Category Hub8 Specialized Converters

Paper Size Converters & Print Dimension Guides.

Accurately compare international ISO 216 standards (A0 through A8, B-series), North American office sizes (Letter, Legal, Tabloid), commercial mailing envelopes (C4, C5, DL, #10), and large-format poster prints in millimeters, inches, and 300 DPI pixels.

Universal Paper Sizing Engine

Interactive Calculator
ISO-A
Dimensions:210 × 297 mm (8.27 × 11.69″)
North-American
Dimensions:215.9 × 279.4 mm (8.5 × 11″)
Quick Standard Comparisons:
Display Units:
A4 SpecificationsISO-A
Width:210 mm
Height:297 mm
Aspect Ratio:1 : 1.414
Surface Area:0.0624 m² (96.67 sq in)
300 DPI Megapixels:8.7 MP (2481 × 3507)
US Letter SpecificationsNorth-American
Width:215.9 mm
Height:279.4 mm
Aspect Ratio:1 : 1.294
Surface Area:0.0603 m² (93.5 sq in)
300 DPI Megapixels:8.41 MP (2550 × 3300)
Proportional Scale Visualizer

A4 vs US Letter Visual Comparison

A4210 × 297 mm(8.27 × 11.69 in)Ratio 1 : 1.414W: 210 mm (8.27″)H: 297 mm (11.69″)US Letter215.9 × 279.4 mm(8.5 × 11 in)Ratio 1 : 1.294W: 215.9 mm (8.5″)H: 279.4 mm (11″)
Height Delta+17.6 mm+0.69″
Width Delta-5.9 mm-0.23″
Surface Area Diff3.5%A4 is larger
Fit Scale Ratio97.3%To fit US Letter on A4

🖨️Scaling & Printing Guidance

To print US Letter onto A4: Apply a scale factor of 97.3% in your printer software or PDF driver (select “Fit to Printable Area”). This prevents accidental margin truncation on documents crossing regional boundaries.

High-Resolution Printing (300 DPI): Create your raster artwork at 2481 × 3507 px for A4, or 2550 × 3300 px for US Letter for razor-sharp commercial print output.

True Proportional Scale Comparison

A4 vs US Letter Visual Layout

Vector Scaled (1:1 Proportions)
A4210 × 297 mm(8.27 × 11.69 in)Ratio 1 : 1.414210 mm (8.27″)297 mm (11.69″)US Letter215.9 × 279.4 mm(8.5 × 11 in)Ratio 1 : 1.294215.9 mm (8.5″)279.4 mm (11″)

Interactive Vector Scale: A4 (210 × 297 mm) vs US Letter (215.9 × 279.4 mm) true geometric proportions.

Height Delta+17.6 mm+0.69″
Width Delta-5.9 mm-0.23″
Surface Area Diff3.5%A4 is larger
Print Scale Fit97.3%Scale US Letter to fit A4
Dedicated Tools

Paper & Print Converters Directory.

Dedicated cross-standard converters, envelope fold guides, and poster dimension charts.

A3 ⇄ A4

A3 to A4 Paper Size Converter & Scale Ratio

Convert between ISO A3 (297 x 420 mm) and A4 (210 x 297 mm). Includes scaling percentages (70.7% reduction, 141.4% enlargement) and true visual SVG diagrams.

View Specs & SVGExplore →
A4 ⇄ US Letter

A4 to Letter Paper Size & Dimension Guide

Convert between ISO A4 (210 x 297 mm) and North American US Letter (8.5 x 11 in). Compare true scale visual SVG dimensions, margins, and print scaling factors.

View Specs & SVGExplore →
A4 ⇄ US Letter

A4 to US Letter Paper Size Converter

Compare dimensions between ISO A4 (210 x 297 mm) and North American US Letter (8.5 x 11 inches) for printing, document scaling, and borderless margin alignment.

View Specs & SVGExplore →
DL ⇄ #10 Commercial

Standard Envelope Size Chart & Paper Fit Guide

Complete guide to envelope sizes. Compare ISO 269 C-series (C4, C5, C6, DL) and US Commercial (#10, #9, Monarch, A2, A7) envelopes with matching paper fold charts.

View Specs & SVGExplore →
US Legal ⇄ US Letter

Legal vs Letter Paper Size Comparison

Compare US Legal (8.5 x 14 in) vs US Letter (8.5 x 11 in). Learn when to use legal paper, scanning solutions, printer tray setups, and proportional SVG differences.

