# Calculating amps required for several devices

I am trying to figure out how many amps are required given a certain number of items that will be plugged into an outlet.

Do I simply add the number of amps that each item takes to come up with a total or does it not work like that?

Full disclosure, I'm going to a trade show and you have to request the number of amps you need. 5, 10, 15, 20.

I'm running 2 laptops, a 32" TV and a 24" monitor.

• Yep, but you should plan on a 20% buffer in your circuit breaker and wiring capacity. They may already do that, but you don't want things tripping mid-show. Commented Jan 25, 2022 at 22:25

Assuming the tv and monitors are LCD/LED then each of those devices will typically use less than an amp each.

Sometimes you need to do a little math, and sometimes manufacturers mix watts and amps. Add the watts for devices listed in watts, divide by volts, add to the amps for devices listed in amps.

The input for the laptop power supplies might say 95 watts, the TV might say 75 watts, the monitor might say 1.0 amps.

So 95+95+75=255w, 255w/120v = 2.125A, plus the 1.0 amp monitor = 3.125A.

The numbers intended on being high estimates, the actual numbers will all be consumption when driving full power, white screens, so actual power consumption should be slightly less.

• I would take a little UPS for the displays to prevent problems in case of overloads and tripping. Commented Jan 25, 2022 at 23:35
• Great info, particularly regarding the high estimates of the amp usage. Thank you. Commented Jan 25, 2022 at 23:53
• @Ryan Yes, things get pretty formal at trade shows, so you need numbers you can rely on if there's shouting (the electrician's union will insist they did right). Commented Jan 26, 2022 at 2:09

Yes, it does work like that. For things with power supply "bricks", look at the current on the input side, not the output.

2 laptops, a TV and a monitor will add up to very little.

• For stuff like heaters, TVs, lights it is okay to just go by the amps/watts. Motors and stuff that uses compressors(AC units,fridges) then need to know of start up amps, which can be five times the running amps, but only for a few seconds. Commented Jan 25, 2022 at 23:45
• @crip659, that would explain why my pond motor blew my GFCI that's hooked to my bathroom... Commented Jan 25, 2022 at 23:53
• @RyanGriffith Most circuit breakers can stand start up amps, unless you are using a hair dryer at the same time. GFCIs usually check if any current on ground wire, so with a pond motor, would be good to check into it for any problems. Commented Jan 26, 2022 at 0:36