This can actually be life threatening if done without proper tools and working fast fuses. So just use a kill-a-watt or any other such tool for safety! NB they're maybe not 100% exact but good enough to give an estimate.
(Although they also tend to be not very accurate for low current measurements. So this isn't a use case I would recommend them for.)
But these days I just skip the clamp meter and throw Ikea Inspelning zigbee plugs anywhere I want power measurement.