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Chapter 6

Let people make mistakes when entering numbers

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#Common number entry errors

People make form errors like:

  • entering sensitive information in the wrong field 

  • typing letters instead of numbers

  • entering the wrong date and time 

  • paying the wrong amount of money 

When paying for something online, most forms capture card details out of order, so errors occur when people enter information using a credit card in the wrong form fields. 

A report on checkout UX showed that:

  • people are likely to enter information in the order they appear printed on the physical card

  • a third of users typed their full credit card number in the cardholder name field because it was the first form field

  • a third of sites don’t match the credit card field sequence to the physical card sequence

  • people make the most errors entering the long credit card number, which is usually 16 numbers long 

  • checking a 16 digit number for errors is difficult

  • half of the sites incorrectly format the expiry date field

At a minimum, you should match the credit card field sequence to the physical card, usually the card number, expiry date, name and security code.

Nowadays, most browsers have an autofill feature. Autocomplete is simple, clear and built into HTML5, so you should add it to your form.

#Don’t time people out 

Authentication apps and countdown timers help keep accounts and passwords secure, but they could harm people who need help with numbers. 

Authentication apps give people seconds to remember a number. Some people need more time to remember, write down, or input the number, so they are often timed out and sometimes locked out of accounts.

Some neurodivergent people experience time blindness, which means they can’t accurately assess how long a task will take or tell how much time has passed since starting something.

And most dyscalculics struggle to tell the time

Bottom line, authentication is inaccessible if you:

  • have disabilities that make it hard to switch between applications and fill out forms

  • have autism, ADHD and dyscalculia and experience time blindness

  • have poor network or wi-fi access

People will choose to use a service unsafely to get around barriers

#Write clear error messages 

Error messages tell people why they can’t move forward. Error messages should be: 

  • specific

  • informative 

  • easy to read and understand

  • helpful 

People who struggle with numbers might make errors when:

  • paying for something

  • entering an address

  • planning a journey 

  • arranging an appointment 

  • picking a date or time 

  • logging in 

You can help people recover from errors calmly and kindly. Check out: