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EV Charger Sizing Calculator

Which EV charger do you actually need — 3.3 kW single socket, 7.4 kW / 11 kW / 22 kW Type 2, or DC fast charger? Enter dwell time and daily vehicles, get a recommended SKU and count.

Inputs

Result

Recommended charger
Single Socket 3.3 kW
AC slow charge — ideal for overnight home or office parking.
Power required per bay
3.1kW
Working chargers needed
2
EV-capable bays (5% of parking)
3bays
Rule of thumb: install 5–10% of parking as EV-capable (conduit + breaker ready) and 1 working charger per 3 EV-capable bays initially. Over-conduit now — retrofit is expensive.

How this works

Charger power is chosen by how much energy a driver needs and how long they'll stay. A typical EV uses 12–15 kWh per 100 km, so a 30 kWh top-up gives ~200 km of range. Delivering 30 kWh in 1 hour means you need a 30 kW DC fast charger; in 4 hours a 7.4 kW AC charger does it; in 10 hours a 3.3 kW single socket is plenty.

The second variable is throughput — how many vehicles need to charge per day. The calculator uses both inputs to suggest both the power rating and the number of working chargers you need, plus how many EV-capable bays to provision (conduit + DB space) for future expansion.

For the right hardware, see our EV chargers page. For location-specific deployment guides, see EV charging for hotels, malls, hospitals, commercial properties, and offices.

Frequently asked questions

Match the charger to the dwell time: under 1 hour needs DC fast; 2–4 hours (malls, hotels) → 22 kW; 4–8 hours (offices) → 7.4 or 11 kW; 8+ hours (homes, overnight fleet) → 3.3 kW single socket. Higher power costs more capex and runs into demand charges — don't oversize just because you can.
Start with 5–10% of total parking as EV-capable (conduited and breaker-ready). Install working chargers at a 1:3 ratio to EV-capable bays initially. As utilisation climbs, add chargers into the pre-conduited bays — far cheaper than retrofitting later.
EV-capable = conduit and DB capacity reserved, no charger yet. EV-ready = conduit + outlet installed, just needs a charger plugged in. Installed = working charger on the bay. Municipal mandates increasingly require a mix of all three in new construction.
When dwell time is under 1 hour and you need 50–300 km of added range per session. Typical use: highway corridors, fleet depots with quick turnaround, ambulance/on-call doctor bays, and valet-operated top-up at hotels. For most other use cases, AC is cheaper and sufficient.
Yes, any time you have more than 4 chargers on one DB. Load balancing (dynamic current sharing) lets you install 10 × 22 kW chargers on a 40 kW connection — they cooperate automatically. Without it, you either oversize the connection (expensive) or risk tripping the main breaker.

Related pages & tools

EV Chargers (Product Range)

All EV chargers we make — 3.3 kW to 22 kW Type 2, OCPP-compliant.

Learn More →

EV Charging Cost Per KM

Calculate your actual cost-per-km at current tariffs and compare with petrol.

Learn More →

EV Charging Metering Solution

Per-charger revenue-grade kWh measurement — needed for any billing scenario.

Learn More →

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