Industry Trends

Amcor vs. Berry Global: A Buyer's Guide to Navigating the Packaging Landscape

It’s Not Just About Sticking on More Stamps

I’ve been handling corporate mail and shipping for Amcor's marketing and sample distribution for over seven years. I’ve personally made (and documented) a dozen significant postage mistakes, totaling roughly $1,200 in wasted postage, reshipments, and delayed samples. The most common culprit? Assuming you can just slap on extra stamps until it "feels" right. Now I maintain our team's pre-mail checklist to prevent others from repeating my errors.

If you've ever stood at the counter with an odd-shaped envelope or a thick package of documents, wondering how many stamps it needs, you know the confusion. The bottom line is there's no single answer—it depends entirely on your mail's weight, size, and destination. Getting it wrong means your mail comes back marked "Postage Due," or worse, it never arrives at all.

The Core Rule: Weight Dictates Everything

First things first: the number of stamps is determined by weight, not thickness or intuition. One Forever stamp covers the first ounce for a standard letter-sized envelope. Every additional ounce costs more.

According to USPS (usps.com), as of January 2025, a First-Class Mail Forever stamp is valued at $0.73. Each additional ounce for a letter costs $0.24.

So, if your envelope weighs 2 ounces, you need $0.73 (first ounce) + $0.24 (second ounce) = $0.97 in postage. That's one Forever stamp ($0.73) plus one additional ounce stamp ($0.24), or other stamp combinations that add up to $0.97.

My Classic Mistake: In my first year (2017), I mailed 500 product sample envelopes that were just over 1 ounce. I used one stamp on each. They all came back a week later with "Postage Due" stickers. The re-shipping cost, plus the delay, was a $450 lesson. I’d eyeballed them instead of weighing one.

Scenario Breakdown: How to Handle Your Specific Mail

Here’s where most advice falls short—it gives one universal tip. But your approach should change based on what you're mailing. Let's break it down.

Scenario A: The Thick Letter or Large Envelope (Flat)

This is your 10-page contract, a small catalog, or a bunch of photos in a 9x12 envelope.

• The Rule: Once your envelope is over 1/4-inch thick, rigid, or isn't rectangular, it may be classified as a "large envelope" (flat). Rates change. You must weigh it.
• What I Do Now: I keep a small digital scale at my desk. For anything that feels hefty, I weigh it. The USPS website or a postage calculator app does the math for me.
• The Surprise: The surprise wasn't the extra cost. It was how often a simple 5-page letter with a small sample inside tipped over into the "flat" category, needing $1.50+ in postage instead of a single stamp.

Scenario B: The Odd-Shaped or Square Envelope

Think wedding invitations, specialty marketing mailers, or any non-rectangular envelope.

• The Rule: Square or unusually shaped envelopes often require an additional "non-machinable" surcharge (currently $0.44). This is on top of the weight-based postage. They can't run through standard sorting machines, so they cost more to handle.
• My Pitfall: I once ordered 200 beautiful square-cornered sample envelopes for a premium client. We put on what we thought was ample postage. Every single one was returned. The non-machinable fee was the deal-breaker we’d missed.
• The Fix: Always add the non-machinable surcharge for square envelopes or those with clasps, strings, or rigid items inside. A trip to the post office for the first one in a batch is worth it to get the exact rate.

Scenario C: The Heavy Package-in-Disguise

This is the envelope that's really a small package—a key product sample, multiple catalogs, or a small item.

• The Rule: If your envelope is over 3/4-inch thick, it's a package (First-Class Package Service), not mail. The pricing structure is completely different and is based on weight and distance (zones). You can't use stamps for packages over 13 ounces; you need to use Click-N-Ship or a retail counter.
• My Costly Lesson: In September 2022, we tried to mail 50 sample kits in padded envelopes with a sheet of stamps. They were all rejected at the post office. The rep explained the thickness rule. We had to repackage and relabel everything as parcels, causing a 3-day production delay and added costs. Looking back, I should have just asked at the counter for the first one.

How to Actually Place the Stamps (The Right Way)

So you've calculated you need, say, three stamps. Where do they go?

1. Primary Spot: The upper right-hand corner is standard. Place the first stamp there.
2. Additional Stamps: If you need more, place them directly to the left of the first stamp, overlapping slightly if necessary. You can also place them on the back flap, but the front is preferred for automated processing.
3. Don't Do This: Don't place stamps over the return address or the delivery address. Don't place them where they might obscure important markings or barcodes the USPS prints.
4. Pro-Tip: If you're using many stamps, consider using a postage meter or buying a single higher-denomination stamp from the USPS website. It's cleaner and reduces the risk of a stamp coming loose. I’m a fan of the $1.00 or $2.00 stamps for heavier flats.

Dodged a Bullet: So glad I started using a thermal label printer for our regular parcel shipments. Almost stuck with stamps and handwritten labels for everything, which would have looked unprofessional and been prone to errors for anything beyond a simple letter.

How to Know Which Scenario You're In: A Quick Checklist

Still unsure? Walk through this:

1. Weigh it. Use a kitchen scale or a cheap postal scale. This is non-negotiable.
2. Measure thickness. Is it over 1/4 inch? Think "flat." Is it over 3/4 inch? Think "package."
3. Inspect the shape. Is it square or rigid? Add the non-machinable fee.
4. Use a calculator. Go to USPS.com/postage-price-calculator or use a trusted app. Input your details—it gives you the exact price.
5. When in doubt, ask. Take one assembled piece to the post office. The clerks are usually happy to confirm the rate. It's a 10-minute trip that can save you days of delay.

In Q1 2024, after the third postage-related delay for marketing kits, I created this exact checklist. We've caught 22 potential postage errors in the past 9 months using it. The $30 scale paid for itself in the first week.

The Real Cost Isn't Just the Stamps

Here’s my final take, from a packaging professional's view: the quality and correctness of your outgoing mail are an extension of your brand. A client who receives a sample with a "Postage Due" sticker or, worse, doesn't receive it at all, forms an immediate impression—and it's not one of reliability or attention to detail.

The value of getting postage right isn't just saving $0.24 on a stamp. It's the certainty. It's knowing your important mail will arrive on time, looking professional. That's worth far more than the few minutes it takes to weigh and calculate properly. Trust me on this one—I've learned the hard way so you don't have to.

Postage rates referenced are as of January 2025; always verify current pricing at USPS.com.