Husband and I will be traveling to Europe, cruising and staying in the UK and Spain. We both use cpap machines (from the US). Can you please tell us what type of converters or transformers we might need to plug in and use our machines?

First look at the sticker on the plug or on the equipment. It should look something like this:

Input: AC100-240v 50-60hz.

And post what you find on this forum.

Equally important: What does it say about "W" or "VA"

As said, if the appliances that you are bringing say 100-240v on the power supplies (typically phone, ipod, camera and laptop chargers), then all you need are the plug adapters NOT converters.

http://www.enjoy-europe.com/hte/chap11/electric.htm

Should you ever run a CPAP machine through a converter?

My Respironics CPAP has been to Norway, London, Paris, Prague and Spain with only an adaptor plug. I would include extension cords for the occasional hotel that doesn't have a plug in a convenient location.

Thanks for your thoughtful replies. The cpaps and phone are good for 100-240v so we'll just need the adapter plug. The extension cord is a great suggestion! We'll be in Madrid, Barcelona, London, and a Holland America cruise ship. Will the same round prong adapter plug work for all?

I don't see any W or VA. Is that important?

>I don't see any W or VA. Is that important?
Only if your items weren't suitable for 240V

London has a different plug, the common 2 prong euro-plug doesn't fit properly. (I've used a euro-plug and a wooden stick.. DON'T do this!)
I'd bet the cruise ship has US and other sockets. But you'd have to ask them.
Your cpap has a 2 prong plug, right?

You can buy a little bag of converter plugs that will have al the various ones you'll need atWal-mart or travel stores for a few dollars. Just takethe whole bag and you'll be set!