A public charger can show £18.42 for a session, while your home wallbox quietly adds another cost to the electricity bill. Neither figure tells you much on its own. An ev charging cost tracker turns those scattered transactions into one useful answer: what your car actually costs to run, per mile, in your circumstances.
That means accounting for more than the headline price on a charging screen. Your electricity tariff, charging losses, parking or idle fees, subscription plans, mileage, repairs and tax treatment can all change the number. The aim is not to produce a flattering EV saving for a sales brochure. It is to keep an honest, auditable record that helps you make better decisions.
A charge total is not a cost-per-mile figure
A single charging receipt answers one limited question: what did this session cost? It does not tell you whether public charging is becoming a larger share of your driving, whether a cheap overnight tariff is offsetting expensive motorway stops, or whether your actual energy spend is rising month by month.
Cost per mile only becomes meaningful when energy cost is matched to distance driven. If you spend £120 on charging in a month and drive 1,000 miles, your energy cost is 12p per mile. But that is still only an energy figure. Add insurance, tyres, servicing, parking, finance costs or depreciation, and the ownership picture changes again.
There is no single “correct” EV cost figure for every purpose. A driver deciding where to charge may need an energy-only number. A self-employed driver preparing records needs clearly categorised expenses and receipts. Someone comparing an EV with a petrol car needs a fair comparison against their own fuel price and real-world mpg, not a generic claim about savings.
What an EV charging cost tracker needs to record
The useful tracker is the one you can keep up to date at the kerb, on the drive or one-handed in the dark. It should capture the detail behind each charge without demanding an evening of spreadsheet work.
At a minimum, each energy entry needs four distinct pieces of information:
- the date and location, such as home, workplace, public charger or marina shore power;
- the energy received or bought, measured in kWh where available;
- the amount paid, including session, parking, idle or transaction fees; and
- the odometer reading or mileage period associated with that energy use.
The source matters. Home charging is usually calculated from your electricity rate, while a public network often supplies a receipt with its own kWh total, time-based fees and taxes. Treating both as identical can hide where the money is going.
For home charging, record the rate you actually pay, including the relevant unit charge and tax. If you use a time-of-use tariff, the cost should reflect when the car charged rather than a rough household average. A 7p per kWh overnight session and a 35p per kWh evening top-up should not be blended simply because both happened at home.
Public charging requires its own discipline. Save the receipt or enter the total immediately, especially where the network charges a connection fee, an idle fee or a higher rate after a time limit. The price per kWh is useful, but the amount leaving your account is the real operating cost.
Track prepaid credit and subscriptions separately
Prepaid charging blocks can make charging look free after the payment date. It is not free. The cost has simply been paid in advance.
A proper record starts with the purchase value, then deducts each charging session from the remaining balance. This makes the burn rate visible and avoids counting the same cost twice: once when credit is bought and again when a charge is used.
Subscriptions need the same treatment. If a £10 monthly membership reduces the public charging rate, the membership is part of your charging economics. Whether it is worthwhile depends on your actual usage. A discounted rate may save money for a driver who regularly uses that network, but cost more for someone who charges there once a month.
This is where averages can mislead. A low blended cost per kWh may look excellent while hiding a subscription you no longer need. A tracker should preserve the underlying entries so you can see why the average changed.
Use mileage to create three honest views
Once charging and mileage are recorded consistently, the numbers can be separated into views that answer different questions.
Energy-only cost per mile
This is the cleanest measure of what electricity is costing you to drive. Divide the cost of charging by the miles driven over the same period. It helps compare home and public charging habits, spot an unusually expensive route and estimate the cost of a regular journey.
Be consistent about the energy point you use. Some drivers track electricity purchased at the meter or charger. Others track energy reported by the car. There will be a difference because charging and battery losses exist. Neither approach is automatically wrong, but mixing them produces a misleading result. For an expense record, purchased kWh and the amount paid are usually the most defensible basis.
Running-cost per mile
This adds the recurring costs of keeping the car on the road: servicing, tyres, insurance, repairs, inspections, cleaning, parking and similar operating expenses. It is often the figure that matters most for household budgets and self-employed work, because electricity is only one part of the monthly outgoings.
A tyre bill should not disappear because it happens once every few years. Record it when it occurs, then use a longer reporting period to avoid overreacting to one expensive month.
Total cost of ownership per mile
This is the wider view, including vehicle purchase or finance costs and depreciation where you choose to track them. It is more demanding, and it can be less useful for a quick charging decision. But it is valuable when comparing vehicles, reviewing a lease decision or understanding the real long-term cost of ownership.
The important point is to label the number properly. Calling an energy-only figure “the cost of owning an EV” is not analysis. It is a partial answer presented as a complete one.
Compare with petrol using your own baseline
An EV-versus-petrol comparison should start with your likely alternative vehicle, your current petrol price and its actual mpg. A car that returns 55 mpg and a car that returns 28 mpg create very different savings claims.
A simple comparison is enough. Calculate the petrol cost per mile from the fuel price and mpg, then compare it with your EV energy cost per mile over the same distance. If you want the fuller picture, include equivalent maintenance, insurance and ownership costs on both sides.
Be careful with conclusions after a road trip or a winter month. Public rapid charging, cold weather, towing, short trips and high motorway speeds can push the EV energy figure up. That does not make the annual record meaningless. It shows why a twelve-month view is usually more useful than one exceptional week.
Keep receipts ready for real-world reporting
For business use, the value of a tracker is not just the final total. It is the trail behind it. Store the receipt, date, supplier, tax amount where shown, mileage and business purpose alongside the expense. Categorise costs consistently, especially if a vehicle is used for both personal and work journeys.
Tax rules vary, and the right method depends on where and how you operate. A record can support your accountant or tax adviser, but it does not replace their advice. What it does provide is evidence: a clear split between charging, maintenance and other vehicle costs, rather than a card statement full of unexplained transactions.
This is particularly useful when an electricity payment covers both the household and the vehicle. Rather than claiming a guess, record the vehicle charging energy and the rate applied. The result is easier to defend and easier to revisit later.
Make the habit small enough to last
The best EV charging cost tracker is not the one with the most fields. It is the one you will use after a long journey. Log public sessions when the receipt arrives. Let home charging use a saved tariff where possible. Update the odometer regularly, and add maintenance or insurance when you pay it rather than trying to reconstruct six months of history.
Then review the record once a month. Look for the share of energy bought at home versus in public, the change in cost per mile, upcoming prepaid balance expiry and any irregular expense that needs budgeting for. You do not need to obsess over every penny. You do need enough reliable detail to see the pattern.
Amperlo is designed around that practical ledger: charges, mileage, receipts and vehicle costs in one phone-first record, producing figures you can inspect rather than marketing figures you are asked to trust.
A good record will not make a costly rapid-charge stop cheaper. It will make its effect visible, put it in context with every other mile, and give you a firmer basis for the next decision.
