It depends on the weight and size of your flat rate envelope. The USPS website provides a handy tool to help you determine the amount of stamps you’ll need.
How many stamps does it take to mail a flat rate envelope?
You need $1.
15 worth of stamps to mail a flat rate envelope.
If I have a 2 oz letter how many stamps do I need?
You would need $0.
55 in stamps to mail a 2 oz letter.
Can I use two forever stamps and one additional stamp to mail a flat rate envelope?
Yes this would be sufficient.
How much does it cost to mail a flat rate envelope?
It costs $1.
15 to mail a flat rate envelope.
Can I use three first-class stamps to mail a flat rate envelope?
Yes this would be sufficient.
If I have a 1 oz letter how many stamps do I need?
You would need $0.
50 in stamps to mail a 1 oz letter.
Can I use one forever stamp and two additional stamps to mail a flat rate envelope?
Yes this would be sufficient.
Can I use four additional stamps to mail a flat rate envelope?
Yes this would be sufficient.
I have a 2 oz letter and $0.
60 in stamps.
Can I mail it?
Yes this would be sufficient.
Can I use one forever stamp and one additional stamp to mail a 1 oz letter?
Yes this would be sufficient.
Can I use two first-class stamps to mail a 1 oz letter?
Yes this would be sufficient.
I want to mail a flat rate envelope and I have three additional stamps.
Can I do this?
No you would need $0.
15 more in stamps.
If I have a 3 oz letter how many stamps do I need?
You would need $0.
75 in stamps to mail a 3 oz letter.
Can I use one forever stamp and four additional stamps to mail a flat rate envelope?
Yes this would be sufficient.
I want to mail a letter that weighs 1.
5 oz.
How many stamps do I need?
You would need $0.
65 in stamps to mail a 1.
5 oz letter.