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Calculation Machine

EV Charging Time Calculator

Hours to charge from any state of charge, at any power.

Reviewed by the Calculation Machine team · Updated 24 October 2026 · How we check our maths

Your values

ⓘ Live results

Results
Charging time
4 h 33 min
Energy added
45 kWh
Grid energy drawn
50 kWh
Range gained
158 mi
Average rate
35 mi of range per hour

Quick answer

EV charging time is the energy you need divided by the charger's power, adjusted for losses: hours = battery kWh × (target % − start %) ÷ (charger kW × efficiency). Charging a 75 kWh battery from 20% to 80% adds 45 kWh; on an 11 kW charger at 90% efficiency that takes 45 ÷ 9.9 ≈ 4 hours 33 minutes.

What the EV Charging Time calculator does

This calculator estimates how long it takes to charge an electric vehicle from any starting state of charge to any target, at any charger power. It also shows the energy added to the battery, the energy drawn from the grid, the range you gain and the average miles of range added per hour of charging.

Charging speed is limited by the lower of two numbers: what the charger can supply and what the car can accept. On AC (Level 1 and Level 2) the car's onboard charger sets the cap – a car with a 7.2 kW onboard charger will not charge faster on an 11 kW wallbox. On DC fast chargers, the car's maximum DC rate and its charging curve set the limit.

The result assumes constant power from start to finish. That is close to reality for home AC charging, but DC fast charging slows down sharply above roughly 80%, so treat fast-charge times as a best case. For the cost of the same session, use the EV charging cost calculator.

The formula

Energy added (kWh) = capacity × (target % − start %) ÷ 100 Grid energy (kWh) = energy added ÷ (efficiency ÷ 100) Hours = grid energy ÷ charger kW Range gained = energy added × mi/kWh

Formula variables
SymbolMeaningUnit
capacityUsable battery capacitykWh
start %, target %State of charge before and after charging%
charger kWPower delivered – the lower of the charger rating and the car's maximum acceptance ratekW
efficiencyShare of grid energy that reaches the battery, typically 85–95%%
mi/kWhVehicle efficiency, used for range gainedmiles per kWh

This is an energy balance, the method used in US Department of Energy charging guidance. AC charging power = volts × amps ÷ 1,000: a 240 V circuit delivering 32 A gives 7.7 kW. Cold batteries, battery preconditioning, other loads on a shared circuit and the DC taper all make real sessions longer than this estimate.

Worked examples

Level 1 from a standard outlet

A 60 kWh EV plugged into a 120 V household outlet (about 1.4 kW) from 10% to 100%, at 85% efficiency, getting 4 mi/kWh.

Inputs

  • Battery capacity60 kWh
  • Starting charge10 %
  • Target charge100 %
  • Charger power1.4 kW
  • Charging efficiency85 %
  • Efficiency4 mi/kWh

Result

  • Charging time45 h 23 min
  • Energy added54 kWh
  • Grid energy drawn63.5 kWh
  • Range gained216 mi
  • Average rate5 mi of range per hour

A full charge takes about 45 hours, adding only around 5 miles of range per hour. Level 1 suits drivers who cover 30–40 miles a day and can plug in for 8–10 hours every night.

Level 2 home charger overnight

An 82 kWh EV on a 7.7 kW (32 A) home charger, topping up from 30% to 90%, at 3.6 mi/kWh.

Inputs

  • Battery capacity82 kWh
  • Starting charge30 %
  • Target charge90 %
  • Charger power7.7 kW
  • Charging efficiency90 %
  • Efficiency3.6 mi/kWh

Result

  • Charging time7 h 6 min
  • Energy added49.2 kWh
  • Grid energy drawn54.7 kWh
  • Range gained177 mi
  • Average rate25 mi of range per hour

About 7 hours, adding roughly 25 miles of range per hour – comfortably done overnight. A 48 A charger would only help if the car's onboard charger accepts more than 7.7 kW.

