Ordering a ring without trying it on first can be tricky, but I am here to help. The very best way to get a good fit on the first try is to have a jeweler size your finger. Obviously, that isn't always possible. You might be tempted to try online size aids, like the strips of paper you wrap around your finger. They don't typically work, and to date, I have yet to see a customer get the right size that way. So, what to do? I can send you a ring sizer by mail, it's a great little gadget, and so far everyone who has used it has gotten a good fit.
Concerning the Knitting Needle Gauge Rings, or any wide bands: even if you know the size you usually wear, if your rings are narrow in the back they may fit differently than a band that is wide all the way around, and it is worthwhile to check your size. The sizers I send out are appropriate for these rings.
If you are planning on sending a ring as a gift, but want to surprise them, I recommend a gift certificate and a ring sizer. Just add a note to the purchase that you would like a ring sizer, and where to send it.
Please email me at natalia@malojos.com with your mailing address, and let me know you would like a ring sizer. I hope this helps!