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Calcimator

Signage Letter Height Calculator

Letter height from viewing distance and speed.

Inputs

Results

Min letter height (in)

2

Min letter height (cm)5.08
Stroke width (in)0.33
Max read distance (ft)100
Reading time (sec)999
Max words on sign20
How to Use This Calculator
  1. Enter Viewing distance (ft), Viewer speed (mph), and Contrast level (1–3).
  2. Set Illuminated (0/1) and Font style (1–2).
  3. Review the Min letter height (in) result.
  4. Use Min letter height (cm) and Stroke width (in) to inform your decision.

How the result changes with Viewing distance (ft)

Viewing distance (ft)Min letter height (in)
50110.02
1,75135.02
3,25065
4,50090

What each input means

Viewing distance (ft)
Distance from which the sign must be readable, in feet.
Viewer speed (mph)
Speed of the viewer (0 = pedestrian, 25 = city driving, 65 = highway).
Contrast level (1–3)
Letter/background contrast: 1 = Low, 2 = Medium, 3 = High (black on white).
Illuminated (0/1)
Is the sign externally or internally illuminated? 0 = No, 1 = Yes.
Font style (1–2)
1 = Serif (needs larger letters), 2 = Sans-serif (better distance legibility).

What each result means

Min letter height (in)
Minimum recommended capital letter height in inches for legibility.
Min letter height (cm)
Same measurement converted to centimeters.
Stroke width (in)
Recommended stroke width (1/6 of letter height) for optimal legibility.
Max read distance (ft)
Maximum distance at which these letters are readable for a stationary viewer.
Reading time (sec)
Seconds the viewer has to read the sign at their speed (999 = stationary).
Max words on sign
Maximum recommended word count given available reading time.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Viewing distance (ft) = 100, Viewer speed (mph) = 0, Contrast level (1–3) = 3, Illuminated (0/1) = 0 = 5 input(s) provided
  2. Calculate Min letter height
    Min letter height = viewingDistanceFt / 50
    2 = 2
  3. Calculate Min letter height
    Min letter height = letterHeightMm / 10
    5.08 = 5.08
  4. Calculate Stroke width
    Stroke width = letterHeightIn / 6
    0.33 = 0.33

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