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CAPTCHA Can Kill Your Conversion Rate

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CAPTCHA from Air New Zealand

More and more websites are using CAPTCHA to avoid spam, but they’re typically bad for your business as CAPTCHAs have major usability problems. Most visitors simply get them wrong.

Why CAPTCHAs Are Bad For Business

From the perspective of a web developer, a CAPTCHA may seem like a great solution to prevent spam. However, from a business perspective CAPTCHAs can be pure poison as they have a lot of usability problems:

  • CAPTCHAs are difficult to decipher. This is what makes them technically good, however, obscuring text and asking your visitors to repeat that text will hurt your conversion rate badly. And let’s face it, even people working with websites daily read a CAPTCHA wrong every now and then.
  • CAPTCHAs carry no meaning. Most CAPTCHAs are just a random combination of letters and numbers, leaving your visitors with little clues as to whether or not they got it right before submitting the form. Additionally, even if they do read it correctly, because it have to be an exact match there’s also the risk of your visitor simply mistyping it.
  • Your visitors don’t understand what CAPTCHAs are for. Why are you forcing them to go through an eye exam and spelling test? Some will be annoyed that you’re treating them like a 3rd grader, others may even feel insulted.
  • People with lowered vision can’t read your CAPTCHA. This makes it near impossible for them to read the already mangled characters of your CAPTCHA.

Some visitors will leave you site immediately when they see your CAPTCHA simply because they don’t understand what it’s for (problem 3). The visitors that do understand it, but are either unable to see it (problem 4), can’t read it (1) or mistyped it (2), will get so frustrated that there’s a good chance they will leave your site too.

Are you willing to take this chance? My suggestion is to set up a split test where you remove the CAPTCHA and then compare the value of the extra conversions against the extra hassle of deleting some additional spam.

If You Still Need A CAPTCHA

If you absolutely, positively must implement a CAPTCHA on your site, then at least consider these 6 10 ways of making you captcha more user friendly:

  1. Use a huge CAPTCHA so your visitors won’t have to go scrambling for their reading glasses.
  2. Make the CAPTCHA ask for real words or sentences so your visitors can deduce the characters that are really difficult to read from the characters that are easier to read.
  3. Reload just the CAPTCHA if your visitor gets it wrong so he don’t have to fill in all the other form fields on the page again.
  4. Give your visitors an option to get a new CAPTCHA image so they have the possibility to get another one if the current is too difficult.
  5. Tell your visitors you’ve implemented the CAPTCHA to prevent spam. This way you at least explain to them why they need to go through all that hassle. Some visitors may even sympathize with you, as they themselves have trouble with spam.
  6. Only ask your visitors to type your CAPTCHA once through the entire session. E.g. if you have a service for getting price quotes, don’t show a CAPTCHA at every request, only during the first request.

What’s your opinion on CAPTCHAs?

Ideas Added by Commenters:

7) Use a simpler CAPTCHA (added by Jeff Ogden)
For instance, I’ve seen "What is the sum of 7 plus 5? Or give me a few words and tell me type the third word. Those are much easier for humans and damned near impossible for SPAM.

8) Accept minor errors (added by George)
Use a captcha which allows the user to guess the word, a minor (one character wrong or so) is accepted.

9) Enhance accessibility with audio options (added by George)
A audio button for visually impaired users.

10) Support a greater cause (added by George)
Make use of the 200+ million captchas solved by humans every day-
Recaptcha (http://www.google.com/recaptcha) uses words scanned from books, the words entered by humans are then put together and voilá, the books have been digitalized.

Robert November 4, 2009 Reply to this comment

Great post!

Anyways: I don’t understand is how for example a lot of wordpress-sites can easily live without a captcha. Are they doing something with the email to prevent spam? Something else? What are you using(own blog-software I guess)?

Jamie, Baymard Institute November 5, 2009 Reply to this comment

Thanks Robert,

WordPress blogs have Akismet installed by default I believe. You may need an API-key but it is free.

