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Home vs public EV charging cost

By RoadCost Editorial4 min readUpdated

A public charger can look cheap per kWh until you add a session fee. A home tariff can look cheap until you include standing charges or a separate meter. A fair comparison uses the all-in cost of the energy you actually need.

Quick answer

Compare all-in cost per kWh: price per kWh plus any session fee divided by the energy purchased, and adjust for charging losses. Then compare convenience and speed separately.

In this guide

  1. 1. The all-in cost
  2. 2. Include losses
  3. 3. Beyond the rate
  4. Questions

Key takeaways

  • A session fee can dominate a small charge.
  • Use all-in cost, not the headline rate.
  • Home charging is not automatically cheapest for every driver.

The all-in cost

If a charger costs 0.40 per kWh and adds a 2.00 session fee for 20 kWh, the all-in cost is 0.40 + 2.00 ÷ 20 = 0.50 per kWh. For 40 kWh, the fee adds only 0.05 per kWh.

Small charges are therefore more sensitive to fixed fees. That is why a quick top-up can look expensive compared with a full charge.

all-in cost per kWh = price per kWh + (session fee ÷ kWh purchased)

Include losses

If the price is based on grid energy, you are already paying for losses. If you are comparing with battery energy, apply the charging efficiency before comparing. Keep the boundary consistent.

Beyond the rate

Home charging usually wins on convenience, but installation, standing charges and time-of-use tariffs can change the maths. Public charging may be necessary on a long trip even if it costs more.

Compare the cost of the energy you need for a specific trip, not a national average that may not apply to you.

Questions

Is home charging always cheaper?
Not always. It depends on your tariff, installation cost and the public charging prices available. Compare all-in cost for your own usage.
How do I compare a charger with a session fee?
Divide the session fee by the kWh you expect to buy, then add it to the per-kWh price.
What about free public charging?
Free charging can be good value, but it may be slow, busy or limited. It is not a reliable plan for every trip.

Sources

Try the calculator

EV charging cost calculator

Add price per kWh, losses and a session fee.

Related guides

EV charging losses explained

Why the electricity you pay for is not all stored in the battery, the charging-loss formula, and how to avoid double counting.

EV vs petrol break-even: how to calculate it

Estimate the annual running-cost saving from an EV and the years needed to recover a purchase-price difference.

kWh/100 km explained: the EV version of L/100 km

Learn what kWh/100 km means, how to turn it into cost per 100 km, and how it differs from mi/kWh and battery-side efficiency.

A note on prices and rules

This guide explains arithmetic and units. It does not publish live fuel prices, electricity tariffs or changing tax rules. Use your own price and check official sources for anything that changes.

Page last reviewed: . Formulas are covered by automated tests. Prices are inputs, not live data.