Where do I get a thing that tells me how many watts my PC is munching? Also, what's that thingy called?

Also, once I have my watts figure, how do I convert that into KWH used per year so that I can figure out how much 'leccy I'm paying.

TIA from a non-'leccy/maths aware person.

Virtually all online shops I've seen call them different things, but this is what you're looking for I think:
CLICKY

To work out how much energy something is using in kWh, multiply the figure in Watts by 10^-3 to get power draw in kW

Finally, assuming it's on all day every day for a year, multiply this by 24, then by 365.25, and you have your annual energy consumption in kWh.

You can obviously simplify this down to multiplying by 8766


The figure you get then needs to be multiplied by the rate your electricity supplier (or "leccy" company if you prefer) charges you per kWh. They might do something irritating like vary the rate according to the time of day, but that is (like many things) beyond my control.

Have fun!

You never know, the above product may be able to do most of this for you.

EDIT: "revised" my calculations.

To work out how much you pay:

M = (P * T * C) / 100

M: Monthly cost (In pounds)
P: Device's power (In Kilowatts)
T: Time it is on per month (In hours)
C: Cost per kWh (In pence)

For example, my computer uses 500 Watts and is on for 300 hours a month, so it would use 150 kWh. I pay 10p per kWh, so it costs me £15.00 a month.

Hope that makes sense!

Peter.

Are you sure about that?

If my device used 1 kW and I left it on for an hour, it would use exactly 1 kWh of electricity. Using your method, it would use 3600 kWh, which is a hell of a lot more!

Peter.

You're absolutely right, I've converted kWh to Joules there for some reason. Joules are an infinitely better unit of energy, and I'm just used to using them - electricity co.s seem to be the only ones in the world who use the vile kWh for anything.