Find the best combination of stamps for exact postage.

Just enter the denominations of stamps you have available.

As you type, Which Stamps calculates the best combination of stamps to use!

There's no Enter button, because Which Stamps works while you type.

When you start Which Stamps, it remembers the  denominations you used last time.

Exposed!

I have recently uncovered a sinister conspiracy SO secret that even my drinking buddies, er, I mean, conspiracy-researcher colleagues, won't listen any more. But I continue to tell the world while there is still time!

It started innocently. I needed to mail a six-ounce envelope, and found some stamps in the back of my desk drawer: a roll of 32c stamps, a sheet of 13c stamps, and one 17c stamp. Hmm. Which stamps to use?

So at lunch time, I waited in line at the post office. Finally, I reached the front where the clerk was happy to tell me that 6 ounces would cost $1.52. But then I asked if there was any way to make exact postage with the stamps already in my desk. Now he was not so helpful!

I immediately detected a underlying agenda, so I demanded my rights and made quite a scene. The hidden forces sent out the manager, hoping she could keep their sinister plans from unravelling. She asked me to quiet down, and reminded me that other customers were waiting. But I had figured out their little game!

They assumed I would meekly surrender more postage than necessary, and that's 4 or 5 cents in their pockets!

Which Stamps to the Rescue

Now that I use Which Stamps,
(1) I don't waste old stamps,
(2) I don't pay too much, and
(3) I never have any more unseemly scuffles in the lobby of the post office.
 

What exactly does Which Stamps do?

It shows US first-class and media rates (no big deal, I know), and it also calculates which of your stamps to use to make that postage.

Huh?

Suppose you have 3 kinds of stamps: 32 cent, 17 cent, and 13 cent. Type "32 17 13" at the top of Which Stamps. You'll see:

Weight	Cost	Stamps to Use
1 oz	$0.37	(39 = 3x13)
...	...	...
6 oz	$1.52	3x32 + 17 + 3x13

For 1 oz, there is no way to get exactly 37 cents postage, so the best combination, three 13c stamps, is shown in parentheses.

For 6 oz, you can make the exact $1.52 postage with three 32c stamps, one 17c stamp, and three 13c stamps. (Amazing. I did not know that.)

I just pick the biggest stamp that isn't too big, stick it on, and repeat. It's just like making change, right?

No. The "biggest first" approach works for making change, but only because each denomination of coin is at least double the next smaller denomination.  It doesn't work for either of the two examples above.