Briefcase Dimensions: Standard Sizes and What Fits Inside
A briefcase has to take two awkward shapes at once: a laptop and a stack of documents. These are the standard outside sizes for each style, and the interior you need for letter, legal and A4 paper with a laptop of any size.
A standard soft briefcase measures about 16 × 12 × 4 in (41 × 30 × 10 cm), enough for a 15.6-inch laptop and letter-size files. A classic hard attaché case is 18 × 13 × 4 in (46 × 33 × 10 cm), also made 3 and 5 in deep. For files alone, the inside must be at least 12 × 10 in (30 × 25 cm) for letter folders or about 15 in (38 cm) wide for legal.
- Soft briefcase
- 16 × 12 × 4 in
- Attaché case
- 18 × 13 × 4 in
- Slim briefcase
- 2–3 in deep
- Letter files need
- 12 × 10 in inside
On this page
Standard briefcase sizes by style
Briefcase styles are defined less by brand than by construction: a hard frame fixes the size exactly, while a soft case gives you an inch or two of flex. Dimensions below are outside width × height × depth.
| Style | Size (in) | Size (cm) | Laptop up to | Typical use |
|---|---|---|---|---|
| Slim briefcase / document case | 15–16 × 11–12 × 2–3 | 38–41 × 28–30 × 5–8 | 14–15.6 in | Laptop, a few folders, no extras |
| Standard soft briefcase | 16 × 12 × 3–4 | 41 × 30 × 8–10 | 15.6 in | Daily office carry |
| Hard attaché case | 18 × 13 × 3, 4 or 5 | 46 × 33 × 8, 10 or 13 | 15.6 in in most | Contracts, presentations, a laptop on its own shelf |
| Expandable / double-gusset | 16–17 × 12 × 5–7 | 41–43 × 30 × 13–18 | 16 in | Laptop plus a day's papers, charger and lunch |
| Pilot or catalog case | 17–18 × 13–14 × 7–9 | 43–46 × 33–36 × 18–23 | 16–17.3 in | Heavy document loads; top-opening box shape |
| Wheeled briefcase | 16–17 × 13–14 × 7–9 | 41–43 × 33–36 × 18–23 | 15.6–17.3 in | Sales calls, travel; often sized as an underseat bag |
What size briefcase you need for your documents
Documents are what force a minimum interior size. A sheet lies flat inside a briefcase in landscape orientation, and folders are larger than the paper inside them.
| Document | Paper size | Folder size | Inside width × height needed |
|---|---|---|---|
| US Letter | 8.5 × 11 in (216 × 279 mm) | 9.5 × 11.75 in | 12 × 10 in (30 × 25 cm) |
| A4 | 210 × 297 mm (8.27 × 11.69 in) | usually 1–2 cm larger than the sheet each way | 12.6 × 9.8 in (32 × 25 cm) |
| US Legal | 8.5 × 14 in (216 × 356 mm) | 9.5 × 14.75 in | 15 × 10 in (38 × 25 cm) |
| Ring binder, letter, 1–2 in | 8.5 × 11 in sheets | about 11.5 × 10–11.5 in, 1.5–2.5 in thick | 12 × 12 in, 3 in deep |
A4 folders vary more in size than US folders; measure the ones you use. Paper sizes and their ISO and ANSI definitions are on the paper sizes guide and the A4 size page.
For depth, standard 80 gsm (20 lb) copy paper is about 0.1 mm thick, so 1 in (2.5 cm) of depth holds about 250 sheets. A briefcase 3 in deep with a laptop in its sleeve has room for roughly 1 to 1.5 in of paper, or 250 to 375 sheets in folders.
