EDDM Size Checker
Grab the corner and resize your mailer — watch it pass or fail the USPS Every Door Direct Mail flat rules in real time, and see exactly which rule decides it. The same way we check every piece before it prints.
Qualifies for EDDM
This piece is a valid USPS flat (height 6.5" beats 6.125") and stays within the 15" × 12" × 0.75" maximums. It mails at the flat $0.247 EDDM Retail rate as long as it weighs 3.3 oz or less.
Remember the print panel: the EDDM indicia and "Local Postal Customer" block must sit on the top half of the address side.
Flat EDDM Retail postage per piece — the same whether it’s this size or the 12″ × 15″ max. Bigger prints cost more ink, never more postage.
Paper stock
Jump to a popular size
Must beat at least ONE letter max:
Longer than 10.5″ (yours: 9″)
Taller than 6.125″ (yours: 6.5″)
Thicker than 0.25″ (yours: 0.016″)
Must stay within ALL flat maxes:
Length ≤ 15″
Height 3.5″–12″
Thickness 0.007″–0.75″
Rules from the official USPS EDDM Quick Reference Guide. EDDM Retail also requires pieces to weigh 3.3 oz or less; postage is a flat $0.247 per qualifying piece. We verify every dimension again before printing.
Why "Normal" Postcard Sizes Get Rejected
EDDM only accepts USPS flats — pieces bigger than a letter in at least one dimension. That's why the standard 4" × 6" and 5" × 7" postcards fail, and why the 6" × 9" is the classic trap: it misses the flat thresholds by a quarter inch and gets the whole mailing refused at the counter, after printing is paid for.
The good news: postage doesn't care about size. A qualifying 8.5" × 11" mails at the same flat $0.247 as a 6.5" × 9", so bigger is usually the better buy. The full rules — including folded pieces, square mailers, and weight — are in our EDDM size requirements guide.