Battery kWh + charge % + tariff → cost per charge, per 100km/mile, and how much you save vs petrol — browser-only
- Runs locally
- Category Calculator
- Best for Getting a realistic range before a purchase, plan, workout, or schedule decision.
Enter your usable battery size, the charge window, your tariff and a charging-loss percentage. You get the energy actually pulled from the grid, the cost of one charge, and — with your real consumption — the cost per 100 km/mile and how it compares to a petrol car.
AC home charging ≈ 8–12%, DC fast charging ≈ 3–6%.
Leave blank to skip the petrol comparison.
What this tool does
Work out exactly what it costs to charge your electric car. Enter your usable battery size in kWh, the start and target state of charge (or just tick "full charge"), your electricity tariff per kWh, and a charging-loss percentage (the energy that disappears as heat between the wall and the battery — typically 8–12% on AC home charging, less on DC fast charging). The tool returns the kWh actually pulled from the grid, the cost of that single charge, and — once you give it your real-world consumption in kWh/100km — the cost to drive 100 km or 100 miles. Toggle between a home tariff and a public fast-charge rate to see the gap, because rapid charging often costs two to four times your home rate. Add an optional petrol comparison (your fuel economy plus pump price) and the calculator shows the side-by-side per-100km cost and the money you keep every time you plug in instead of fill up. Everything is computed in your browser, the inputs ride along in the URL so you can share a worked example, and your tariff and unit preferences are remembered locally between visits. No accounts, no uploads, no tracking of what you drive.
Tool details
- Input
- Numbers
- The page exposes text boxes, numeric controls, file pickers, or structured inputs depending on the tool.
- Output
- Live result + Copy
- The result area focuses on usable output, with copy, download, or preview actions when supported.
- Privacy
- Browser-side processing
- The main tool logic does not call an external API, so inputs normally stay in the current tab.
- Save / share
- Shareable URL state
- Key settings are encoded in the URL so another person can reopen the same setup.
- Performance budget
- Initial JS <= 11 KB
- No WASM budget is declared, keeping the tool quick to open on mobile.
- Best fit
- Calculator · Operations
- Category and role tags drive related tools, internal links, and quick fit checks.
How to use
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1. Input
Paste or drop your content into the tool panel.
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2. Process
Click the button. All processing is local in your browser.
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3. Copy / Download
Copy the result or download to disk in one click.
How EV Charging Cost Calculator fits into your work
Use it for fast estimates, comparisons, and planning numbers before you make the final call.
Calculation jobs
- Getting a realistic range before a purchase, plan, workout, or schedule decision.
- Comparing scenarios by changing one input at a time.
- Turning rough assumptions into a number you can discuss.
Calculation checks
- Double-check units, dates, rates, and rounding assumptions.
- Treat health, finance, tax, and legal outputs as planning aids, not professional advice.
- Save the inputs that produced an important result so you can reproduce it later.
Good next steps
These links move the current task into a more complete workflow.
- 1 Fuel Cost Calculator Trip fuel cost from distance + economy + price — round trip, per-person split, L/100km ⇄ MPG — browser-only. Open
- 2 Electricity Cost Calculator Power × hours × tariff → kWh and cost per day, month, and year — add multiple appliances, account for standby — browser-only. Open
- 3 Unit Converter Convert between length, weight, temperature, area, volume, speed, time — instant, browser-only Open
Real-world use cases
Price an overnight home charge from 20% to 80%
You plug in with the battery at 20% and want it at 80% by morning. Enter your usable battery size (say 64 kWh), set start 20% and target 80%, add a 10% AC charging loss, and type your home tariff. The tool shows the 60% window is 38.4 kWh into the battery, about 42.7 kWh from the wall after loss, and the exact cost on your rate. That is the number to compare against an off-peak tariff: shifting this same charge to a cheap overnight window is usually the single biggest lever on your EV running cost.
See the real penalty of a motorway rapid charge
Mid-road-trip, you stop for a 30–80% top-up on a DC charger. Flip the tariff toggle to the fast-charge rate, set start 30% and target 80%, and drop the loss to 5% (DC charging is more efficient at the car). The cost jumps versus your home number — often two to three times — and now you can decide whether to grab a smaller, cheaper top-up to reach the next stop or pay for the full convenience charge. Seeing the dollar gap makes the road-trip math obvious.
Settle the EV-vs-petrol argument with your own numbers
Someone insists their petrol car is "basically the same cost" to run. Enter your EV at its real winter consumption (say 20 kWh/100km) on your home tariff, then add the petrol car's 8 L/100km and the current pump price. The side-by-side per-100km cost ends the debate with a number rather than a vibe — and if you want the unit consistent, the fuel-cost-calculator and unit-converter handle MPG, km/L and gallon conversions.
Budget the monthly charging cost of a new lease
Before signing an EV lease, you want the all-in monthly cost, not just the payment. Take your expected monthly mileage, divide by 100, multiply by the per-100km charging cost this tool gives you on your home tariff, and you have the energy line of your budget. Pair it with the car-lease-calculator for the depreciation and rent side, and you have an honest total-cost-of-ownership figure to compare against keeping your current car.
Convert a foreign EV review's running cost to your currency
A European reviewer quotes "€9 per 100 km" but you charge in dollars on a different tariff. Re-enter the consumption they used with your own per-kWh rate to get a like-for-like number, and if you need to sanity-check their tariff against yours, the currency-converter turns their €/kWh into your local currency first. Now the review's running-cost claim means something for your driveway, not theirs.
Common pitfalls
Using the on-dash "energy used" figure as the cost basis. The car reports energy that went into the battery; your meter bills you for energy that came out of the wall, which is higher by the charging loss. Always add the loss (8–12% AC, 3–6% DC) so the cost matches your utility bill, not the optimistic in-car readout.
Mixing up battery capacity with usable capacity. A "75 kWh" pack often has only ~70 kWh usable because the BMS reserves a buffer top and bottom. Charging from 0–100% on the usable figure is the right input; using the gross nameplate number overstates both the energy and the cost.
Comparing a home-charge EV cost to a full-tank petrol cost without normalising distance. The only fair comparison is per 100 km (or per 100 miles) — divide each by the same distance. Comparing "$8 to charge" against "$60 to fill up" is meaningless until you know how far each takes you.
Privacy
All math — battery energy, charging-loss gross-up, per-100km cost, and the petrol comparison — runs as plain JavaScript in your browser tab. Your battery size, tariff, mileage and consumption never touch a server, and there is no analytics on what you charge or drive. The one caveat: the shareable URL encodes your current inputs in the query string so a "share this estimate" link reproduces the calculation, which means anything you share lands in the destination server's access log. For a one-off worked example that is fine; if your tariff or mileage is something you treat as private, copy the result text instead of sharing the URL.
FAQ
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