It is twenty past nine in the evening. Someone finally sits down, remembers the car is due for its MOT next month, and finds your site on their phone. Name, mobile number, registration. They press Send.

The page jumps to the top and a small red line appears somewhere: Invalid input. They scroll. Which field? No idea. They try again, notice their phone number has been wiped, and close the tab. Tomorrow they ring the garage two streets over.

You never hear about any of this. That is the trouble with form problems: no complaint, no bounce message in your inbox, no angry review. Just a booking that quietly never happened.

Three places a form loses people

The label disappears. Plenty of forms put the field name only as grey text inside the box. The moment someone starts typing, it is gone. On a small screen, with a child asking something and the television on, it takes about ten seconds to forget whether that box wanted your mobile or your landline. Put the label above the field and leave it there.

The error does not say what to do. "Invalid input" is not an instruction. It is a door closing without telling you where the key is.

Correcting it is punished. The form clears itself, or throws you back to the top of the page while the error sits at the bottom. People will retype everything once. They will not retype it twice.

Write the error the way you would say it out loud

If someone at your counter wrote down a number with a digit missing, you would not say "invalid input". You would say: "I think there's a digit missing — does it start 07?" Put that in your form.

Three things make the difference. Name the field ("Your phone number"), say what you expect ("eleven digits, no spaces"), and keep whatever they already typed. And never rely on a red border alone: it is invisible to someone who does not distinguish colours well, and nearly invisible to anyone outdoors in daylight. Put the message in words, right next to the field that is wrong.

The cheapest error message is the one you never need. Every field you delete is a field that cannot go wrong. Look honestly at your form: do you really use that postal address on a first enquiry?

The twenty-minute test you can run yourself

Take your phone, walk outside, and fill in your own form as if you were a customer. Not on your big screen indoors. Outside, in daylight, one-handed.

Then make mistakes on purpose. Leave the email address blank. Type a phone number with a letter in it. Submit half a form. After each one, ask a single question: do I now know exactly what to fix? If the answer is no, you have found a job.

Finally, do the same round on your laptop without touching the mouse. Tab key and Enter only. Can you get through the whole form, and can you always see where you are? People with limited hand movement navigate this way, and so does anyone using a screen reader — or anyone whose trackpad has just died. If you get stuck, so do they.

Contrast and text size: the boring settings that do the most work

Light grey text on white looks calm in a design and is unreadable on a phone in the sun. Keep dark text on a light background; the common standard is a contrast ratio of 4.5:1 for normal text, and free online checkers will tell you in two seconds whether you clear it.

Set body text on mobile to at least 16 pixels. It reads better, and it also stops an iPhone zooming in the moment someone taps a field. Make buttons and checkboxes big enough for a thumb, roughly 44 by 44 pixels. And put your phone number and opening hours on the page as text, not inside an image: text can be enlarged, copied and read aloud.

The legal part, briefly

Since June 2025 the European Accessibility Act has applied to many digital services sold to consumers: online shops, banking, transport tickets, e-books. Small service providers with fewer than ten staff are largely out of scope, and enforcement varies by country. So for most one-van businesses this is not an urgent duty. But the requirements are precisely the things above, and doing them calmly now is cheaper than doing them later against a deadline.

What to do this week

  • Fill in your own contact or booking form on your phone, outdoors, and get one field wrong on purpose. Write down what happens.
  • Rewrite every error message so it names the field and says what you expect. That is writing, not programming.
  • Delete one field you never actually use, and check that body text on mobile is at least 16 pixels.

If you cannot find where a particular setting lives, this is usually an hour or two of work — at ITSysPro we do it fairly often as a standalone job. Either way, start with the test outdoors; it usually tells you everything you need to know. Happy to talk it through if you would like a second pair of eyes.