How EV Cost Lab calculates estimates
EV Cost Lab is designed to help you compare scenarios more clearly, not to produce exact quotes. This page explains what the calculators include, what they do not include, and why the quality of the result depends on the assumptions you enter.
EV cost comparisons are often presented as if there were one simple answer. In practice, the result depends on mileage, charging behaviour, local energy prices, purchase price differences, ownership period, maintenance assumptions, and resale expectations. The calculators on EV Cost Lab are built to make those moving parts easier to test.
The purpose of the site is not to make sales claims. It is to give you a structured way to compare different possibilities using your own inputs, then adjust those inputs to see how sensitive the outcome is.
What the calculators are designed to do
The EV vs Gas/Petrol Calculator is designed to compare annual running costs and estimate how long it may take for lower running costs to recover an EV purchase premium. It focuses on yearly fuel or charging cost, maintenance assumptions, and a simple break-even estimate.
The Home Charger Savings Calculator focuses on one narrower question: whether shifting more charging to home could reduce annual EV charging costs enough to justify the cost of installation.
The EV Total Cost of Ownership Calculator moves beyond annual running cost and compares the larger ownership picture, including purchase price, incentives, annual running costs, maintenance, resale assumptions, and ownership period.
What is included
User-entered assumptions
The calculators use the numbers you provide, including annual distance, charging mix, fuel price, electricity rate, maintenance estimates, purchase price, installation cost, and ownership period.
Editable estimate inputs
Some tools allow you to begin with estimated local electricity rates. These are only starting points and can be edited if you know your own tariff or want to test a different case.
Scenario comparison logic
The site is built for comparison, not for fixed claims. Its strength is letting you test how the result changes when you alter key assumptions rather than treating one set of numbers as final truth.
What is not fully included
The calculators do not attempt to model every cost variable in full detail. Depending on the page, this may include financing costs, insurance differences, tax treatment, battery degradation over time, local servicing variation, installation complications, time-of-use charging behaviour, parking arrangements, or the exact structure of public charging fees.
They also do not replace a quote from an installer, a dealer, a finance provider, or a tax professional. The output is best understood as a structured estimate rather than a definitive prediction.
Why assumptions matter so much
The quality of the result depends directly on the quality of the assumptions. If fuel price is understated, if home charging is assumed to be easier than it really is, or if resale value is overly optimistic, the conclusion can become misleading. That is why EV Cost Lab is designed around editable inputs rather than fixed, one-size-fits-all defaults.
In practice, it is often more useful to run three cases than one: a likely case, a cautious case, and a more optimistic case. If the conclusion remains similar across all three, the result is more robust.
Estimated rates and local variation
Where estimated electricity rates are offered, they are intended as rough starting points rather than authoritative local tariffs. Energy pricing can vary by provider, plan type, usage pattern, and region. A broad estimate may be directionally useful, but the result will usually improve if you replace it with your own actual numbers.
The same principle applies to public charging rates. Different networks, charger speeds, and locations can produce very different real-world costs. Where possible, it is better to use a realistic average based on how you expect to charge rather than a best-case figure.
How to use the site more effectively
Start with realistic numbers
Use figures that resemble your real situation rather than numbers taken from unusually favourable examples.
Test more than one scenario
Compare a likely case with a more cautious one. This is often more informative than searching for one “correct” number.
Use the calculators together
Running cost, home charging, and total ownership are related but different questions. Using more than one calculator gives a more complete picture.
What this site is for — and what it is not for
EV Cost Lab is for structured comparison. It is for drivers and households who want to think more clearly about the cost side of EV decisions before buying, switching, or installing a charger. It is not designed to function as personalised financial advice, technical advice, or an installation quote.
The most useful way to treat the site is as a decision-support resource: a place to test assumptions, identify the variables that matter most, and narrow the range of uncertainty before making larger choices.
Use the calculators with your own numbers
If you want to test a realistic EV vs gas/petrol comparison using your own assumptions, start with the main calculator and then move to the charger or ownership tools if you need a broader view.
Open EV vs Gas/Petrol CalculatorFrequently asked questions
Are the built-in estimated rates exact?
No. They are meant as rough starting points. The calculators are more useful when you replace broad estimates with your own realistic numbers.
Why can the result change so much?
Because mileage, charging mix, local prices, purchase premium, and ownership period all matter. Small changes to key inputs can materially change the comparison.
Is EV Cost Lab giving financial advice?
No. The site is intended as an estimate and comparison resource, not as financial, tax, legal, or engineering advice.