Tactile Sign Character Specifications: Height, Stroke Width, and Spacing

Under the 2010 ADA Standards, tactile characters must generally be 5/8–2 inches high (§703.2.5), project at least 1/32 inch above the background (§703.2.1), and have stroke thickness no greater than 15% of character height (§703.2.6). Character proportions, character spacing, border clearance, and line spacing are also governed by §§703.2.4 and 703.2.7–.2.8.

KEY FACTS AT A GLANCE

 Requirement                                                                                                                      Value                                                                  Reference    

Raised character depth                                                                            ≥1/32 in (0.8mm)                                 §703.2.1

Color Specifications(uppercase O width/uppercase I height)        55%-110%                                               §703.2.4       

Raised character height (uppercase I)                                                  5/8-2 in (16-51mm)                           §703.2.5

Reduced character-height exception                                                    ≥1/2 in (13mm)                                     §703.2.5.

Exception Stroke thickness (uppercase I)                                              ≤15% of character height                   §703.2.6

Character spacing                                                                                       ≥1/8 in (3.2mm); ≤4*stroke width     §703.2.7

Clearance from raised borders and decorative elements                 ≥3/8 in (9.5mm)                                  §703.2.7

Line spacing (baseline to baseline)                                                          135%-170% of character height        §703.2.8

 

AT A GLANCE

ADA tactile character specifications govern how raised letters are formed, sized, spaced, and positioned on accessible signs. These requirements help people who are blind or have low vision distinguish characters through touch while ensuring that the lettering follows consistent dimensional rules.

For signage manufacturers and buyers, compliance involves more than choosing an appropriate font or making the letters sufficiently large. Character height, raised depth, stroke thickness, proportions, spacing, and separation from borders must be considered together when preparing artwork and production specifications.

 

What Are the ADA Tactile Character Size Requirements?

Under §703.2.5, raised characters must generally measure 5/8–2 inches high, measured vertically from the character baseline using the height of the uppercase letter "I.”

The permitted height range applies to the tactile characters, not the overall sign panel. The Standards also specify that characters must be uppercase, use a sans-serif font, and avoid italic, oblique, script, highly decorative, or unusual forms (§703.2.2–.2.3). In addition, the width of the uppercase "O" must be 55%–110% of the height of the uppercase "I" (§703.2.4).

An exception permits raised characters as small as 1/2 inch when separate raised and visual characters conveying the same information are provided (§703.2.5). This exception should not be applied automatically to every tactile sign; confirm that the proposed arrangement satisfies the stated conditions.

 

How Much Must ADA Tactile Characters Be Raised?

Under §703.2.1, tactile characters must project at least 1/32 inch (0.8 mm) above the sign background.

This raised depth allows the characters to be distinguished by touch. It is separate from character height: raised depth measures how far the lettering projects from the background, while character height measures the vertical dimension of the letter itself (§703.2.1 and §703.2.5). During fabrication, verify the finished raised characters rather than relying solely on the artwork or nominal material thickness. The final surface should provide clearly distinguishable tactile lettering, and the Standards' advisory guidance recommends avoiding sharp or abrasive edges on characters designed to be read by touch.

 

What Is the Maximum ADA Tactile Character Stroke Width?

Under §703.2.6, the stroke thickness of the uppercase letter "I" must not exceed 15% of the character height.

 Stroke thickness refers to the width of the letter stroke, not the raised depth or the overall width of the character. The requirement helps prevent tactile letters from being formed with strokes that are disproportionately thick relative to their height.

When selecting a font or preparing custom lettering, inspect the actual character geometry rather than relying only on the font's name or visual appearance. The uppercase "I" is the reference character for determining the permitted stroke thickness, so its dimensions should be checked during artwork review and production approval. 

 

What Are the ADA Character Spacing and Border Clearance Requirements?

Under §703.2.7, spacing between adjacent raised characters must comply with minimum and maximum limits based on the characters' cross-sections, and characters must be at least 3/8 inch (9.5 mm) from raised borders and decorative elements.

Character spacing is measured between the two closest points of adjacent raised characters within a message, excluding word spaces. For rectangular cross-sections, the minimum spacing is 1/8 inch (3.2 mm), and the maximum is four times the raised character stroke width. For other cross-sections, separate minimum distances apply at the base and top of the characters, while the same four-times-stroke-width maximum applies at the relevant measurement points.

Line spacing is governed separately by §703.2.8. The distance between the baselines of separate lines of raised characters must be 135%–170% of the raised character height. These rules should be applied to the actual fabricated character geometry, not simply to the spacing values displayed in a digital design file.

 

What Should Be Checked Before Approving Tactile Sign Artwork?

Before approving tactile sign artwork, verify character height, raised depth, stroke thickness, proportions, font style, character spacing, line spacing, and border clearance against §703.2.1–.2.8.

The review should use the actual text and selected font, including the uppercase "I" and "O" reference characters. Check that the letterforms meet the applicable requirements and that the layout leaves sufficient room for compliant spacing between characters, lines, borders, and decorative elements.

Production specifications should also identify the intended raised-character construction and finished dimensions. Reviewing a drawing or sample before manufacturing helps identify dimensional problems early, but final compliance must be assessed against the applicable requirements and the finished sign.

 

Common Mistake: Confusing Character Height With Raised Depth

Wrong: Treating the height of the letter and the depth of its raised surface as the same measurement.

Correct: Character height is generally 5/8–2 inches, while raised depth must be at least 1/32 inch above the background (§703.2.1 and §703.2.5).

These measurements control different aspects of tactile lettering. A character may fall within the permitted height range but still fail the raised-depth requirement. Likewise, sufficient raised depth does not compensate for an incorrect character height, font style, stroke thickness, or spacing.

Review these dimensions independently when approving artwork and finished samples. A single visual check cannot establish that all tactile-character requirements have been met.

 

Related Products and Guides

ADA Braille Signs — Explore Braille signage information and the relationship between Braille and raised-character requirements.

ADA Room Name Signs — Review room-name sign options and consider tactile-character specifications during customization.

 

Frequently Asked Questions

Can a decorative font be used for ADA tactile lettering?

No. Tactile characters must use sans-serif lettering and must not be italic, oblique, script, highly decorative, or of other unusual forms (§703.2.3).

Which letters are used to check ADA character proportions?

The uppercase "O" and "I" are used to assess character proportions. The width of "O" must be 55%–110% of the height of "I" (§703.2.4).

Does the ADA allow smaller raised letters when visual text is provided separately?

Yes. An exception permits raised characters as small as 1/2 inch when separate raised and visual characters conveying the same information are provided (§703.2.5, Exception).

Can a sign meet the character-height requirement but still fail tactile-character requirements?

Yes. Compliance also depends on raised depth, font style, proportions, stroke thickness, character spacing, line spacing, and separation from borders and decorative elements (§703.2.1–.2.8).

Should tactile character dimensions be verified after fabrication?

Yes. The finished characters should be checked against the approved specifications because the design file alone does not establish that the manufactured sign meets the applicable dimensional requirements (§703.2.1–.2.8).

 

Official Sources

U.S. Access Board — Chapter 7: Signs — Official text of §703.2.1–.2.8.

U.S. Department of Justice — 2010 ADA Standards for Accessible Design — Complete federal accessibility standards.

2010 ADA Standards — Official PDF — Downloadable version of the Standards.