First Class mail is delivered faster by the USPS than Bulk or Standard mail. First Class mail is generally delivered in 1-3 days locally and 3-5 days nationally by the USPS. First Class mail is also more expensive than Bulk Rate mail. Rates are based on size and weight — you can mail up to one ounce at the lowest postage rate. Certain types of mail must be sent via First Class mail, such as invoices, statements, and other personalized mail. First Class mail is also forwarded automatically or returned to the sender if it is undeliverable. First Class mail is generally perceived to be of higher importance by the recipient, so it generally gets looked at more closely by the recipient. First Class Mail can be pre-sorted to qualify for a discounted bulk mail rates, but a minimum of 500 pieces are required.
Bulk (Standard) mail is generally delivered by the USPS in 2-5 days locally and 1 – 4 weeks nationally. Many companies use Standard Mail because it is less expensive than First Class mail. Bulk mail is not automatically forwarded or returned to the sender if it is undeliverable (though you can pay extra to receive these services). Bulk mail rates are also based on the size and weight of the mail piece; in general, you can mail up to 3.3 ounces at the lowest Standard mail rate. There is a minimum quantity of 200 pieces in order to mail at bulk rates.
Non Profit Mail
Non-profit organizations qualify for discounted bulk postage rates. Non profit mail is treated as standard bulk mail and is usually delivered in 2-5 days locally and 1-4 weeks nationally. Authorization by the US Postal Service is required to receive non profit mailing rates, and only applies to Agricultural, Educational, Fraternal, Labor, Philanthropic, Religious, Scientific, Veteran organizations, as well as some political committees.