The :nth-child pseudo-class is one of the most powerful tools in a web developer's arsenal, yet its mathematical nature can be a hurdle. Whether you are creating zebra-striped tables, complex staggered grids, or highlighting specific data ranges, understanding the logic behind An + B is key to writing clean, maintainable CSS.

This interactive playground takes the guesswork out of the equation. Adjust the sliders, experiment with advanced ranges, and see exactly how your selectors behave in real-time. Once you've perfected your pattern, simply copy the code and drop it into your project.

If this site has been useful, we’d love your support! Consider buying us a coffee to keep things going strong!

If this site has been useful, we’d love your support! Consider buying us a coffee to keep things going strong!

About CSS nth Tester / Generator

This interactive CSS :nth-child() tester is designed to help you see how CSS selectors work — not just read about them.

Instead of guessing which elements will be selected, you can visually explore how different formulas behave in real time. Adjust the values, switch between grid and list views, or try built-in presets to instantly understand how selectors like 2n + 1, -n + 3, or custom ranges actually work.

Whether you’re learning CSS for the first time or brushing up on advanced selector logic, this tool makes experimentation fast, visual, and intuitive.

What you can do

• 🔢 Test any :nth-child() formula using live sliders
• 🎯 Explore presets for common patterns like odd, even, ranges, and offsets
• 🔍 See exactly which items are selected in real time
• 🧠 Understand the math behind the selector with clear, human-readable explanations
• 🔁 Switch between list and grid views to see how structure affects selection
• 📋 Copy ready-to-use CSS for your projects

Why this exists

CSS selectors can feel unintuitive — especially when negative values or ranges are involved. This tool removes the guesswork by turning abstract formulas into something you can see, tweak, and understand instantly.

It’s built to be:

• beginner-friendly
• accurate to the CSS spec
• useful for real-world layouts

Who it’s for

• Front-end developers
• Designers learning CSS
• Students exploring selectors
• Anyone who’s ever thought “wait… why did that element get selected?”

Tip 💡

Try switching between presets and then fine-tuning the values — it’s one of the fastest ways to build intuition around nth-child() behavior.