The short answer
Many homes don’t need an upgrade at all. A 200-amp service often has room for a 40–48 amp charger, and even a 100-amp panel is frequently workable with the right approach. The deciding factor isn’t the number on your panel — it’s how much of that capacity your current appliances and HVAC already consume.
Before assuming you need expensive electrical work, it’s worth estimating your actual headroom. Often there’s more room than people expect, and where there isn’t, a cheaper workaround usually exists.
How panel capacity actually works
Your electrical service is rated in amps — commonly 100, 150 or 200. Multiply by 240 volts and you get its theoretical capacity, but the usable continuous capacity is about 80% of the rating, because the National Electrical Code limits continuous loads to 80% of a breaker. So a 200-amp service offers roughly 160 amps of continuous headroom and a 100-amp service about 80 amps.
A Level 2 charger runs for hours at a stretch, so it counts as a continuous load and takes a full bite out of that headroom. Importantly, you don’t simply add up every appliance’s nameplate rating — the NEC’s optional method (220.82) applies demand factors because your dryer, oven, air conditioner and charger rarely all run at full tilt at once.
Estimate your headroom
Two quick checks tell you where you stand. The EV panel-fit check gives a fast read on the largest charger your panel can likely support. For a fuller picture — an actual demand figure in amps and a recommended service size — run the NEC load calculator with your square footage and major appliances.
If the result shows comfortable headroom, you can likely install a standard 40–48 amp charger and move on. If it’s tight, the next section matters.
If you’re short on capacity, try these before upgrading
A lower-amperage charger is the simplest fix. Most EVs charge completely overnight at 32 amps, and many owners never need more. Dropping from 48 to 32 amps meaningfully reduces the load against your panel.
EV load-management (power-sharing) devices are the other big lever. They monitor the home’s draw and automatically throttle the charger when other loads spike, so it never pushes the panel over its limit. These often avoid an upgrade entirely and can cost a fraction of new service. Circuit-sharing with an existing 240-volt appliance and simply scheduling charging for off-peak hours are further options.
When an upgrade is genuinely worth it
If your panel is old or physically full, if you’re on a 100-amp service with already-high usage, or if you’re planning to go further — adding a heat pump, an induction range and a heat-pump water heater on top of the EV — then a 200-amp upgrade can be the right call. Upgrading once is cheaper than paying for electrical work twice, and it future-proofs the rest of your electrification.
An upgrade typically means a permit, coordination with your utility, and a licensed electrician; cost varies widely by region and by whether the meter and service drop also change, so get local quotes rather than relying on a national average.