage.
- Review the result: fuel costs, expected savings, and payback period.
What Is LPG Payback
An LPG (liquefied petroleum gas) system allows a car to run on gas instead of — or alongside — petrol. The main economic benefit is a potentially lower cost per kilometer driven.
However, LPG conversion requires an upfront investment, which may include injectors, a reducer, an electronic control unit, a gas cylinder, pipes, installation, and system tuning. Payback occurs when accumulated fuel savings offset the initial conversion cost.
- Petrol and LPG prices
- Fuel consumption before and after LPG conversion
- Vehicle mileage and installation cost
- LPG system maintenance costs
- Petrol used during engine startup or specific modes
- Potential future changes in fuel prices
LPG Payback Calculation Formula
- Petrol cost (100 km) = Petrol consumption × Petrol price
- LPG cost (100 km) = LPG consumption × LPG price
- Savings per 100 km = Petrol cost − LPG cost
- Savings per km = Savings per 100 km ÷ 100
- Break-even mileage = Installation cost ÷ Savings per km
- Payback period (months) = Break-even mileage ÷ Average monthly mileage
LPG Payback Calculation Example
A sample calculation for a car used for daily commuting: petrol price — UAH 60/L, LPG price — UAH 35/L, petrol consumption — 8 L/100 km, LPG consumption — 9.2 L/100 km, installation cost — UAH 30,000, average monthly mileage — 1,500 km.
- Petrol cost: 8 × 60 = UAH 480 / 100 km
- LPG cost: 9.2 × 35 = UAH 322 / 100 km
- Savings: 480 − 322 = UAH 158 / 100 km
- Savings per km: UAH 1.58
- Break-even mileage: 30,000 ÷ 1.58 ≈ 18,987 km
- Payback period: ~12.7 months (≈13 months)
How Annual Mileage Affects LPG Payback
Annual mileage is one of the key factors in the economic viability of LPG conversion. At low mileage, fuel savings accumulate slowly; with heavy use, the initial costs can be recovered much faster.
When evaluating LPG conversion, consider not only your current mileage but also your plans for the vehicle. If you plan to sell the car soon, full payback may not occur.
Additional Costs to Consider
- Periodic LPG system maintenance
- Filter and consumable component replacement
- System diagnostics and tuning
- Petrol used during startup or specific driving modes
- LPG system repairs
- Other costs specific to your vehicle and conversion procedure
When LPG Conversion May Be Worthwhile
LPG conversion can make economic sense when the vehicle has significant annual mileage, the savings per kilometer are sufficient, and the owner plans to keep the car for a long time.
- Compare scenarios: low, medium, and high annual mileage
- Test different petrol and LPG price combinations
- Check actual LPG consumption figures for your specific vehicle
- Consider different installation cost options
- Factor in expected maintenance costs over the ownership period
Frequently Asked Questions
How long does it take for LPG to pay back?
The payback period depends on the installation cost, the difference in petrol and gas running costs, actual fuel consumption, and mileage. Results can vary significantly between different vehicles.
Is LPG worth it at low mileage?
At low annual mileage, savings accumulate more slowly. If the car is used infrequently or you plan to sell it soon, the initial investment may not pay back within a reasonable timeframe.
Why does a car use more gas than petrol in liters?
LPG consumption in liters per 100 km is often higher than petrol consumption due to differences in fuel properties and engine behavior. The actual difference depends on the car, system settings, and driving conditions.
Should I account for petrol use after LPG conversion?
Yes. Petrol may still be used during engine startup or in certain operating modes. If the calculator doesn't account for this, the result may overestimate the savings.
Does the calculator include LPG maintenance costs?
It depends on the specific tool. If only the installation price and fuel costs are included, maintenance costs should be added separately for a more accurate estimate.
How does payback change if fuel prices rise?
It depends on how petrol and LPG prices change relative to each other. If the per-kilometer cost difference increases, payback may accelerate; if it narrows, payback may slow down.
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