EV Charger Load Capacity Calculator
How many charge points a supply can serve, with and without managed charging. The second number is usually considerably larger, and the difference is the commercial argument for load management.
The figure that matters is the first input: capacity actually available for charging, meaning your connection minus what the building already draws at its peak. Using the nameplate rating will give you an answer that trips the supply.
Your numbers
Your connection capacity minus the building's measured peak, not the nameplate rating. Establish this from recorded load data.
The rating of one charge point, for example 7.4 or 22.
Under managed charging, the lowest rate you are willing to deliver when several vehicles charge at once.
Result
Enter your numbers to see a result.
This is arithmetic, not a design. It assumes every installed point may draw simultaneously, ignores phase balance, and takes no account of protection, cable capacity or the distribution board between the supply and the bays. A real bay count comes from a site assessment.
This tool contains no assumed tariffs, costs, utilisation rates or diversity factors. Every figure above is arithmetic on what you entered. Nothing is sent anywhere; the calculation runs in your browser.
What this does not account for
- Phase balance. Single-phase points clustered on one phase can hit a per-phase limit while others sit idle.
- The distribution board, cable routes and protection between the supply and the bays, which can bind before the incomer does.
- Diversity. Not every point draws at once in practice, but an unmanaged design cannot rely on that.
- Any contracted demand limit, which may bind before the physical rating.
- What happens when the load management system is unreachable, which is a safety decision rather than a capacity one.