How can you tell the value of a stamp that has no value on it?

Question

I have several different postage stamps and am not sure how much postage each carries. Since I do the majority of my communicating on the net, I rarely mail anything.

Answer 1

Take them to the post office they are most likely first week of a rate change and the post office will have record of their values.

Answer 2

Look at the amount on the stamp. A 1 oz letter will need 39 cents of postage or 1 first class stamp. 2 oz will need 64 cents of postage.