Quick answer: ANSI A through E are a North American sequence of sheet sizes used for office, engineering and technical drawings. ANSI A is 8.5 × 11 inches; each larger size doubles the area by doubling one side.
Measurement note: dimensions are stated width × height in portrait orientation. Turn the sheet through 90 degrees for landscape use. Millimetres are the controlling values for ISO sizes; inch figures are rounded conversions.
ANSI A to E dimensions
| Size | Inches | Millimetres |
|---|---|---|
| ANSI A | 8.5 × 11 in | 215.9 × 279.4 mm |
| ANSI B | 11 × 17 in | 279.4 × 431.8 mm |
| ANSI C | 17 × 22 in | 431.8 × 558.8 mm |
| ANSI D | 22 × 34 in | 558.8 × 863.6 mm |
| ANSI E | 34 × 44 in | 863.6 × 1117.6 mm |
How the sequence works
The series alternates which side is doubled. Two ANSI A sheets make one ANSI B by area; two B sheets make one C, and so on. Unlike ISO A sizes, the aspect ratio is not constant throughout the sequence.
Uses
- ANSI A for letters, reports and office forms
- ANSI B for newsletters, small drawings and 11 × 17 output
- ANSI C and D for engineering and architectural drawings
- ANSI E for large plans and technical documentation
ANSI versus ISO
The ANSI and ISO systems use different base dimensions and scaling geometry. A drawing template should be created for the actual required standard. Do not rename an A3 file “ANSI B” or assume one will trim cleanly to the other.
Frequently asked questions
Is ANSI A the same as Letter?
Yes in dimensions: both are 8.5 × 11 inches.
Is ANSI B the same as Tabloid?
Yes in dimensions: both are 11 × 17 inches, with Ledger naming the landscape orientation.
What standard should an engineering drawing use?
Use the standard required by the client, authority, contract or drawing-management system. Include the dimensions and revision information in the drawing specification.
Common mistakes to avoid
- Entering rounded inch conversions when exact millimetres are available.
- Confusing finished trim with bleed or parent-sheet dimensions.
- Allowing the printer driver to scale automatically.
- Assuming a named size is identical in every national standard.
- Ordering paper before checking the printer’s minimum, maximum and supported weight.
- Judging readability only on a zoomed computer display.
For ANSI Paper Sizes Explained, the most dependable approach is to retain the standard’s controlling unit, state the dimensions in the purchase order, use a supplier template and approve a full-size proof. This is especially important when the project moves between countries, software packages or production methods.
How to specify the size without ambiguity
For ANSI Paper Sizes Explained, a reliable print specification states more than the familiar format name. Give the finished width and height, measurement unit, orientation, number of pages or panels, paper weight, surface, colour process, bleed, finishing and quantity. This prevents regional names and printer defaults from silently changing this particular job.
- Finished size: write width × height and identify portrait or landscape.
- Artwork size: distinguish the trimmed page from any larger bleed canvas or parent sheet.
- Stock: specify grammage or basis weight, coating, colour and recycled or certified requirements.
- Finishing: state folds, scoring, binding, drilling, corner rounding, lamination or mounting.
- Tolerance: ask the supplier what cutting, folding and registration variation should be expected.
When ordering ANSI Paper Sizes Explained, a short name alone leaves important decisions unstated. A specification such as “finished size as stated above; portrait; 3 mm bleed; 170 gsm uncoated white stock; full colour both sides; scored where shown” is harder to misinterpret. When the format has regional variants, include the governing standard or exact dimensions every time.
Make a full-size physical proof
Screens do not communicate the physical scale of ANSI Paper Sizes Explained reliably. Before a large order, print a representative page at 100%, trim it to the stated size and use it as the finished item will be used. Measure one horizontal and one vertical feature with a ruler. Fold it, place it in its envelope or holder where relevant, view it from the intended distance and ask someone unfamiliar with the design to find the main information.
A proof of ANSI Paper Sizes Explained should check more than spelling. Look for text that is technically present but difficult to read, lines that sit too close to the trim, images whose important details enter a fold or binding area, barcodes or QR codes that do not scan, and stocks that crack or show through. For colour-critical work, a calibrated contract proof or press proof is more informative than an office print.
Sources and standards
The measurements and production guidance in this guide were checked against the following standards bodies, postal operators and print-platform specifications. Standards can be revised or withdrawn, so check the linked record when a contractual or regulated specification matters.