Shipping with a Plain White Envelope (PWE) can be a great way to reduce costs for simple, low-value items — but it only works if you follow the correct size, weight, and packaging rules.
Both Drip and the USPS have clear requirements around what qualifies as machinable letter mail. Failing to follow them can lead to mail being returned, postage due notices, delayed deliveries, or unhappy buyers. This guide breaks down the hard limits you must follow when using PWE — and offers tips to help you get it right.
Drip’s PWE Weight Limit: 2 oz Maximum
Drip enforces a strict 2 oz limit for all PWE shipments made through the platform.
This 2 oz limit includes:
The envelope itself
Any cards, stickers, or paper inserts
Penny sleeves, soft bags, or team bags
Backing materials (e.g., thin cardstock)
Why the limit? Staying under 2 oz helps reduce USPS reclassification (to parcels) and keeps shipping affordable and consistent. It also minimizes complaints from buyers receiving bent, bulky, or rejected mail.
📌 Tip: Most single-card shipments in penny sleeves weigh ~0.2–0.3 oz. You can usually ship 1–4 raw cards and stay under 2 oz — but always weigh to confirm.
USPS Letter Mail Size Requirements
To qualify as First-Class letter mail, your PWE must follow these official USPS guidelines:
Requirement | Minimum | Maximum |
Length (long side) | 5 inches | 11.5 inches |
Height (short side) | 3.5 inches | 6.125 inches |
Thickness | 0.007 inches (paper thin) | 0.25 inches (about 6 cards thick) |
Weight | N/A | (Drip max: 2 oz) |
Shape | Rectangular only | Must be flexible |
If your envelope doesn’t meet all of these criteria, USPS may treat it as a non-machinable letter or even a parcel, which means:
Your buyer could receive a postage due notice
The item may be delayed or returned
The shipment may no longer be deliverable under letter-rate postage
🛑 Common disqualifiers: bulky items like toploaders, too many cards stacked tightly, overly rigid packaging, or envelopes sealed with excessive tape
What Happens If You Exceed the Limits?
If your envelope is overweight, oversized, too thick, or inflexible, USPS can:
Return it to sender for additional postage
Apply postage due on delivery (which may frustrate buyers)
Mark the shipment undeliverable if it jams equipment
Delay delivery significantly, especially during high-volume periods
Treat the envelope as a parcel, charging a much higher rate
On Drip, repeated issues with misclassified PWEs may result in:
Shipping violations recorded on your account
Refund enforcement if the buyer doesn’t receive the item
Trust & Safety review if patterns suggest shipping misuse
Tips for Staying Within the Limits
1. Use a Digital Scale
Always weigh your final, sealed envelope before marking the order as shipped. Scales accurate to the tenth of an ounce are inexpensive and help you avoid guesswork.
2. Test Flexibility
Hold the sealed envelope and gently bend it in both directions. If it feels stiff, thick, or springy — it may not qualify for letter rates.
3. Limit Contents
Don’t overstuff. Try to keep it to 1–4 raw cards max, or very thin inserts. Avoid hard plastics, coins, pins, or anything with raised edges.
4. Choose the Right Envelope
Use #9 or #10 envelopes — avoid smaller or custom sizes. Look for ones with smooth seams and enough room to comfortably fit contents.
5. Don’t Seal It Too Rigidly
If you tape or reinforce items inside, be careful not to create pressure points or stiffness. Backing boards are fine as long as the envelope remains flat and flexible.
Bottom Line
To use PWE safely on Drip:
Stay under 2 oz total weight
Follow USPS size and flexibility rules
Don’t include anything rigid or bulky
Test your envelope before you ship
Taking a few extra seconds to check your envelope can prevent delayed delivery, buyer complaints, and shipping violations.
When in doubt, use tracked shipping instead. It protects your buyer experience — and your seller standing — especially for high-value or sensitive items.