View Specs & SVGExplore →
US Letter ⇄ A4

Letter to A4 Paper Size Converter

Convert US Letter (8.5 x 11 inches) to international standard ISO A4 (210 x 297 mm). Includes proportional SVG scale, margin adjustments, and PDF scaling tips.

View Specs & SVGExplore →
A4 ⇄ US Letter

Standard Paper Dimensions Chart (ISO 216 & North American)

Complete guide to paper sizes worldwide. Compare ISO 216 A-series (A0 to A8), B-series, ANSI (Letter, Legal, Tabloid), and Architectural sheets in mm, cm, and inches.

View Specs & SVGExplore →
18x24 Medium Poster ⇄ 24x36 Large Poster

Standard Poster Size Chart & Print Dimensions

Standard poster dimensions and image resolutions. Compare 11x17, 18x24, 24x36, 27x40 movie one-sheet, ISO A1, and B1 formats in inches, mm, and 300 DPI pixels.

View Specs & SVGExplore →
√2

The ISO 216 System

Standardized in 1975, the ISO system is used in over 140 countries. Starting with A0 (exactly 1 square meter in area), each subsequent size (A1, A2, A3, A4) is formed by halving the preceding sheet while keeping the aspect ratio identical.

8.5″

The North American Standard

Rooted in historic papermaking traditions, US Letter (8.5 × 11 in) and Legal (8.5 × 14 in) govern offices in the US, Canada, and parts of Mexico. Unlike ISO sheets, their aspect ratios do not scale geometrically when cut or folded.

300

Commercial Print Resolution

Offset presses and digital laser printers require at least 300 DPI (dots per inch) for clean typography and razor-sharp photographic reproduction. Use our pixel calculators to prepare bleed and trim margins accurately.

Dimensional Standards

Global Paper Dimensions & Envelope Reference Charts.

Official ISO 216 metric, North American imperial ANSI, standard envelope capacities, and high-resolution print pixel requirements.

1. ISO 216 A-Series Dimensions (Metric Global Standard)

FormatWidth × Height (mm)Centimeters (cm)Inches (in)Surface AreaTypical Applications
A0841 × 118984.1 × 118.933.1 × 46.81.000 m²Technical drawings, exhibition posters, blueprints
A1594 × 84159.4 × 84.123.4 × 33.10.500 m²Architectural blueprints, charts, banners
A2420 × 59442.0 × 59.416.5 × 23.40.250 m²Notices, diagrams, medium promotional posters
A3297 × 42029.7 × 42.011.7 × 16.50.125 m²Ledgers, double-page spreads, presentations
A4210 × 29721.0 × 29.78.3 × 11.70.062 m²Global standard for letters, contracts, forms, resumes
A5148 × 21014.8 × 21.05.8 × 8.30.031 m²Notebooks, flyers, paperback booklets
A6105 × 14810.5 × 14.84.1 × 5.80.016 m²Postcards, pocket flyers, recipe cards
A774 × 1057.4 × 10.52.9 × 4.10.008 m²Pocket memo pads, mini flashcards
A852 × 745.2 × 7.42.0 × 2.90.004 m²Business card size, merchandise labels, stickers

2. North American Loose Standards & ANSI Series

Standard NameInches (in)Millimeters (mm)ANSI CodeAspect RatioPrimary Uses
US Letter8.5 × 11.0215.9 × 279.4ANSI A1 : 1.294Standard North American office & school documents
US Legal8.5 × 14.0215.9 × 355.61 : 1.647Legal briefs, courtroom filings, real estate contracts
Tabloid / Ledger11.0 × 17.0279.4 × 431.8ANSI B1 : 1.545Spreadsheets, newspapers, newsletters, CAD drawings
Executive7.25 × 10.5184.2 × 266.71 : 1.448Personal executive stationery, corporate letterheads
Half Letter (Statement)5.5 × 8.5139.7 × 215.91 : 1.545Bank statements, invoices, journals, notepads
ANSI C17.0 × 22.0431.8 × 558.8ANSI C1 : 1.294Architectural schematics, engineering plans
ANSI D22.0 × 34.0558.8 × 863.6ANSI D1 : 1.545Large civil engineering and municipal prints
ANSI E34.0 × 44.0863.6 × 1117.6ANSI E1 : 1.294Full-scale structural master blueprints

