Lpg Calculator
Fast, accurate and free online lpg calculator tool running directly in your browser.
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LPG profitability calculator
Check how much you can actually save by switching to autogas.
| Metrics | Gas | LPG |
|---|---|---|
| Cost 1 km | 0.53 PLN | 0.31 PLN |
| Balance sheet 1 year | - | -1 471,20 PLN |
| Balance 3 years | - | 4 586,40 PLN |
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LPG can save the budget, but only when the numbers play. This calculator does not count "by eye", but on your data: fuel consumption, fuel prices, gasoline share, annual mileage and additional costs. In a few moments you get the cost of driving 100 km, real savings, payback time of the installation and the balance after 1, 3 and 5 years.
If you've ever found yourself thinking: "LPG is cheaper, so it's definitely worth it," then don't worry - most of us start this way. The problem is that in practice nuances come into play: gas usually has higher consumption than petrol, the car still burns some PB (starting, post-injection), there are inspections of the installation and sometimes more expensive insurance. And only the sum of these elements answers the question:whether and when the installation will pay off.
#What will the LPG calculator calculate
The tool shows two worlds: "driving on gasoline only" versus "petrol + LPG". It calculates the cost of 100 km, the cost of 1 km, savings per 100/1000 km, annual, monthly and daily savings, as well as an approximate return on investment and balance over time.
Additionally, you will see the "eco" parameter, i.e. the estimated difference in CO₂ emissions - useful if you like to know how much your decisions mean in numbers, not in slogans.
#For whom does it make sense
This calculator is for you if you are considering installing LPG, you already have an installation and want to check whether it is still worth it at current prices, or you simply want to compare two cars (e.g. similar models, but different fuel consumption and mileage).
You will get the most value when you enter "real life" data: actual fuel consumption, real share of gasoline and annual kilometers - then the result is closer to the truth than the online "average".
#How to use the LPG calculator to get an honest result
Filling in the fields takes a while, but the devil is in the details. If you want to calculate the profitability of installing the installation, the most important things are: your gasoline consumption, the percentage increase in LPG fuel consumption, the share of gasoline in driving on gas and the annual mileage. Fuel prices and service costs do the rest.
#1) Gasoline consumption (l/100 km)
This is the starting point. If you're unsure, take an average over several fill-ups or from a fuel consumption tracking app. The entry "from the catalog" can be too optimistic. The more precisely you enter your PB consumption, the better the calculator will calculate the cost of 100 km and your savings.
#2) Over-combustion on LPG (%)
LPG usually requires a larger dose of fuel for the same distance. In practice, a range of around 10–20% is often assumed (depending on the engine, tuning and driving style). If you don't know, start with a value in the middle and then do a quick test: count two variants - cautious and pessimistic. The difference in the result can be surprising, especially with small runs.
#3) Petrol price and LPG price
There is no philosophy here: enter what you actually pay. If you fill up wherever you want, take the average value from the last few weeks. If you are a promotion hunter - count on your "favorite stations". It is worth remembering that the profitability of LPG increases the most when the price difference between PB and LPG is large.
#4) Share of petrol in driving on LPG (%)
This field is often omitted, but it can "eat" part of the savings. An LPG car usually starts on petrol, sometimes switches later (in winter), and in some units there is PB post-injection. If your car burns "a little gasoline despite gas", enter it here as a percentage. Thanks to this, the calculator will calculate the cost of 100 km in mixed mode, and not in the case of driving only on LPG.
#5) Annual mileage (km)
This is the heart of profitability. The more you drive, the faster the investment is likely to pay off. If you do 8-10k. km per year, the calculator is particularly useful because it will show whether the return is not getting too long. If you do 25-40k. km, it will often turn out that LPG tightens faster, but it is still worth checking the service costs and the share of gasoline.
#6) Cost of installation, service and possibly insurance
If you are just planning installation, enter the installation price (real offer, not "from"). Then add the recurring costs: annual installation service (filters, adjustments, inspection) and a possible insurance surcharge, if you have one. The calculator treats these costs as part of the annual budget, so the annual savings are closer to the true "plus" or "minus".
#How to read the results: what's important and what just looks nice
The calculator's result is not one number, but a set of clues. Some talk about current profitability (cost per 100 km and savings per 100 km), others about the investment (return in kilometers and months), and still others about the time horizon (balance after 1/3/5 years).
#Cost of 100 km: petrol vs LPG
This is the most "tangible" number. If the cost of 100 km on LPG (taking into account the share of gasoline) is significantly lower, the savings will increase with each kilometer traveled. If the difference is small, the installation may take a long time to pay for itself, and at low mileage it may not pay for itself at all.
It is also worth taking a look at the cost of 1 km. It's a simple comparison that works well when you're planning a longer commute and want to quickly assess "how much each day costs me."
#Annual savings and "real" balance
Annual savings in the calculator include fuel costs as well as additional costs (installation service and possible insurance). This is important because "saving on fuel" is not the same as "saving on your wallet".
Then the calculator calculates the balance after 1, 3 and 5 years, subtracting the cost of installing the installation. This is the moment when the spell breaks or the smile begins: you see whether after a year you are still "under the mark" or whether you are already on the upswing.
#Payback on installation (break-even) in km and months
The payback is calculated based on savings per 100 km. If the savings per 100 km are positive, the calculator calculates how many kilometers the installation cost will "make up" for the difference in driving costs. Then, using the annual mileage, it calculates the approximate number of months until the refund.
If the calculator shows no return or negative savings, it does not mean that LPG is "bad". This means that in your configuration (prices, fuel consumption, fuel injection, service costs) there is simply no advantage. Sometimes it's enough to correct one assumption to change the result, but sometimes the conclusion is simple: it doesn't stick on your runs.