DC fast charging on a road trip

A 77 kWh EV at a 150 kW DC fast charger from 10% to 80%, at 95% efficiency and 3.3 mi/kWh.

Inputs

  • Battery capacity77 kWh
  • Starting charge10 %
  • Target charge80 %
  • Charger power150 kW
  • Charging efficiency95 %
  • Efficiency3.3 mi/kWh

Result

  • Charging time0 h 23 min
  • Energy added53.9 kWh
  • Grid energy drawn56.7 kWh
  • Range gained178 mi
  • Average rate470 mi of range per hour

At a constant 150 kW this would take about 23 minutes. Real sessions are usually longer because the car draws peak power only at low charge and tapers as it fills, so plan on half an hour or more and check your car's published 10–80% time.

Charging levels and typical power

Power figures are typical; check both the charger's rating and your car's onboard charger (AC) or maximum DC rate.

Common EV charging levels
Charging levelSupplyTypical powerRange added per hour (3.5 mi/kWh, 85–90% efficiency)
Level 1120 V outlet, 12 A1.4 kWAbout 4–5 miles
Level 2 (US home)240 V, 32 A7.7 kWAbout 24 miles
Level 2 (US home)240 V, 48 A11.5 kWAbout 36 miles
UK/EU single-phase wallbox230 V, 32 A7.4 kWAbout 23 miles
EU three-phase wallbox400 V, 16 A11 kWAbout 35 miles
DC fast chargingPublic station50–350 kWLimited by the car's charge curve

Why fast charging slows after 80%

Lithium-ion batteries accept high current when they are low and progressively less as cells approach full, to limit heat and protect battery life. Most cars hold near-peak DC power up to somewhere between 30% and 60%, then taper; the last 20% can take as long as the first 60%. On road trips, charging from about 10% to 60–80% and moving on is usually faster overall than waiting for 100%. Preconditioning the battery on the way to a charger, if your car supports it, raises the rate in cold weather.

Planning a home charger installation

  • Circuit size: US electrical code treats EV charging as a continuous load, so the circuit must be rated at 125% of the charging current – a 32 A charger needs a 40 A breaker and a 48 A charger a 60 A breaker. Use the wire gauge ampacity calculator as a starting point and have a licensed electrician do the work.
  • Daily need: divide your daily miles by mi/kWh to get kWh per day. Forty miles at 3.5 mi/kWh is about 11.4 kWh – under two hours on a 7.7 kW charger.
  • Running cost: the grid energy figure times your rate is the cost of the session; the electricity cost calculator handles time-of-use rates.

How to use the EV Charging Time Calculator

  1. 1Enter the usable battery capacity in kWh from your car's specifications.
  2. 2Enter the starting and target state of charge as percentages – 80% is a common daily target.
  3. 3Enter the charging power: the lower of the charger's rating and your car's maximum AC or DC rate.
  4. 4Keep efficiency at 90% for Level 2, use about 85% for Level 1 and 92–95% for DC, then read the time and range added.

Frequently asked questions

How long does it take to charge an electric car?

From 20% to 80% on a 7.7 kW home charger, a 75 kWh battery takes about 6.5 hours. The same top-up on a standard 120 V outlet takes more than a day, while a DC fast charger can do it in under an hour.

How long does an EV take to charge on a regular outlet?

A 120 V outlet supplies about 1.4 kW, adding roughly 4–5 miles of range per hour. A full charge of a mid-size battery can take two days or more.

Why is my car charging slower than the charger's rating?

The car's onboard charger (for AC) or its maximum DC rate may be lower than the charger's, the battery may be cold or nearly full, or the station may be sharing power between cars.

Should I charge my EV to 100%?

Many manufacturers recommend about 80–90% for daily use and 100% only before long trips, though some battery chemistries such as LFP are designed to be charged to 100% regularly. Follow your owner's manual.

Does a higher-amp home charger always charge faster?

Only up to your car's onboard charger limit. If the car accepts 7.2 kW, a 48 A (11.5 kW) charger will charge it no faster than a 32 A one.

References

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