Renewables
EV Charging Cost & Time Calculator
Work out charge time and cost from empty to target
Updated 12 July 2026 · Live
What this tool does
Works out how long an EV takes to charge and what it costs from the current charge level to a target, at a given charger power and electricity price.
Enter the battery size, current and target charge, charger power and electricity price; the calculator returns the charge time and cost.
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Formula Used
How the ev charging cost & time works
The energy needed is the battery capacity times the gap between current and target charge. Charge time is that energy divided by the charger power, and cost is the energy times your electricity price. Because it assumes the charger runs at full power throughout, the time is a best case — real charging slows as the battery fills.
What you enter
Enter the battery size, current and target charge, charger power and electricity price; the calculator returns the charge time and cost. Every field is editable, and the result recalculates the moment you change a value.
Reading the result
The time and cost are a clean best case at steady power. Above roughly 80% charge, and in cold weather, real charging tapers and some energy is lost to heat, so treat the figures as a floor.
Safe by design
This calculator does the arithmetic of sizing — quantities, geometry and cost. It deliberately stops at the line a certified installer must sign off. It will never tell you a cable or fuse size, an earthing arrangement, a battery charge voltage, or a roof structural load: those are regulated calculations where a wrong number causes fire, electrocution or collapse. All electrical work must be carried out by a qualified, certified installer, and this page is not an installation guide.
Assumptions and limits
Real charging is not linear: rates taper above about 80%, cold batteries charge more slowly, and a few percent is lost as heat. Electricity prices vary by time and tariff and are entered by you. This pairs naturally with EV running-cost tools if you are comparing motoring costs.
Using it with the rest of BuildMetricLab
This calculator is one step in planning a system. Pair it with the other solar sizing, geometry and cost tools to go from an energy figure to a panel count, a layout and a costed bill of materials. Every BuildMetricLab tool runs entirely in your browser — no sign-up, nothing sent to a server, and the formula is shown on the page so the maths can be audited.
Sources & methodology
Works out how long an EV takes to charge and what it costs from the current charge level to a target, at a given charger power and electricity price. Every result is calculated from the values you enter, all inputs are editable, and no time-sensitive prices or tariffs are embedded.
Frequently asked questions
Why is real charging slower than this?
Charging tapers as the battery fills, especially above about 80%, and slows in cold weather. This tool assumes steady full power, so the time it gives is a best case.
How much does a full charge cost?
Multiply the energy added by your electricity price. Set current to 0% and target to 100% to see a full-charge cost at your tariff.
What charger power should I enter?
Home chargers are typically 3–7 kW, workplace units 7–22 kW, and public rapids 50–350 kW. Use the lower of the charger and the car’s onboard limit.
Why enter my own electricity price?
Prices vary by tariff and time of day and change often. Entering your own — including a cheap overnight rate if you have one — keeps the cost accurate.
Spotted something off?
Calculations or display — let us know.