UKH

I tend to have my desktop on all day, and put to sleep when not being used. I am wondering (1) how much it would be costing me to do this and (2) if turning the pooter on and off might be costing more than leaving it asleep. Any ideas on this?

Type of computer will make a big difference here. Laptops are generally going to be better at low power states than desktops. And different operating systems have different versions of "sleep".

But in general, sleep will still be using some power, almost certainly more than shutting down and starting up again later unless you're talking about very brief intervals.

If you want to retain open documents etc. without using any power there's often an option called "hibernate", which writes the contents of the memory to disk and then shuts down altogether. Then reads the memory back from disk when you power on again. That won't use any power at all but still has some of the advantages of sleep. Sometimes you have to enable this option in power management settings or similar. Or it might have a different name.

Edit: Sorry, missed that you had specified desktop not laptop. But the rest of my answer still makes sense, hopefully. Exact power consumption in sleep will still depend on various components in the desktop. The most precise option would be to buy an energy-monitoring plug. Quite interesting for various appliances.

They are. I measured the sleep power of my little Viewsonic Atom all-in-one PC to be less than 1W.

Thanks for that.

Sleep, perchance to dram.  Aye, there's the grub.

You could always buy a plug in power meter and check it yourself, and other bits of kit around the house.

Maplin used to do one for about £10