OmniTools

EV Charging Cost Calculator

Cost, time and range added for a charge, from battery size, tariff and charger power.

Basis: Energy added (kWh) = battery capacity × (target − start) ÷ 100; metered energy = energy added ÷ (1 − loss); time = energy added ÷ charger power. Efficiency and loss are your own inputs·2026-09-13 verified·Editorial policy

Before you rely on this

Charging time assumes the charger holds its rated power throughout. Real DC sessions taper sharply above roughly 80% and slow further with a cold battery. The tariff is your own input, so operator membership rates, time-of-use pricing, minimum session fees and parking charges are not included.

Tool Overview & Key Purpose

Turns battery size, charge window, tariff and charger power into what a session costs, how long it takes and how much range it adds. Charging loss is a separate input, so the energy that reaches the battery and the energy the meter bills are shown apart.

Step-by-Step Usage Instructions

1STEP 1

Enter the battery capacity in kWh and the starting and target state of charge.

2STEP 2

Enter the tariff — the per-kWh price from your bill or from the charger screen.

3STEP 3

Check the charging loss. Around 10% is typical for slower AC charging; DC fast charging loses less.

4STEP 4

Pick the charger power and enter your efficiency to see range added and cost per 100 km or 100 miles.

Real-World Scenarios & Practical Cases

3 Practical CasesScenario #1

An overnight charge at home

Taking a 60 kWh battery from 20% to 80% puts 36 kWh in. At 10% loss the meter counts 40 kWh, and at 0.15 per kWh that is 6.

Home charging looks lossy, but the low tariff still makes it the cheapest option by total cost.Scenario #2

A motorway rapid charge

The same 36 kWh on a 150 kW charger is 15 minutes in theory, but the real session takes longer because power tapers as the battery approaches 80%.

On a long trip, stopping at 80% and driving on is usually faster overall than waiting for 100%.Scenario #3

Comparing against petrol

At 5 km/kWh, 36 kWh is 180 km. If the session cost 6, that is 3.33 per 100 km — put it next to what the same distance costs on petrol.

Comparing fuel cost alone understates things; charging time and charger availability belong in the picture too.Energy and cost formula

Energy added (kWh) = capacity × (target% − start%) ÷ 100
Metered energy = energy added ÷ (1 − loss)
Cost = metered energy × tariff
Time = energy added ÷ charger power
Range = energy added × efficiency
The time figure assumes power stays constant throughout.

Pro Tips & Key Considerations

Enter the tariff exactly as the charger or app shows it — member and non-member rates often differ sharply.Efficiency is seasonal. Cabin heating can cut it by 20–30% in winter, so re-run the numbers with that figure.Manufacturers broadly agree that stopping daily charging around 80% is better for long-term battery health.

Frequently Asked Questions (FAQ)

Sources & References

U.S. DOE Alternative Fuels Data Center — Charging at Home U.S. DOE AFDC — Electric Vehicle Charging Speeds and Station Levels