#CO₂: a nice bonus that can also be calculated
The calculator also shows the estimated CO₂ savings per year. Treat this as an indicative indicator, because emissions in the real world depend on many factors, but as a comparison "petrol vs. gasoline + LPG mixture" gives a reasonable direction. If you like to make smart decisions, this is another piece of the puzzle.
#Example scenarios: how profitability changes with mileage
To make it easier to get your intuition, below are three typical driver profiles. These are not "calculator results" (because everyone has different prices and fuel consumption), but a logical comparison of what usually makes the biggest difference: annual mileage and gasoline share.
| Scenario | Annual mileage | Petrol share in LPG | What usually results from the calculations |
|---|---|---|---|
| City + short routes | 8,000–12,000 km | often higher (start-up, winter) | The turnaround can be long; the key factors are service costs and the real difference in fuel prices. |
| Mixed mode (city + highway) | 15,000–20,000 km | moderate | Often a "golden mean": the installation has a chance to pay for itself in a reasonable time, if combustion and over-combustion are reasonable. |
| Long distance / commute | 25,000–40,000 km | usually lower | Savings grow quickly and the payback time is often shorter - as long as the installation is well selected and serviced. |
#Tips to Improve Your Score Without Cheating Yourself
The best calculator in the world won't help you if the input data is "wishful". On the other hand, when you approach it honestly, you can avoid making a bad investment or confirm that it makes great sense.
- Enter the actual fuel consumption from several refuelings, not from the catalogue.
- Check two variants of LPG over-combustion (e.g. 10% and 20%) to see the range.
- Don't ignore the gasoline factor - it's a common reason for disappointment after installation.
- Include installation service per year, even if "it's just a small thing".
- Compare profitability on your mileage – 10,000. km and 30 thousand km are two different worlds.
Are you considering installation? Enter the offer from the workshop and then check after how many months you have a real return.
Do you already have LPG? Update your fuel prices and annual mileage to see if your installation still gives you an advantage.
Comparing two cars? Enter the fuel consumption and share of gasoline for both and compare the cost of 1 km and the balance over time.
#The most common mistakes in calculating the profitability of LPG
When it comes to LPG, people can argue for hours, and the problem is often trivial: everyone calculates differently. Some people look only at the price of a liter, others only at fuel consumption, and still others do not include the costs of service and gasoline. As a result, myths arise.
The most “costly” mistake is omitting the gasoline share. The second is the assumption that over-combustion is symbolic. Third - treating the cost of installation as something that will "pay for itself someday", without checking whether you will be able to make up for it in your mileage before changing your car or driving style.
#FAQ – questions that always arise
Does LPG always mean savings?
Not always. LPG is sometimes cheaper per 100 km, but the result depends on several factors at once: over-combustion, the share of gasoline, the difference in fuel prices and the costs of service and installation. If you don't drive much and your car burns a lot of fuel despite LPG, the savings may decrease or disappear. Therefore, it is worth calculating it based on your own data, instead of relying on "it works for me".
What should I enter in the "gasoline share" if I don't know how much PB I actually burn?
If you are just planning the assembly, you can adopt a conservative range and count two variants, e.g. 3-5% and 8-10%. If you already have the installation, the easiest way is to take a practical approach: watch how often you fill up with petrol and how much you drive on LPG during this time. This will allow you to roughly estimate what percentage of your riding is "attributable" to PB.
How to set LPG over-combustion so as not to cheat the result?
Instead of looking for one magic number, count the scenarios. In many cars, over-combustion around 10-20% is a reasonable starting point, but the differences between engines are large. If the outcome in both scenarios is still favorable, you have greater peace of mind. If profitability hangs in the balance, it is a sign that the decision is at the limit and it is worth clarifying the data.
Do installation service costs really matter?
Depends on your mileage, but often yes. With low annual mileage, fixed costs (service, possible additional payments) constitute a greater percentage of savings. In case of high mileage, they usually "disappear in the background", but they still influence the annual balance sheet. Adding these costs to the calculation makes the result less disappointing over time.
What does "return in kilometers" mean and should I trust it?
This is the approximate number of kilometers after which the total savings from cheaper driving will be equal to the cost of installing the installation. It is worth treating it like a compass and not an oracle, because in the real world fuel prices, driving style and mileage change. But as a reference point for a purchasing decision, it works very well: you see, we are talking about 10 thousand. km, or 80 thousand km.
Does the calculator take into account ecology and CO₂ emissions?
Yes, it shows the estimated difference in CO₂ emissions between driving on petrol and driving in mixed mode (petrol + LPG). This is an approximation, but useful for comparing two scenarios. If you want a directional picture (whether emissions are increasing or decreasing), this indicator is sufficient. If you need a "laboratory" analysis, then additional parameters come into play that are not modeled in a simple calculator.
Why does the calculator show a negative savings message?
Because in your data, driving on LPG (taking into account the share of gasoline and annual costs) is more expensive or zero compared to gasoline. Most often, the culprit is too small a difference in fuel prices, too high over-combustion, a high percentage of gasoline or high additional costs in relation to the annual mileage. This is a good time to check which assumption has the greatest impact and whether it is realistic.
#Summary that doesn't pretend to be smarter than it is
LPG can be a great move, but it is not a magic "cheaper" button. Profitability depends on your numbers: fuel consumption, gasoline share, LPG over-combustion, annual mileage and additional costs. This calculator puts it all together and shows the result in a way you can understand: how much it costs per 100 km, how much you save in a year and when the installation starts working profitably.
If you want to approach the topic calmly and without myths, fill in the fields honestly, count two scenarios (optimistic and cautious) and only then make a decision. It's still just a calculator, but a well-calculated calculator can be the best advisor when money is involved.