Nielsen’s ten usability heuristics, with checkout examples

A checkout is a short journey with a lot riding on it. A customer who has already chosen a product can still give up because a button did nothing, an error made no sense or the delivery cost appeared at the last step. Most of these problems are predictable, and a simple set of rules of thumb will catch many of them before a single customer meets them.

Jakob Nielsen’s ten usability heuristics are the best-known set. Below, each one is explained in plain words and then applied to an online checkout. The checkout examples are illustrations written for this article, not case studies of real shops.

Where the heuristics come from

Nielsen developed the heuristics with Rolf Molich in 1990 and refined them in 1994, based on a factor analysis of 249 usability problems. Nielsen Norman Group describes them as broad rules of thumb rather than specific usability guidelines. A 2020 update added explanations and examples and lightly refined the wording, but the ten heuristics themselves have not changed since 1994. The names below follow Nielsen Norman Group’s current wording.

Heuristics 1 to 3: keep people oriented

1. Visibility of system status

Keep people informed about what is happening, through timely feedback.

Checkout example (illustration): show a step indicator such as “Step 2 of 3: Delivery”. When the customer presses Pay, change the button to “Processing payment” and disable it. Without that feedback, some people press again and wonder whether they have been charged twice.

2. Match between the system and the real world

Use words and ideas that are familiar to the user, follow real-world conventions and put information in a natural, logical order.

Checkout example (illustration): a UK shop should ask for a “Postcode”, not a “ZIP” or “Postal routing code”. Label the final figure “Total to pay”, show the currency symbol and list items in the order people think about them: products, delivery, total.

3. User control and freedom

People make mistakes and change their minds. Give them a clearly marked way out of an unwanted action, without a long process.

Checkout example (illustration): let the customer change a quantity or remove an item from the order summary without leaving checkout. Make the browser Back button return to the previous step and keep what they typed. Nielsen Norman Group specifically warns against disabling Back and recommends warning people before any action that would lose their work.

Heuristics 4 to 6: prevent mistakes before they happen

4. Consistency and standards

Words, situations and actions should mean the same thing throughout, and the design should follow platform and industry conventions.

Checkout example (illustration): pick one word, “basket” or “bag”, and use it everywhere. Keep card fields in the order people expect: card number, expiry date, security code. Give the main action on every step the same button style and position.

5. Error prevention

Better than a good error message is a design that stops the error happening. Remove error-prone conditions, or ask for confirmation before people commit.

Checkout example (illustration): offer a postcode lookup so customers pick their address instead of typing it. Grey out delivery dates that are not available. Show a full order review, with address and delivery option, before the final Pay button.

6. Recognition rather than recall

Make options and information visible so people do not have to remember them from one screen to the next.

Checkout example (illustration): keep a compact order summary visible on every step, including the discount already applied. For a saved card, show the card type and last four digits so the customer recognises which card they are about to use.

Heuristics 7 and 8: speed and focus

7. Flexibility and efficiency of use

Offer shortcuts that speed up experienced users while staying out of the way of newcomers.

Checkout example (illustration): returning customers can sign in and use saved details, while first-time buyers can check out as a guest. Mark up address fields so the browser’s autofill works. Offer express wallet buttons alongside the standard card form, not instead of it.

8. Aesthetic and minimalist design

Every extra piece of information competes with the information that matters. Remove what is irrelevant or rarely needed.

Checkout example (illustration): hide the main site navigation and promotional banners during checkout. Put optional fields such as “Company name” behind a small “Add company details” link. Keep the page about one thing: finishing the order.

Heuristics 9 and 10: when things go wrong

9. Help users recognize, diagnose, and recover from errors

Error messages should use plain language, say exactly what the problem is and suggest a way to fix it. (The heuristic’s name uses American spelling, as Nielsen Norman Group publishes it.)

Checkout example (illustration): “Error 402: invalid input” helps nobody. “The card number looks one digit short. Please check it” sits next to the field and keeps everything else the customer typed. Nielsen Norman Group’s error message guidance adds that messages should appear close to the problem, should not rely on colour alone, and should avoid words such as “invalid” or “illegal” that blame the user.

10. Help and documentation

The best design needs no explanation. When help is needed, it should be easy to find, focused on the task and short.

Checkout example (illustration): put a small “What is this?” link beside the card security code field. Keep delivery and returns information one click away without leaving checkout, and show a phone number or chat option for anyone stuck.

Running a quick heuristic review of your checkout

A heuristic evaluation is the method these rules were made for. Nielsen Norman Group’s guidance runs in three stages:

1. Prepare. Choose your heuristics (these ten are the usual choice), narrow the scope to one task, such as buying a single product as a guest on a phone, and agree how you will record problems.
2. Evaluate on your own. Each reviewer walks through the task once to learn it, then again to note anything that breaks a heuristic. The guidance suggests timeboxing this to about one to two hours, and reviewers should not see each other’s notes until they finish.
3. Consolidate. Group similar issues, discuss disagreements and decide which problems hurt customers and the business most.

Nielsen Norman Group recommends three to five people evaluate the same interface independently, because even experienced reviewers miss problems that others spot. For a small business, that could be you, a colleague and a friend who has never used your site.

What the heuristics will not tell you

Heuristics are a cheap first pass. Nielsen Norman Group states plainly that heuristic evaluations cannot replace user research. The findings also depend heavily on the reviewers’ experience and are judgements rather than measured data. Use a review to find the likely problems, fix the obvious ones, and then watch a few real customers try to buy something. The places where they hesitate will tell you which of the ten heuristics your checkout breaks most often.