1. What is USPS Letter Postage?

USPS First-Class Mail letter postage is based on weight increments. Letters up to 3.5 ounces can be sent as First-Class Mail, with each weight bracket having a specific rate.

2. How Does the Calculator Work?

The calculator uses current USPS rate tables:

Where:

• \( Weight \) — Letter weight in ounces (0.1-13 oz)
• \( Lookup\_rate \) — Current USPS postage rate table

Explanation: The calculator matches your letter's weight with the appropriate rate bracket in the USPS pricing table.

3. Importance of Correct Postage

Details: Using correct postage ensures your mail is delivered without delays. Insufficient postage may result in return to sender or postage due from recipient.

4. Using the Calculator

Tips: Weigh your letter precisely (including envelope) and enter the weight in ounces. Standard letters (1 oz or less) have the lowest rate.

5. Frequently Asked Questions (FAQ)

Q1: What's the current rate for a 1 oz letter?
A: As of 2023, the rate is $0.63 for the first ounce.

Q2: What's the maximum weight for First-Class Mail letters?
A: 13 ounces is the maximum weight for First-Class Mail letters.

Q3: Do envelope dimensions affect the price?
A: Yes, letters must be rectangular and within size limits (minimum 5"×3.5", maximum 11.5"×6.125").

Q4: Are there additional fees?
A: Non-machinable letters (square, rigid, etc.) may require an additional $0.40 fee.

Q5: How often do rates change?
A: USPS typically adjusts rates annually, usually in January.