I'm working on a project that includes an in-browser Chat feature. We're looking for ways to improve the UX.


Today, our online chat UI offers a textareathat allows customers to type an average of 400 characters into a message. This results in extremely long messages where the users thought often gets lost.


In doing some research, it's been suggested that a limited input area might encourage more users to complete their thought in fewer words. This results in clearer messages and quicker responses.

Is there any evidence that shows that simply making an input field shorter/smaller encourages users to complete their thoughts more efficiently?

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  • Have you considered doing sort of an A/B test where you'd record the input height and the corresponding message length and then just compute the correlation? Commented Jan 31, 2015 at 11:37
  • That's always my first suggestion. However, I need some sort of evidence that suggests a different outcome before we can move to A/B testing. (yes, I know this sounds backwards) Commented Jan 31, 2015 at 14:50
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    Wouldn't it be good if by default it was 1 line and when the user touched/clicked inside the text box area it would extend up into 2 lines?
    – Vader
    Commented Jan 31, 2015 at 18:34
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    The existence and success of Twitter is the proof you seek in and of itself. Commented Jan 31, 2015 at 19:25
  • @Inquisitive - This is true...However, I'm looking for evidence of the same success in a Chat context rather than a publishing tool. Commented Jan 31, 2015 at 23:20

5 Answers 5


I'd say yes, absolutely.

When presented with a larger box, the visual implication is that the text ought to be longer and well thought-out.

Take this site we're on now as an example. We're meant to type out researched, thoughtful replies that may very well be several paragraphs long. The initial box is sized to fit several paragraphs to encourage this. There's even a little drag button to lengthen the box you're typing in, in case the reply gets a bit lengthy and you need a bit of breathing room.


For sure affect UX starting with a very simple reason:

Optimizing space without usability drawbacks

The size of the screen is limited , so when you give some space to a section you take it from another.

If you set a 2 lines input, you may lose unnecessarily 1 line of space for the history for example.
If you set a fixed 1 line input when users write 2 lines, the first get hidden, which is REALLY ANNOYING.

The standard solution is just to set a dynamic 1 line input, so the input space gets bigger ONLY when it's need, and when it's not the free space can be used for anything else. Facebook implements this:

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  • This isn't what the question is about. The question is about whether or not the size of the input area influences how concise people are with what they type. It is not about space optimization.
    – Bill Dagg
    Commented Mar 5, 2015 at 18:00

I am not aware of evidence that smaller input fields will make users type less.

A good user experience should meet the user's needs, not try to change their behavior to meet system needs. So if people are using your system and feeling lost while writing their messages, you should accommodate for that. People will want the system to bend to their will, not the other way around.

I am curious why it would be valuable to attempt to change user behavior to writing shorter messages?

  • Skype, iMessages, Facebook Chat, g+ chat, and many other chat applications we looked at seem to be moving to 1-line inputs. I would imagine this is to jump on the Twitter bandwagon to encourage users to complete their thoughts with shorter messages. While the user might want to type more, they'd realize that their questions are getting answered quicker and more accurately which in theory would be a better UX, right? Commented Jan 31, 2015 at 14:46
  • A lot of applications start with one line, but if the user types a message that needs to go to a second line, the text field will grow vertically. Check out google hangouts on your mobile phone, for example. (I also just saw that rewobs wrote something similar below.) I think this is a good implementation because you're not trying to change user behavior, just accommodating for it if they need more space. Commented Jan 31, 2015 at 23:18
  • I'm aware of this feature on mobile. Nearly all mobile apps with inputs use this pattern. We've had challenges implementing this on desktop browsers. Commented Jan 31, 2015 at 23:47
  • Are the challenges related to tech or usability? Also, is your original post asking within the context of desktop? If you're designing this for desktop then users will have a keyboard, which means it is easy for them to type more and they may in fact want to. I guess I don't understand why the goal is to encourage the user to write shorter responses-- is that part of your chat's "gimmick" (not sure of the right word to use) like twitter? I still think that on desktop, starting with one line is fine and then you can expand it as the user writes more. Commented Feb 2, 2015 at 17:01
  • UX design is about facilitating some interaction between the user and some other agent. It absolutely should not ignore the needs of the other agent in favor of the user! If both parties get what they need out of an interaction, then it can be said to have been successful. Often this means guiding a user to behave in a way that helps the system or other agent get what they need. E.g., required form fields. It would be easier on the user if they could just fill out whichever fields they wanted and then submit, but the other agent needs certain pieces of information to perform effectively.
    – sintax
    Commented Aug 22, 2019 at 18:51

Yes, the design of any type of input is essentially an affordance on how the element ought to be used.


Affordances are an object’s properties that show the possible actions users can take with it, thereby suggesting how they may interact with that object. For instance, a button can look as if it needs to be turned or pushed. The characteristics of the button which make it look “turnable” or “pushable” together form its affordances.

When designing forms and inputs it is important to keep in mind the length of inputs for the context. E.G. Short inputs for post/zip codes. This provides users with some feedforward on how to fill the form properly.


I would say you are actually using 2 separate generic widgets. The TextBox and the TextArea and they are used for different purposes.

Rather than thinking on how the User would write messages based off of your widgets, work backwards and think what kind of messages do you think the user will type into the input.

Then suitably design the widget to assist the user in typing those inputs. Case in point: You always see example 1 when you ask for a user's name. But you always see example 2 when you ask for a user's Address, A "Details" field or a "Notes" field etc.

I see from your examples that you are building some sort of messaging app. I would go with Option 2, as as to not put an undue pressure on our User to limit what they have to say. An exception to this would be WhatsApp which uses example one, but has the return icon (the symbol for enter), very prominently displayed so users know they can write multiline text.

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    The problem we're trying to solve is the lengthy messages users type today. Rather than saying: "Hey there! It's a really nice day out here in Atlanta. I had eggs for breakfast with a side of bacon....it was really tasty. I went to turn on my TV afterwards, and the screen was all fuzzy! How much would it cost for me to buy a new blender?" We want to encourage simpler messages like: "How much does a new blender cost?" Commented Jan 31, 2015 at 14:55

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