Briefcase size for a laptop and files
A laptop sleeve inside a briefcase needs about 1 cm (0.4 in) of clearance around the laptop body, and the case structure adds roughly 1.5 in (4 cm) to the outside width. The width of the laptop or the folders, whichever is greater, sets the briefcase width.
| Laptop | Sleeve needed (inside) | Briefcase outside | Depth |
|---|---|---|---|
| 13 to 13.6 in | 12.4 × 8.9 in (31.5 × 22.5 cm) | 14.5–15 × 11 in | 2.5–3 in (slim) |
| 14 in | 13.2 × 9.3 in (33.5 × 23.5 cm) | 15–16 × 11–12 in | 3–4 in |
| 15.6 to 16 in | 14.6 × 9.8–10.2 in (37 × 25–26 cm) | 16.5–17 × 12 in | 3.5–4 in |
| 17.3 in | 16.1 × 10.6 in (41 × 27 cm) | 18 × 13 in | 4–5 in |
Not every briefcase labeled "15.6 inch" has a 37 cm sleeve; check the sleeve's listed inside size against your laptop's spec-sheet width. The laptop bag size chart lists compartment sizes for every laptop class, including thick gaming models that need extra depth.
The inside of an 18 × 13 in attaché case is about 17 × 12 in (43 × 30 cm) once you subtract the frame. That takes a 15.6-inch laptop easily, but a 17.3-inch laptop (up to 40.1 × 29.3 cm) only if the lid organizer and pen loops do not intrude. Check the stated interior.
Choosing the depth
- 2 to 3 in (5 to 8 cm): a laptop or tablet and one or two folders. Looks sharp, but adding a charger or a book makes it bulge.
- 3.5 to 4 in (9 to 10 cm): the everyday standard. A laptop, a charger, a notebook and 100 to 200 sheets of paper.
- 5 in (13 cm) or expandable: a second gusset for papers separate from the laptop, plus space for lunch, a water bottle or a jacket layer.
- 7 in (18 cm) and up: pilot cases and wheeled briefcases, for full binders, product samples or an overnight change of clothes.
Briefcases on planes and in the office
Airlines treat a briefcase as a personal item. A standard 16 × 12 × 4 in case fits under the seat on every major airline, and its slim profile leaves foot room. Rolling briefcases of about 16–17 × 13–14 × 8 in are sized for American's 18 × 14 × 8 in limit but are too tall for United's 17 × 10 × 9 in personal-item size; deeper models need to go in the overhead bin as your carry-on. Full limits are on the carry-on rules by airline page.
At US airport security, take the laptop out unless the briefcase has a checkpoint-friendly laptop section that opens flat with nothing else in it, or you are in a TSA PreCheck or CT-scanner lane.
For a bag worn across the body rather than carried by the handle, compare messenger bag sizes; for storing files rather than carrying them, see filing cabinet dimensions.
Frequently asked questions
What are the dimensions of a standard briefcase in the USA?
About 16 × 12 × 4 in (41 × 30 × 10 cm) for a soft leather or nylon briefcase, and 18 × 13 × 4 in (46 × 33 × 10 cm) for a hard-sided attaché case. Both are sized around US letter paper (8.5 × 11 in) in standard folders (9.5 × 11.75 in).
How big does a briefcase need to be for a laptop and files?
Take the larger of the laptop sleeve and the folders, then add about 1.5 in (4 cm) of width for the case structure. With a 14-inch laptop and letter folders, that is about 15–16 × 11–12 in outside and at least 3.5 in (9 cm) deep. With a 15.6 or 16-inch laptop, 16.5–17 × 12 in.
What are ideal attaché case dimensions?
18 × 13 in (46 × 33 cm) on the outside is the classic size, which gives roughly 17 × 12 in inside: room for letter or A4 folders lying flat and most laptops up to 15.6 in. Choose a 3 in (8 cm) depth for documents and a tablet, 4 in for a laptop and files, and 5 in if you also carry a charger, lunch or a notebook stack.
Does a briefcase count as a personal item on a plane?
Yes. Airlines list briefcases among acceptable personal items, and a 16 × 12 × 4 in briefcase fits under the seat on every major US airline. A wheeled briefcase of 16–17 × 13 × 8 in is closer to the limit and may not meet United's 17 × 10 × 9 in personal-item size.
What size briefcase for legal-size documents?
Legal paper is 8.5 × 14 in and legal folders are about 9.5 × 14.75 in, so the inside needs to be at least 15 in (38 cm) wide. That means an outside width of about 16.5 to 18 in, which most attaché cases and large briefcases have.