1. What is First Class Letter Postage?

First Class Mail is the most common and economical way to send envelopes and lightweight packages. The current rate for a 1 oz First Class letter is $0.60, with $0.24 for each additional ounce.

2. How Does the Calculator Work?

The calculator uses USPS First Class Mail rates:

Where:

• \( 0.60 \) — Base rate for first ounce
• \( 0.24 \) — Additional ounce rate
• \( Weight \) — Weight in ounces (rounded up)

Explanation: The calculator rounds up the weight to the nearest whole ounce for additional postage calculation.

3. Importance of Correct Postage

Details: Using correct postage ensures your mail is delivered without delays. Insufficient postage may result in the mail being returned or the recipient being charged for the difference.

4. Using the Calculator

Tips: Enter the weight of your envelope in ounces (1 oz = 28.35 grams). Select the mail type. For accurate results, weigh your envelope using a postal scale.

5. Frequently Asked Questions (FAQ)

Q1: What's the maximum weight for First Class Mail?
A: First Class Mail letters can weigh up to 3.5 oz. Heavier items must be sent as First Class Package Service.

Q2: How much is postcard postage?
A: Postcards have a flat rate of $0.44 as of current USPS rates.

Q3: What about international postage?
A: International rates are higher and vary by destination. This calculator only covers domestic US mail.

Q4: Do envelope dimensions matter?
A: Yes. Letters must be rectangular, between 5-11.5" long and 3.5-6.125" high. Thickness must be 0.007-0.25".

Q5: When do postal rates change?
A: USPS typically adjusts rates annually. Always check current rates at usps.com.