Is my sign readable? Check before you print or publish it.
Upload your design, pick the screen size and distance, and see what your customer will actually see: a simulation from that distance, the contrast between colours and the minimum height your letters need. Free, no sign-up, and the image is never uploaded anywhere.
How to read the result
The simulated view
We reduce the design to the detail a human eye resolves at that distance (1 minute of arc with normal sight, 2 with reduced sight). Whatever blurs there blurs in the shop too.
Letter height
What matters is the angle a letter covers in the eye. ISO 9241-303 asks for at least 16 minutes of arc and recommends 20–22; to read at a glance while walking past, go bigger.
Contrast
We use the WCAG contrast formula. 4.5:1 is a sensible minimum for text; on signage, with glare and ambient light, the closer to 7:1 the better.
Frequently asked questions
Do you upload my image to a server?
No. All the maths runs in your browser in JavaScript. The image is not sent or stored, and it is gone when you close the page.
What letter size do I need at 5 metres?
At least about 23 mm of capital height, and about 32 mm to read comfortably. On a 55" Full HD screen that is roughly 37 and 51 pixels in your design.
Does it work for printed signs?
Yes: choose the screen size closest to your sign. The minimum height in millimetres and the contrast apply to paper just as much as to screens.
What if it is not readable?
Less text and bigger, more contrast between text and background, and plain typefaces. If you show the same content on several screens, RDS lets you change it on all of them at once.
Already made one? Recover your screens
Type the email you used and we will send you the links to all your screens again.
Publishing your designs on several screens?
With RDS you upload the design once and send it to all your screens, on a schedule and without USB sticks. 30-day free trial, no card.
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