EV Charging Time Calculator Widget
Tell EV drivers how long a charge will take before they plug in. Choose a charger from a 2.3 kW household socket to a 350 kW DC fast charger, set the battery size, start and target levels, charging efficiency and the car's own AC and DC limits, and get the time, the power actually used and the energy added.
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<iframe src="https://a2z.tools/embed/w/ev-charging-time-calculator" title="EV Charging Time Calculator by A2Z Tools" width="100%" height="700" style="border:0;width:100%" loading="lazy" allow="clipboard-write"></iframe>
A plain iframe. Works everywhere, including site builders that strip scripts. Adjust height if your content needs more room.
<div data-a2z-widget="ev-charging-time-calculator" data-height="700"></div> <script async src="https://a2z.tools/embed.js"></script>
Adds a small script (what it does) that sizes the widget to fit its content, loads it lazily and keeps it isolated from your page's CSS.
Works with
How it works
The power that flows is the lower of the charger's rating and what the car accepts: an 11 kW wallbox cannot push more than a car with a 7.4 kW on-board charger will take, and a 350 kW DC unit is capped at the car's maximum DC rate. Presets up to 22 kW are AC, 50 kW and above are DC, and a custom power follows the same split. Energy needed is the usable battery capacity times the change in charge level; dividing by power times charging efficiency gives the time. AC charging is treated as constant power. DC fast charging is not: cars cut power as the battery fills, so above 80% the widget assumes power falls in a straight line to a tenth of its starting value at 100%. That makes the last 20% take about 2.6 times as long as at full power, and the widget shows the no-slowdown time alongside. A 75 kWh battery from 20% to 80% on 11 kW at 90% efficiency takes 4 h 33 min.
Calculation method
- Power used = min(charger kW, car's maximum AC or DC kW)
- Energy into the battery = usable kWh x (target % - start %) / 100
- Time (constant power) = energy / (power x efficiency)
- DC above 80%: p(s) = P x (1 - 4.5 x (s - 0.8)), so p(100%) = 0.1 P
- Time from s1 to s2 above 80% = battery / (P x efficiency) x ln(p(s1) / p(s2)) / 4.5
Worked examples
Home wallbox top-up
Inputs: 75 kWh usable; 20% to 80%; 11 kW AC; car accepts 11 kW AC; 90% efficiency
Result: 4 h 33 min; 45 kWh added (50 kWh drawn)
45 kWh / (11 kW x 0.9) = 4.55 h.
Motorway fast charge
Inputs: 75 kWh; 10% to 80% on 150 kW DC; car accepts 150 kW; 90% efficiency
Result: About 23 min for 52.5 kWh
Charging on to 100% would take about 40 min in total because of the taper, against 30 min at constant power.
Limitations
- Real charging curves vary by car, battery temperature and state of health; the DC taper is a generic estimate.
- Shared charger cabinets, grid limits and cable faults can deliver less than the rated power.
- Treats efficiency as constant across the session.
Where publishers use it
- A home charger installer's page comparing 7.4 kW and 22 kW wallboxes
- An EV review site's ownership guide
- A charging network's page explaining why the last 20% is slow
- A fleet operator's planning page for overnight depot charging
- A road-trip blog working out stops on a long drive
Questions
Why does my car charge at 7 kW on a 22 kW charger?
AC charging speed is set by the car's on-board charger. Many cars accept 7.4 or 11 kW on AC, so a 22 kW post delivers only that. Enter your car's maximum AC rate and the widget applies the same limit.
Why is DC fast charging slower near full?
To protect the cells, the battery management system reduces current as the cells approach full voltage. The exact curve depends on the car and the battery temperature; this widget uses a simple straight-line taper above 80%, so treat the time above 80% as an estimate.
What charging efficiency should I use?
Compare the kWh your charger or meter reports for a session with the kWh the car says it added; the ratio is your efficiency. Without a measurement, 85-90% is a reasonable planning value for AC and a little higher for DC, where conversion happens in the charger.
Which battery capacity should I enter?
The usable capacity, not the gross figure. A car sold as 77 kWh may have about 74 kWh usable. The manufacturer's specification or owner forums usually list both.
How fast is each charger level?
In the US, Level 1 uses a 120 V outlet, Level 2 a 240 V or 208 V supply, and DC fast chargers deliver up to several hundred kW. The presets here use common European AC ratings (2.3 to 22 kW) and DC ratings of 50, 150 and 350 kW.
Does cold weather change the result?
Yes. A cold battery accepts much less DC power until it warms up, and cabin heating draws power during a slow AC charge. Preconditioning the battery before a fast-charge stop helps.
Sources
- Electric Vehicle Charging Stations - U.S. Department of Energy, Alternative Fuels Data Center . Describes Level 1 (120 V), Level 2 (240/208 V) and DC fast charging at power outputs up to 500 kW, and notes charging time depends on the charger, battery and other factors. Checked 2026-10-01.
Cite or recommend this tool
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A2Z Tools EV Charging Time Calculator https://a2z.tools/embed/ev-charging-time-calculator
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[A2Z Tools EV Charging Time Calculator](https://a2z.tools/embed/ev-charging-time-calculator)
EV Charging Time Calculator by A2Z Tools - https://a2z.tools/embed/ev-charging-time-calculator
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