This blog is custom-built in Ruby on Rails (so we can easily implement various kinds of tracking) and we have a very simple system that just looks at any new comment and if it has more than two links in it, the comment is marked for review and one of us then have to manually approve or delete it.

johnson November 10, 2009 Reply to this comment

great post, hate those Captchas

CHS March 31, 2010 Reply to this comment

Do you know what % of websites are abandoned due to bad captcha?

Christian, Baymard Institute April 2, 2010 Reply to this comment

@CHS
No I don’t have such statistic. CAPTCHA abandon rates are very individual to each site so any example statistics wouldn’t have much use to anyone, but try to do an A/B split test, with and without the CAPTCHA, and see which one works best. I’m sure you’ll reach the same conclusion we did.

Jeff Ogden February 5, 2011 Reply to this comment

Great post. I’d love to use it at Fearless Competitor, if you don’t mind. I’ll link back here.

Jeff Ogden, the Fearless Competitor
Find New Customers
@fearlesscomp

Christian, Baymard Institute February 13, 2011 Reply to this comment

Glad you liked it. Feel free to do so as long as you attribute.

Jeff Ogden February 5, 2011 Reply to this comment

Here’s one I’d like to add:

Use a simpler CAPTCHA. For instance, I’ve seen "What is the sum of 7 plus 5? Or give me a few words and tell me type the third word. Those are much easier for humans and damned near impossible for SPAM.

Christian, Baymard Institute February 13, 2011 Reply to this comment

Great tip Jeff, thanks for sharing.

Alex February 6, 2011 Reply to this comment

On viable alternative that deals with a few of these issues, is reCaptcha (http://www.google.com/recaptcha).

George February 9, 2011 Reply to this comment

If you still need a CAPTCHA tip 8:

Use a captcha which allows the user to guess the word, a minor (one character wrong or so) is accepted.

Tip 9:
Accessibility -
A audio button for visually impaired users

Tip 10
Make use of the 200+ million captchas solved by humans every day-
Recaptcha (http://www.google.com/recaptcha) uses words scanned from books, the words entered by humans are then put together and voilá, the books have been digitalized.

Christian, Baymard Institute February 13, 2011 Reply to this comment

All great tips, added them all. Thank you George.

rajesh mergu February 18, 2011 Reply to this comment

Good post, I like some points but i would go for using catcha and thanks for adding what if we still want to use catcha, good things to consider, cheers, raj

jesse chang February 21, 2011 Reply to this comment

See solve media’s solution at http://www.solvemedia.com where they use real words and make it easier for users

Anthony Goodley February 21, 2011 Reply to this comment

I made my own Ajax CAPTCHA http://mywebs.biz/Captcha/ . It implements everything the author suggests, and then some. Like the “Zoom” buttons. I would appreciate comments, suggestions and feedback as I’m considering making it available for downloading.

My suggestion would be that all CAPTCHA’s should have JavaScript zoom buttons. Yet I have never seen one, besides my own, that does have this.

I would like to add user suggestion #8 to mine but that isn’t possible since the answer is one way encrypted. It must perfectly match or fail. #9 is on TODO list.

NOTE that this form is disabled and is only for evaluating the CAPTCHA.

Thanks for the helpful article, it confirms I’m headed in the right direction here.

Thanatopsis November 11, 2011 Reply to this comment

What is this “conversion rate” you keep talking about? I don’t see how this has anything to do with converting anything.

April 23, 2012 Reply to this comment

On number 3 of the top list, you misspelled “feel” as “fell”.

Julia October 2, 2013 Reply to this comment

better don’t use Captcha at all. The cutest that it could be – it’s still annoying and insecure. Robots can read it, and it doesn’t stop human spammers. I suggest using Keypic, you’ll feel the difference. Users don’t do anything, all is done by the system itself.

Klaus Martin Meyer July 12, 2014 Reply to this comment

Use a “honeypot” — an invisible field (for example “time zone”) that only SPAM-Bots will find and get rid of CPATCHAs all together.

Klaus Martin Meyer July 12, 2014 Reply to this comment

Use a “honeypot” — an invisible field (for example “time zone”) that only SPAM-bots will find and get rid of CAPTCHAs all together.

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