The readability of a sign is affected by a number of factors and one of those is the CAPITAL LETTER height. Obviously the larger the letters the easier it can be read from a large distance but how can you check exactly what is the optimum size.

To calculate the CAPITAL HEIGHT for your new signage, you can use a simple calculation.

At Modulex we use a Readability Factor (R) of 0.0027 as our standard value, this ensures that close to 85 % of all users will be able to read the information. The Readability Factor can be adjusted based upon the users of the space and the likeliehood of their reading ability being better or worse than this standard value.

For users with expected poor eyesight the Readability Factor should be decreased and for users who it is expected will have good quality eyesight the Readability Factor can be increased as shown in the table below.

R = 0,0015: lowest sight
R = 0,0019: lowest reading
R = 0,0027: Modulex standard
R = 0,0030: 90% sure reading
R = 0,0070: 100% sure reading

Check your existing signage to understand the Readability Value for your visitors by using this calculation.


What other factors can affect the readability of a sign?

There are, of course, other factors which also play an important role which need to be considered alongside the mathematical equations.

What angle is the sign being read from?

Is the reader likely to be walking, running, cycling or driving past the sign?

Is the sign well lit?

How stressed are the users likely to be , for example is it a hospital or a theme park?

Are weather factors likely to have an impact?


How else can you improve readability?

First, your choice of typeface is important – make sure it’s clear and simple, increasing spacing between the letters can often be a good solution especially if there is a lot of information that needs to be read from an angle.

Contrast between signage and text is also very important, but also contrast between surroundings and the signage is needed, signage that blends in are seldom a good solution.

We recommend for wayfinding information a minimum Light Reflection Value (LRV)  of 70 %. Subscribe to our news using the box below and you will get more information about Light Reflection Value.

These small tips can help you get it right first time or even to evaluate your existing signage.

But feel free to contact us for free advice or a site survey – we have the know how – just contact


  • Modulex to establish company in Dubai

    With the wish to increase its presence in the MENA region Modulex will open an office in Dubai.

    Read more>>
  • Will your signage withstand the weather?

    Will your signage withstand the weather? Be confident with our short guide.

    Read more>>
  • A new partnership serving Bavaria and Austria

    A new partnership serving Bavaria and Austria.

    Read more>>
  • NEW CPD available from Modulex

    Developed in conjunction with The BCFA

    Read more>>
  • Meet the designer: Jon Brøcker

    Launched during 2017, VIA architectural signage, designed in collaboration with International architecture firm C.F. Møller, was developed originally for the wayfinding scheme at the Aarhus University Hospital (AUH), Denmark.

    Read more>>
  • How 3d printing can play a part in identity design

    Recreating shapes and materials using 3d printing technology is an undoubtedly exciting opportunity for anyone in the creative industry.

    Read more>>
  • Need to check your text is legible?

    There are many elements that determine a successful sign scheme and one of those elements is the size of the letters. Use our easy formula to check your new and existing signs.

    Read more>>
  • Danish inspired modular architectural signage

    The VIA architectural signage system, designed in collaboration with International architecture firm C.F. Møller, is the latest line available from Danish architectural signage company Modulex.

    Read more>>
  • Can timing impact your next rebrand?

    According to research from Deloitte, 2017 is expected to see accelerated growth in mergers and acquisitions (M&A).

    Read more>>
  • Wayfinding and signage at lillebaelt academy

    Working with Henning Larsen Architects, Modulex have project managed both external and internal signage for the Lillebælt Academy, Denmark.

    Read more>>