3. Standard Envelope Sizes & Matching Document Folds

Envelope FormatMillimeters (mm)Inches (in)StandardEnclosed Document Fit
DL Envelope110 × 2204.33 × 8.66ISO 269A4 folded in thirds (letter-fold)
#10 Commercial104.8 × 241.34.125 × 9.5US CommercialUS Letter folded in thirds (standard US business mail)
C4 Envelope229 × 3249.02 × 12.76ISO 269A4 flat (unfolded) or A3 folded once
C5 Envelope162 × 2296.38 × 9.02ISO 269A4 folded in half or A5 flat sheet
C6 Envelope114 × 1624.49 × 6.38ISO 269A4 folded in quarters or A6 postcard
#9 Commercial98.4 × 225.43.875 × 8.875US CommercialPre-addressed return envelopes (slips inside #10)
Monarch98.4 × 190.53.875 × 7.5US ExecutiveExecutive stationery folded in thirds
A2 Announcement111.1 × 146.14.375 × 5.75US Announcement4.25 × 5.5″ quarter-sheet cards, RSVPs
A7 Invitation133.4 × 184.25.25 × 7.25US Announcement5 × 7″ formal greeting cards and wedding invitations

4. Standard Poster & Display Dimensions (with 300 DPI Pixel Requirements)

Poster NameInches (in)Millimeters (mm)Print Pixels (300 DPI)Common Applications
11 × 17″ (Mini Poster)11 × 17279.4 × 431.83300 × 5100 pxBulletin boards, event flyers, lamppost notices
18 × 24″ (Medium / Arch C)18 × 24457.2 × 609.65400 × 7200 pxConcert posters, band merch, framed art prints
24 × 36″ (Large / Arch D)24 × 36609.6 × 914.47200 × 10800 pxRetail store displays, trade show exhibits, photography
27 × 40″ (One-Sheet Movie)27 × 40685.8 × 1016.08100 × 12000 pxOfficial cinema marquee displays, bus stop shelters
ISO A1 Poster23.4 × 33.1594 × 8417016 × 9933 pxEuropean commercial posters, museum exhibitions
ISO B1 Poster27.8 × 39.4707 × 10008350 × 11811 pxInternational concert venues, large format billboards

5. International Document Scaling & Magnification Percentages

Source SheetTarget SheetPrinter Scale FactorFormula / MathPractical Purpose
A3A470.7%Divide by √2 (0.7071)Downscale double-page ledger spread to single standard sheet
A4A3141.4%Multiply by √2 (1.4142)Enlarge standard document to double-size presentation
A4US Letter94.6%Fit height (279.4 / 297)Print European document on US office printer without clipping bottom
US LetterA497.3%Fit width (210 / 215.9)Print American letter on international paper without clipping side margins
US LegalUS Letter78.6%Fit height (279.4 / 355.6)Condense long legal contract onto standard letter page
Frequently Asked Questions

Expert Answers on Global Paper Formats.

Everything you need to know about international document standards, margin cropping, and envelope compatibility.

What is the primary difference between A4 and US Letter?

A4 paper (210 × 297 mm / 8.27 × 11.69 in) is part of the international ISO 216 standard used across Europe, Asia, Australia, and Latin America. US Letter (215.9 × 279.4 mm / 8.5 × 11.0 in) is used primarily in the United States and Canada. A4 is 17.6 mm (0.69 in) taller, while US Letter is 5.9 mm (0.23 in) wider.

Why do ISO paper sizes maintain the √2 aspect ratio?

The German physicist Georg Christoph Lichtenberg recognized that an aspect ratio of 1:√2 (approximately 1:1.4142) has the unique geometric property that halving the sheet along its long edge produces two smaller sheets with the exact same aspect ratio. This allows seamless booklet printing, photocopying, and scaling (e.g., A3 to A4) without distortion or margin shifts.

What size envelope fits an unfolded A4 document?

A C4 envelope (229 × 324 mm / 9.02 × 12.76 in) is specifically designed to hold flat, unfolded A4 sheets. If folding an A4 sheet in half, use a C5 envelope (162 × 229 mm). If tri-folding A4 lengthwise into three sections, use a standard DL envelope (110 × 220 mm).

What resolution (pixels) is required to print A4 or Letter at 300 DPI?

For sharp, professional photographic prints at 300 DPI (dots per inch), an A4 sheet requires 2480 × 3508 pixels (~8.7 megapixels). A US Letter sheet requires 2550 × 3300 pixels (~8.4 megapixels).