The Secret to Handling Odd EDDM Bundle Sizes, Finally Explained

The problem: routes are never round numbers

You picked your routes in the EDDM mapping tool and they came back at 512, 437, and 689 delivery points. USPS wants your postcards in bundles of 50 to 100 pieces, with a facing slip on each bundle stating the count.

512 doesn't divide into 50s. Neither does anything else the mapping tool will ever give you. Every operator hits this on their first self-fulfilled drop, and the USPS documentation explains it about as clearly as USPS documentation explains anything.

Here's the whole system.

The rule that makes odd numbers easy

Each bundle must contain between 50 and 100 pieces. That range is the entire trick — the last bundle doesn't need to match the others, it just needs to land inside it.

So for any route:

1. Divide the route count by 50 and drop the remainder.
2. If the remainder is zero, you're done — all bundles of 50.
3. If not, make one fewer bundle of 50 and fold the remainder into the last bundle.

A 512-piece route: 512 ÷ 50 = 10 bundles with 12 left over. Twelve is below the 50-piece minimum, so it can't be its own bundle. Make 9 bundles of 50 and one bundle of 62. Every bundle is inside the 50–100 window.

A 437-piece route: 8 bundles of 50 and one of 37 fails the minimum. Make 7 bundles of 50 and one of 87.

A 689-piece route: 13 bundles of 50 and one of 39 fails. Make 12 bundles of 50 and one of 89.

That's it. That's the secret. One slightly fat bundle per route.

What goes on the facing slip

Every bundle gets a facing slip — USPS Form 6-1-A, downloadable from the EDDM Retail page — placed on top, facing up. Each slip states:

• The route number (e.g., C012)
• The number of pieces in that bundle — which means your one odd bundle gets its own count, not the count everything else uses
• The total pieces for the route
• Your information as the mailer

Print the slips before bundling day. Filling out thirty facing slips by hand at the counter, while a line forms behind you, is a rite of passage nobody needs.

Bundle with rubber bands, both directions. Cards shifting under the band is the most common reason a clerk asks you to redo a stack.

Count the pieces before you count the bundles

The bundling math above only works if your piece counts are right, and there are two places they go wrong:

Printers ship overage. Ordering 5,000 usually delivers 5,050–5,150. Don't mail the extras into your bundles — counts that don't match the paperwork are a rejection waiting to happen. Keep overage for advertiser proof copies, renewal visits, and framing your first card. You'll want them.

The retail limit is real. EDDM Retail caps you at 5,000 pieces per zip code per day. If your routes total more than that in one zip, you're either splitting the drop across days or you're set up for the BMEU instead. Know which before you drive.

The paperwork that goes with the bundles

Alongside the facing slips, you'll bring:

• PS Form 3587 (the EDDM Retail mailing statement) — route numbers, piece counts, and postage math. At the current 26¢ EDDM Retail rate, a 5,000-piece drop is $1,300, and the form needs to agree with your bundles exactly.
• Proof of the route counts — a printout or screenshot of your EDDM tool order.
• Payment — and note that some post offices still won't take a card for large EDDM transactions. Call ahead.

Take the mailing to the post office that delivers those routes, not the one nearest your house. The retail unit that owns the route is the one that accepts the drop.

Or skip all of it

Everything above is roughly an afternoon the first time and an hour or two once you've done it twice. Whether that's worth doing yourself is a real question with a real number attached: full-service fulfillment — someone else bundles, slips, forms, and drops — costs about $390 on a 5,000-piece mailing over DIY.

Early on, when cash is tight and you haven't collected from all fourteen advertisers, learning the counter process yourself is usually the right call — and it makes you noticeably better at explaining EDDM to advertisers. Once your time is worth more selling spots than sorting cardstock, hand it off and don't look back.

New to the program entirely? Start with What is EDDM? for how routes, permits, and pricing work — and the full 9x12 method guide for the business built on top of it.