Need Help Calculating System Amp Draw

Hi, I'm not sure if I'm posting this in the right place but I thought I'd try.

I know this is kind of a newbie question but I'm having trouble calculating the amp draw of my system. I'm running a recording rig and it's hard to tell what some of the gear is pulling. I know Amps are Watts/Volts but I'm confused about what actual wattage is being used (for example, my DAW has a power supply of 850W but the company that made the computer for me says that the way I'm using it, it's probably only pulling 500-600W). Some of the gear, like my monitors, say 230W on the back, but then online it says 90W, so I'm wondering if it's the same kind of thing where the power supply is higher than what's actually being used. I'm looking to add some hardware and don't want to overload the circuit.

Here's what I have, any help appreciated! Thank you.

Microphone Power Supply - 8.4W / 120V = 0.07 Amps

Lavry Black AD11 - 14W / 120V = .116 Amps

Mytek 192 ADC - I can't find any info but I'm guessing similar to the Lavry AD

Lavry DA10 - 0.1 Amps ?
    Voltage 90-264 VAC, Frequency 40-63Hz, Current 0.1A
    Fuse Rating 2.5A “Time Delay”

Computer - 850W Power Supply, probably just using up to 600W / 120V = 5 Amps

Lights - added up all the lightbulbs, it's about 0.75 Amps

KRK VXT6 Monitors - says 230W on the back? which would be 1.9 Amps each. The internet also says 120W and 90W in different places, so I'm confused.

Great River Preamp - says the fuse is 0.75A, not sure if that means it's using that much?

TV - says 1.8A on the back.

I'm wanting to add a compressor and a few additional preamps but it's only a 15A circuit.

Thanks!