The Complete Guide to Readable Code: 11 Principles

When you were learning to read as a small child, your parents and teachers probably began by introducing you to simple books. As you got older and went from gawking at fairy tales to putting your own words on paper, it’s likely that your ability to convey your thoughts in writing also became more precise. 

When you embarked on your journey as a developer, it may not have occurred to you that your first coding experiences would draw upon knowledge from some of your earliest communication skills. While many great writers aim to keep their documents clear and concise, coding is no different. Code is simply writing in various languages that tells a computer what to do. 

Let’s take a look at readable code, why it matters, and 11 principles that will help you create code that is short, sweet, and to the point, today. 

• What is readable code?
• Why does readable code matter?
• 11 principles of readable code

What is readable code?

Readable code is code that clearly communicates its intent to the reader. While it’s easier said than done and often a challenge for inexperienced developers, creating readable code is as important as solving any software problem—this is why it’s often one of the first techniques a developer learns on the job. Code readability has two key requirements: The first is that the code must produce the expected result, and the second is that the code should be easy for other developers to read. Messy code is like a messy coffee cup; if it’s not clean, others won’t choose to clean it themselves simply so they’re able to use it!

Why does readable code matter?

Code readability is fundamental. Think about it: how can you fix something that you struggle to read? Poorly written code can cause a variety of issues. For example, a developer who writes detailed code at the beginning of a system development process may realize a year later that they don’t understand their own code and will be left having to re-teach themselves their own system’s technicalities. Alternatively, when code is easy to read, it’s always easy to understand, debug, maintain, and extend! 

11 principles of readable code

• Structure your code
• Test your code
• Ask a coworker to explain the code to you
• Simplify your code
• Align your code
• Stick to a maximum of 80 characters per line
• Name the code based on variables that explain themselves
• Ensure it has a single responsibility
• Explain the why and code the what
• Follow a style guide 
• Use plenty of documentation

1Structure your code

Well-structured code requires an understanding of design patterns, proper thinking, and plenty of experience. When code is well structured, it has a clear purpose. All classes and methods should be clear and easily understood. Ask yourself: is the codebase easy to navigate? Remember that formatting should be consistent across classes!

2Test your code

Complete manual and automated tests to ensure your code is readable. When you proactively test your code, it can be modified quickly and without fear of breaking things. Restructuring existing code is also risky without the necessary testing. However, with tests, you won’t need to worry about making large refactors in the future. If you’re a new developer, get into the habit of writing unit tests for your code to make sure it works correctly, and to help detect and protect against future bugs. 

3Ask a coworker to explain the code to you

Ask your developer teammates to read your code and give you feedback. Encourage your colleagues to ask questions if something doesn’t make sense. If your code is readable, your feedback givers should ask little to no clarifying questions. At the end of the feedback session, ask your teammates if they understood the intent of what you wrote and have them explain it back to you. Don’t get discouraged if there’s any misunderstanding. Remember that questions will only lead to opportunities to make your code more readable. 

4Simplify your code

The great painter Leonardo da Vinci once said that “simplicity is the ultimate sophistication.” Coding is a creative craft that is no different! Aim to make your code elegant—simple to read, orderly, and easy to understand. Don’t try to over-complicate things with elaborate tricks. Keep your classes a reasonable size and most of your functions short. 

5Align your code

It’s simple: aligning your code looks better! Aligning your code helps you present your hard work beautifully and makes it much easier to read. It may seem silly, but the aesthetics of code are often as important as the code itself. If your code isn’t aligned, you’ll need to put in extra effort when refactoring as well. Many developers better format their code by keeping it aligned to the left. Since we read from left to right, more of the code will be visible when formatted this way, and you may even be able to avoid the need to scroll the code editor when reading through your code horizontally. 

6Stick to a maximum of 80 characters per line

When you’re reading a newspaper, articles are arranged in many columns because it’s easier to read. Your code is no different. Limit your line length to around 80 characters. If your code is too wide, it may be difficult to look at on a small device, it will be difficult to compare changes to another file side by side, and it will definitely be difficult to present to your manager and teammates, or at meetings, conferences, and events. 

7Name the code based on variables that explain themselves

A big aspect of making your code easy to read lies in the name you choose. The name of your code should clearly describe its purpose. Name your variables, function, and methods by what they do or what they are. For example, if your variable gets something, include “get” in its name. If you can’t name the method or function, the function may be too complicated. If you can, go back and break complicated functions into smaller functions to simplify.

8Ensure it has a single responsibility

The single responsibility principle means that every building block does one thing and one thing only. All building blocks, including methods, variables, and classes, follow this rule so it’s easy for the person reading the code to understand their responsibility. When your code follows this principle, it’s easily maintainable and scalable. When concerns are separated, you can focus on what features you actually want to work on rather than having to navigate interconnected lines of code. 

9Explain the why and code the what

Comments shouldn’t tell us what we already know. They should tell us why things are happening. You should be able to write no more than a one-line comment explaining what the code is doing. If you can’t, rewrite the code until it is more readable. If the code is obvious, you can avoid comments altogether. The code should be able to speak for itself in many cases. 

10Follow a style guide 

Follow your language’s style guide if there is one! House rules keep everyone on the same page. Companies like Google swear by style guides to keep tens of thousands of programmers consistent. Style guides are composed of two parts: rules and guidance. Rules are mandated with few exceptions, and some companies enforce them throughout the entire organization. Guidance simply refers to recommended strategies and practices that allow for more leeway. When you follow a style guide, you may be better able to focus on what’s getting done rather than how it’s coded. 

11Use plenty of documentation

As you become a pro at writing readable code, document your progress. This way, you’ll always have an extensive knowledge base at your fingertips! Use Fellow to build your collaborative meeting agendas, record decisions, and keep each other accountable! The next time you have a check-in with your manager or have a colleague proofread your code, you can document the conversation, jot down feedback and key takeaways, organize your ideas, and assign action items based on what needs to get done. You shouldn’t feel stuck in coding or in your career! Through great habits and fostered accountability, you can stay productive and engaged as you strive to write readable code. 

Parting advice 

Good writing is clear thinking made visible. Coding is similar. When code is too complex, it’s hard to test and can lose all of its meaning for other developers. By keeping things tight and consistent, you can focus on what the code actually does rather than explaining it. 

If you’re a developer by trade, you may not have loved language courses in school. Writers swear by a few key rules: stick to simple sentences and shorter words, avoid jargon, and strive to express, not impress. Next time you’re writing a line of code, think about the rules of writing! It goes without saying that coding is today’s very own language of creativity.

Use our 11 principles to create readable code today that speaks for itself!