A 32A charger fills most cars overnight and skips the panel upgrade a 48A unit forces. Why bigger amperage is often the wrong, more expensive buy.
Charger Type
Quick answer: For most drivers, 32A to 40A is the right amperage, and bigger is often the wrong buy. A 32A charger adds roughly 25 to 30 miles of range per hour and fills the average car overnight, on a 40A breaker and thinner, cheaper wire. Going to 48A needs a 60A breaker, thicker copper, a hardwired install, and sometimes a panel upgrade the smaller unit would have skipped. It only pays off if you drive high daily miles and your car actually accepts 48A, since many EVs cap their onboard AC charging at 32A or 40A. Size the amperage to your car and your overnight hours, not to the biggest number on the box.
Best for
Buyers choosing a charger amperage who want to avoid overbuying and the panel upgrade a bigger circuit can force.
Wrong fit
High-mileage drivers with a short charging window and a car that accepts 48A, who genuinely benefit from the top amperage.
Tradeoff
Higher amperage buys you faster refills. It also buys a bigger breaker, thicker wire, a hardwired install, and a higher chance of a panel upgrade, so only buy it if your car and your driving actually use it.
For most drivers, 32A to 40A is the right amperage, and the biggest number on the box is often the wrong buy. A 32A charger adds roughly 25 to 30 miles of range per hour and fills the average car overnight, on a smaller breaker and thinner, cheaper wire. A 48A charger charges faster, but it needs a 60A breaker, heavier copper, a hardwired install, and sometimes a panel upgrade the 32A unit would have skipped.
We don't sell chargers, so we have no reason to talk you into more amps than you use. We save you from buying the wrong one, and overbuying amperage is one of the most common and expensive mistakes in home charging. Here is how to size it to your car and your driving instead of to a spec sheet.
Quick Answer: Amperage Compared
Charger amperage
Breaker required
Typical wire
Power
Range per hour
Install path
32A
40A
#8 copper
~7.7 kW
25-30 miles
Plug-in or hardwired
40A
50A
#8 copper
~9.6 kW
30-37 miles
Plug-in or hardwired
48A
60A
#6 copper
~11.5 kW
37-44 miles
Hardwired only
Wire gauge is typical, not a rule, since the exact copper size depends on wire type, run distance, and temperature rating, which a licensed electrician sizes to NEC. The pattern is what matters: every step up in amperage means a bigger breaker, thicker and pricier wire, and a heavier load on your panel.
Why the Breaker Is Always Bigger Than the Charger
An EV charger is a continuous load, meaning it can run at full power for hours. The National Electrical Code requires the circuit to be rated at 125 percent of that continuous load (NEC 625.42), which is the same thing as saying the charger can only use 80 percent of its breaker. That is why a 32A charger needs a 40A breaker, a 40A charger needs a 50A breaker, and a 48A charger needs a 60A breaker. It is not padding, it is the code that keeps the wire from running hot for hours.
This is also why a plug-in charger on a NEMA 14-50 outlet caps at 40A: the outlet sits on a 50A breaker, and 80 percent of 50 is 40. To pull 48A you must hardwire onto a 60A circuit. So the amperage you choose partly decides your install path, which is covered in hardwired vs plug-in.
The Two Ceilings That Make 48A Pointless for Many Buyers
Before you pay for 48A, check two things, because for a lot of buyers the extra amps do nothing.
Your car's onboard charger. The charger on your wall can only deliver what the car's onboard AC charger accepts. Many EVs cap their onboard AC charging at 32A (7.7 kW) or 40A (9.6 kW), not 48A. If your car maxes at 32A, a 48A wall charger charges at 32A anyway, and you paid for amps, wire, and possibly a panel upgrade you can never use. Check your car's max AC charge rate in the manual or specs before you buy amperage. This is the single most overlooked number in home charging.
Your overnight hours. Even if your car accepts 48A, ask whether you need the speed. A 32A charger puts back 25 to 30 miles every hour, so a full overnight replaces 250 to 350 miles, far more than almost anyone drives in a day. The faster charger fills an empty battery sooner, but if the car sits all night anyway, "sooner" buys you nothing. Fast charging matters when your window is short, not when you have ten hours.
