This is something I've always wanted to ask because it's really frustrating for me.

If you use Paypal, you will see that when you try to send money, the Amount input requires to enter the cents or decimals. Look at the picture below

Enter image description here

In this real case, I had to send $160. On most apps, you enter $160. On Paypal you have to enter 16000 or you send $1.60. I've had this error once or twice, and now I'm very careful to double and triple check because I sometimes enter an extra 0.

I've never seen this before (although I've started to see this AFTER Paypal started to do it ). Based on the principles of intentionality in UX, if I wanted to add decimals, I would use floating point and then add decimals. So I'm wondering why they would do something so confusing and if there is some sort of rationale that I'm not aware of

Also, from a Universal UX theory perspective, this is a fail. Paypal knows my country and my language. So they should know that floating point has a whole different meaning for me (we use commas for decimals). Therefore, it's an even bigger cognitive load. This is a small consideration in the grand scheme of things, but pretty striking when you consider such an important company.

Anyway, is there some kind of explanation from Paypal or a rationale I'm not getting (maybe because of cross-cultural barriers?)? Or is it just an anti-pattern?

  • 3
    This is very common in any POS (Point of sale) system, and many ATMs. I don't know how far back it goes, but even in the early 1990's this behaviour was standard on most terminals. Edit: There's a thread I just found discussing it further: ux.stackexchange.com/questions/121621/… Commented Jun 4, 2021 at 0:59
  • I think they are simply saving you time typing the decimal point, that's all.
    – Steve
    Commented Jun 11, 2021 at 15:34
  • I think the comma for decimal is sort of a fail, but other than that I think this behavior (not sending enough money) is preferable to the opposite behavior in which you send too much money. At the very least, it basically makes it impossible for them to change this behavior safely. In the US at least, there are a few other banking apps that do the same thing, so that may be why they decided to do this initially.
    – jeffkmeng
    Commented Aug 1, 2021 at 7:06

1 Answer 1


One thing that comes to my mind (note, that this is pure speculation) is imagine this:

  1. There are people who are used to this "very common in any POS system" (as mentioned in one of your comments) pattern and expect it in this form;

  2. There are people who expect it to work as you and me would - entering the whole numbers first;

Both of those groups of users are using the same form.

Now consider the cost of mistake for both of those groups:

  • if somebody from group two enters "160" and presses "send" without checking, if it worked as you wanted, they'd send more than expected by mistake (160 USD instead of expected 1.60 USD). The cost of that mistake is potentially pretty huge - they'd have to manage returns and talk to the support, or even lose the money.
  • For the group one - it's the other way around: if they enter "160", expecting to send 160 USD, and press "send", in current form they potentially would only send 1.60 USD instead of expected 160 USD, which is less than expected, so the cost of mistake is way smaller. They'd probably just learn from their mistake and send the missing 158.40 USD amount with next transaction. Not as big of a deal as for group two.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.