Paper bag guide
SOS Bags Explained: #4 to #20 Sizes, Uses and Printing
Where SOS bag numbers come from, which number suits which counter, and how to print on them
Where do SOS bag numbers come from?
SOS stands for self-opening sack, the pasted-bottom bag that pops open with a shake. The numbers are older than most people think. They date from the days when grocers sold sugar and flour loose. A bag was named for the pounds it was meant to hold.
A #6 was the six-pound sugar bag, a #20 the twenty-pound flour bag. The sizes stuck, the sugar did not. Today the number is a size code only. It says nothing about the paper weight or what the bag can carry.
That history explains the odd jumps. There is no #7 or #9 because nobody sold sugar in those amounts. The numbers run #2, #3, #4, #5, #6, #8, #10, #12, #16, #20 and on up for the biggest sacks.
Every mill rounds the dimensions a little differently, so treat the number as a family name and check the inches on the quote.
Which SOS number fits what?
Six numbers cover almost every counter in the country. The table lists them with the front width and height, the counter that uses each one most, and what a single bag usually holds. Width is across the front; the gusset runs from about 3.3 in on a #4 to 5.3 in on a #20.
| Number | Front width × height | Counter that uses it most | What one bag usually holds |
|---|---|---|---|
| #4 | 5 × 9.75 in | Bakery, candy, hardware | One cookie, a bag of candy, a handful of screws |
| #6 | 6 × 11 in | Schools, delis, pharmacies | A packed lunch, a small prescription |
| #8 | 6.1 × 12.4 in | Delis, cafés, bakeries | A sandwich with a drink can, two pastries |
| #12 | 7 × 13.75 in | Pharmacies, takeout, farm stands | A prescription with a leaflet, a soup with sides |
| #16 | 7.75 × 16 in | Takeout, hardware, liquor stores | A loaf, two boxed meals, a bottle |
| #20 | 8.25 × 16.1 in | Delis, takeout, produce stands | A full carryout order, a dozen bagels |
How do you choose between two neighboring numbers?
The gap between numbers is small, and the right pick comes down to the fold. An SOS bag has no handle, so the top is folded over to close it. That fold takes 2 to 3 in of height.
Measure the tallest thing that goes in the bag and add 3 in. If that lands between two numbers, take the larger one. A bag that just fits cannot be folded, and an unfolded sack spills.
Width works the other way. Pick the smallest number whose width clears the item by about half an inch. A narrow item in a wide sack slides around and tears the paper at the corners.
So a 10 in sandwich box wants a #16, while a 6 in deli clamshell is happy in a #8 with room to fold. The paper bag sizes chart lists every number with its gusset.
Lunch and meal bags: #6 and #8
The #6 is the classic school lunch bag, and it still does that job for camps, meal-prep companies and hotel breakfast-to-go programs. A sandwich, a piece of fruit and a juice box fit with room for the fold.
The #8 is the deli lunch. It is a little wider and taller, so a wrapped sub lies flat along the bottom and a drink can stands beside it. Cafés use it for a pastry box with a napkin and cutlery on top.
Both are usually plain brown kraft or white kraft, with a one-color logo on the front panel. A strap handle can be added for lunch programs where children carry the bag home.
If the bag is handed to a child, white kraft with a printed name panel is a kind touch. Our paper lunch bags are quoted in both numbers.
Pharmacy, bakery and hardware: three counters, three numbers
Each counter settles on a main number and one backup. The pattern is similar across the country, and it is a good shortcut for a new business.
Pharmacies run on the #12. It takes a prescription bottle, the leaflet and a receipt, and the folded top keeps the contents private. White kraft is the usual choice because it reads clean.
Bakeries lean on the #4 and #8. The small one takes a single cookie or a muffin, the larger one two pastries or a slice of cake in a box. Brown kraft hides the inevitable crumbs and butter marks.
Hardware stores use the #4 for loose fasteners and the #16 or #20 for boxed fittings and spray cans. These bags are printed with the store name and phone number, since the bag often ends up in a toolbox for weeks.
How does an SOS bag differ from a flat bag or a handle bag?
A flat bag is two sheets joined at the sides and bottom, with no gusset. It holds a thin item and lies flat. An SOS bag adds side gussets and a pasted square bottom, so it stands up and holds bulk.
A handle bag adds twisted or flat handles to a gusseted body and is carried by them. SOS bags are carried under the arm or against the chest, with the top folded.
That carrying style sets a practical limit. Once an order is heavy enough that customers struggle to hold it under one arm, the bag needs handles. For a deli that means two meals; beyond that, a handle bag or a grocery sack with handles is the better choice.
Our grocery bags with handles pick up where the #20 leaves off.
How do you print on an SOS bag?
SOS bags print on the front panel, and sometimes the back. The gussets and the pasted bottom are left clear because the folds run through them. Here is how to set up artwork for a clean result.
- Take the front width from the table and subtract an inch on each side. That is the usable print width.
- Take the height and subtract 3 in at the top for the fold and 2 in at the bottom for the base crease. That is the usable print height.
- On a #8, that leaves a panel of about 4 × 7 in. On a #20, about 6 × 11 in.
- Place the logo in the upper half of that panel, so it shows above the fold when the bag stands on a counter.
- Choose one ink. Black on brown, or a brand color on white, covers most counters. White ink on brown reads well on a pharmacy or bakery bag.
- Add the phone number or web address under the logo at 7 pt or larger, because kraft softens small type.
- Send a vector file and name the ink color. The free proof shows the logo on a drawing of the right number.
Brown or white kraft for SOS bags?
Natural brown kraft is the default for delis, hardware stores, farm stands and anywhere with a workshop or market feel. It hides marks, costs a little less and takes black or white ink well.
White kraft suits pharmacies, candy shops and bakeries that want a clean counter look. Colored inks print true on it, so a brand with a bright logo gets a closer match.
The weight is the same choice on either color. Most numbers up to #12 run around 70–80 gsm kraft. The larger sacks move up to a heavier sheet for bottles and boxed orders. Those are guidance figures, not load ratings.
Both colors are listed on our SOS paper bags page with the numbers we quote most.
What should an SOS bag quote include?
SOS orders are simple, but a few details save a round of emails. Send these with your request and the quote comes back in one go.
- The numbers you want, with a quantity for each one.
- Brown or white kraft, or a mix across the numbers.
- Plain, or printed in one color on the front, with the ink named.
- Whether you need a strap handle on the lunch sizes.
- The tallest item that goes in each bag, if you are unsure of the number.
- Whether you reorder monthly or quarterly, since quantity sets the unit price.
How do you split an order across SOS numbers?
Most counters order two or three numbers at once, and the split should follow sales rather than instinct. Count what leaves the counter for a week and sort it by size.
A deli might find that 70% of orders are a single sandwich in a #8. Another 20% are two-meal orders in a #20, and 10% are a cookie or a drink in a #4. The order follows those shares.
Order the main number for ten to twelve weeks and the others for the same period, so they run out together. One quote covers all of them, and each number is priced on its own quantity.
Printed SOS runs take 4–6 business days after the proof is approved and arrive 2–3 business days later with tracking. Plain sacks skip the proof and go straight to production.