Why Bigger Amperage Costs More Than the Charger
The charger price barely changes between amperages. The install price changes a lot. Step up to 48A and you are paying for:
A 60A breaker instead of a 40A one
Thicker copper wire, typically #6 instead of #8, which costs more per foot and is harder to pull
A hardwired install, since 48A cannot go plug-in
A bigger continuous load on your panel, which raises the odds of a panel or service upgrade
That last one is the expensive trap. A 48A charger counts as 60A of demand on your load calculation, while a 32A charger counts as 40A. On a tight 100A or 150A panel, that difference is sometimes exactly what tips you from "no upgrade needed" to a $1,500 to $4,000 service upgrade. Choosing 32A instead of 48A can be the move that avoids the biggest line on the invoice. That connection is spelled out in do I need a panel upgrade for an EV charger.
When 48A Is Actually the Right Call
Bigger amperage is not always wrong, and pretending it is would be its own mistake. 48A earns its cost when:
You drive high daily miles with a short charging window. If you routinely put 80 or 100+ miles on the car and it is only home for a few hours, the faster refill is real and useful. This is the buyer 48A was made for.
Your car accepts it and your panel has room. If your EV's onboard charger takes 48A and your 200A panel has plenty of headroom, the extra speed is nearly free to add, so there is little reason not to take it.
You run two EVs. Two cars sharing a charging window benefit from the speed, often paired with load management so the panel can serve both.
If that is you, 48A is a smart buy, not an indulgence. Pair it with a hardwired unit from best home EV chargers and a proper 60A circuit.
How to Size Your Amperage
Step one, check your car's max AC charge rate. This is your ceiling. Do not buy more amps than the car accepts. If it caps at 32A, buy a 32A or 40A charger and stop.
Step two, look at your daily miles and overnight hours. Under 40 daily miles with a full overnight? 32A is plenty. High miles or a short window? Step up.
Step three, check your panel. If your panel is tight, a smaller amperage may avoid a panel upgrade. Run it through the cost and can-my-panel-handle-it estimator and confirm with an electrician's load calc.
Step four, buy a charger that can be set. Many chargers let the electrician set the amperage during install, so you can buy a 48A-capable unit and run it at 32A or 40A today, then raise it later if your car or panel changes. That flexibility costs little and keeps your options open.
For most drivers, 32A to 40A is the right choice. A 32A charger adds 25 to 30 miles of range per hour and fills the average car overnight on a smaller breaker and thinner wire. Go to 48A only if you drive high daily miles, have a short charging window, and your car actually accepts 48A, since many EVs cap onboard AC charging at 32A or 40A. Bigger amperage means a bigger breaker, thicker copper, a hardwired install, and a higher chance of a panel upgrade.
Do I need a 48 amp charger?
Probably not. A 48A charger only helps if your car's onboard charger accepts 48A and you need the faster refill because you drive high miles with a short window. Many EVs cap at 32A or 40A, so a 48A wall unit would charge them no faster while costing more to install. Check your car's max AC charge rate first. If it is 32A or 40A, buy to that number and save the money.
What size breaker does a 40 amp EV charger need?
A 50A breaker. An EV charger is a continuous load, and NEC 625.42 requires the circuit rated at 125 percent of the charger's load, so a 40A charger needs a 50A breaker. By the same rule, a 32A charger needs a 40A breaker and a 48A charger needs a 60A breaker. The charger always uses 80 percent of its breaker, which is why the breaker is bigger than the charger's rated amps.
Will a higher-amperage charger charge my car faster?
Only up to your car's limit. The wall charger can never deliver more than the car's onboard AC charger accepts, so a 48A charger on a car that caps at 32A still charges at 32A. If your car accepts the higher rate, then yes, more amps means more miles per hour. If it does not, the extra amperage just adds install cost with no speed benefit. Check your car's max AC charge rate before buying amps.
Can choosing a lower amperage help me avoid a panel upgrade?
Yes, and it is one of the best ways to do it. A 48A charger counts as 60A of demand on your load calculation, while a 32A charger counts as 40A. On a tight 100A or 150A panel, that smaller load can be the difference between needing a $1,500 to $4,000 service upgrade and not needing one. If your driving fits 32A, choosing it over 48A can save you the biggest line on the invoice.
How many miles per hour does each amperage add?
Roughly 25 to 30 miles per hour at 32A, 30 to 37 at 40A, and 37 to 44 at 48A, depending on your car's efficiency. Even the slowest of these, 32A, replaces 250 to 350 miles over a full overnight, more than almost anyone drives in a day. That is why overnight charging makes 32A enough for most drivers, and why the faster rates only matter when your charging window is short.
Methodology
These guides are built from manufacturer documentation, public specifications, primary research where safety claims matter, and repeated buyer questions that show up in real ownership and installation decisions.
Manufacturer responses can clarify pricing bands, warranty terms, support footprint, or common mistakes. They do not move a page up the shortlist on their own.
