Envelope M-Weight Chart: Every Size, Broken Down for Print Shops
Helpful Printer Articles
Envelope M-Weight Chart: Every Size, Broken Down for Print Shops
If you’ve ever quoted shipping, estimated postage, or tried to figure out how many envelopes fit in a box, you’ve probably run into m-weight. It’s a small detail that can make a big difference—especially when your shipping estimate is suddenly off by twenty pounds.
M-weight is the weight of 1,000 sheets or envelopes of a specific size and stock. The “M” stands for 1,000. Print shops rely on this number to calculate paper costs, freight, and postage, since most pricing is based on thousands—not single pieces.
Below, you’ll find a complete m-weight chart for standard envelope sizes, organized by seam type: open side and open end. We’ve included the paper weight (like 24 lb or 32 lb) for each size, since m-weight shifts with different stocks.
Envelope M-Weight by Size Chart
| Number | Size | Substance | Weight per M |
|---|---|---|---|
| No. 8 | 3-5/8" x 6-1/2" | 24 lb | 8 lbs |
| No. 8-1/2 | 3-3/4" x 6-3/4" | 24 lb | 8 lbs |
| No. 9 | 3-7/8" x 8-7/8" | 20 lb | 10 lbs |
| No. 9 | 3-7/8" x 8-7/8" | 24 lb | 12 lbs |
| No. T-4 | 4-1/8" x 9" | Window | 13 lbs |
| No. 10 | 4-1/8" x 9-1/2" | 20 lb | 11 lbs |
| No. 10 | 4-1/8" x 9-1/2" | 24 lb | 13 lbs |
| No. 11 | 4-1/2" x 9-5/8" | 24 lb | 16 lbs |
| No. 14 | 5" x 11-1/2" | 24 lb | 20 lbs |
| Library | 3-1/2" x 3-3/4" | Plain | 8 lbs |
| X-Ray | 14-1/2" x 17-1/2" | 24 lb | 72 lbs |
| X-Ray | 14-1/2" x 17-1/2" | 32 lb | 100 lbs |
| — | 1-3/4" x 2-3/4" | 24 lb | 3 lbs |
| — | 2-1/4" x 3-1/2" | 24 lb | 4 lbs |
| — | 2-1/2" x 4-1/4" | 24 lb | 5 lbs |
| — | 3-1/4" x 4-3/4" | 24 lb | 7 lbs |
| — | 3-1/4" x 5-5/8" | 24 lb | 8 lbs |
| — | 3-1/2" x 6-1/8" | 24 lb | 9 lbs |
| — | 3-5/8" x 7-7/8" | 24 lb | 10 lbs |
| — | 4" x 7-1/2" | 24 lb | 10 lbs |
| — | 2-3/4" x 4" | 24 lb | 4 lbs |
| — | 3" x 4-1/2" | 24 lb | 5 lbs |
| — | 3-5/8" x 5-1/2" | 24 lb | 7 lbs |
| — | 3-3/4" x 4-3/4" | 24 lb | 6 lbs |
| — | 4-1/8" x 6-1/8" | 24 lb | 7 lbs |
| — | 4-1/4" x 5-1/4" | 24 lb | 7 lbs |
| — | 4-1/2" x 5-7/8" | 24 lb | 8 lbs |
| — | 4-1/2" x 6-5/8" | 24 lb | 10 lbs |
| — | 4-5/8" x 6-3/4" | 24 lb | 11 lbs |
| — | 5" x 6-1/2" | 24 lb | 11 lbs |
| — | 5-1/2" x 7-1/2" | 24 lb | 14 lbs |
| — | 5-1/2" x 8-1/2" | 24 lb | 16 lbs |
| — | 5-7/8" x 9" | 24 lb | 16 lbs |
| — | 5-3/4" x 9-1/2" | 24 lb | 18 lbs |
| — | 6" x 7-1/2" | 24 lb | 19 lbs |
| — | 6-1/2" x 9-1/2" | 24 lb | 20 lbs |
| — | 7-1/2" x 10-1/2" | 24 lb | 30 lbs |
| — | 7-1/2" x 10-1/2" | Tyvek 14 lb | 21 lbs |
| — | 9" x 12" | 24 lb | 35 lbs |
| — | 9" x 12" | 32 lb | 45 lbs |
| — | 9" x 12" | Tyvek 14 lb | 26 lbs |
| — | 9" x 12" | Expansion | 56 lbs |
| — | 9-1/2" x 14-3/4" | 24 lb | 45 lbs |
| — | 9-1/2" x 14-3/4" | 32 lb | 60 lbs |
| — | 9-1/2" x 14-3/4" | Expansion | 72 lbs |
| — | 10" x 13" | 24 lb | 41 lbs |
| — | 10" x 13" | 32 lb | 55 lbs |
| — | 10" x 13" | Tyvek 14 lb | 32 lbs |
| — | 10" x 13" | Tyvek 18 lb | 40 lbs |
| — | 10" x 13" | Expansion | 64 lbs |
| — | 10-1/2" x 14-3/4" | 24 lb | 51 lbs |
| — | 10-1/2" x 14-3/4" | 32 lb | 68 lbs |
| — | 11-1/2" x 14-1/2" | 24 lb | 51 lbs |
| — | 11-1/2" x 14-1/2" | 32 lb | 68 lbs |
| — | 11-1/2" x 14-1/2" | Expansion | 80 lbs |
| — | 12" x 15-1/2" | Tyvek 18 lb | 56 lbs |
| — | 12" x 16" | 24 lb | 65 lbs |
| — | 12" x 16" | 32 lb | 82 lbs |
| — | 12" x 18" | 24 lb | 84 lbs |
| — | 15" x 18" | 24 lb | 84 lbs |
| — | 15" x 18" | 32 lb | 112 lbs |
| — | 15" x 20" | 32 lb | 141 lbs |
| — | 17-1/2" x 22-1/2" | 32 lb | 175 lbs |
| — | 19-1/2" x 24-1/2" | 32 lb | 200 lbs |
| — | 20" x 27" | 32 lb | 212 lbs |
| — | 24" x 28" | 32 lb | 275 lbs |
How to Calculate Total Envelope Job Weight using M-Weight
To find the actual weight of an order, divide the m-weight by 1,000 and multiply by your quantity. For example, if you’re running 5,000 No. 10 window envelopes at 24 lb, and the m-weight is 13 lbs, your total order weighs 65 lbs.
Keep in mind, this chart uses standard paper weights. If a client requests a heavier or lighter stock, the m-weight will change, so it’s smart to double-check the numbers before you finalize a shipping quote.
Bookmark this chart, or even better, add it to your quoting process so weight estimates become accurate every time.
Why M-Weight Matters for Print Shops
Before we dive into the numbers, here’s why this chart is a tool you’ll want to keep close:
Shipping quotes. Freight carriers price by weight. When you know your order’s m-weight, you can calculate box weight ahead of time and avoid surprises at the shipping counter.
Postage estimates. Mailing services, especially for bulk mail, price by weight per piece. M-weight helps you get accurate numbers quickly.
Stock comparisons. If you’re switching a client from 24 lb to 32 lb stock, the weight of every box changes. This chart shows you exactly how much, so you can plan with confidence.
Storage and handling. Knowing the real weight of a pallet of envelopes helps you plan your warehouse space and stay within equipment limits.
