Migrate Bootstrap to Tailwind CSS
Stop rewriting every btn-primary and col-md-6 by hand. ExtractCSS reads the computed styles from your running Bootstrap app and converts them to clean Tailwind utility classes.
Manual Bootstrap-to-Tailwind migration is slow, fragile, and boring.
You have decided to move from Bootstrap to Tailwind. Good call. But now you are staring at hundreds of components full of card, d-flex, mb-3, and custom SCSS overrides layered on top. The class names look similar between frameworks, but the underlying values are different. Bootstrap's p-3 is 1rem. Tailwind's p-3 is 0.75rem.
A search-and-replace won't work. A regex-based converter can handle some simple class mappings, but it misses your custom variables, your Bootstrap theme overrides, your SCSS mixins, and any component that uses more than two CSS properties together. You end up eyeballing DevTools, comparing padding values, and hoping the colors look close enough.
Most teams spend 2-4 weeks migrating a medium-sized Bootstrap app. Roughly half of that time goes to hunting down subtle visual regressions: a card with the wrong shadow, a badge with the wrong border-radius, a navbar with a 1px gap that wasn't there before.
Let the browser do the translation.
ExtractCSS does not try to map Bootstrap classes to Tailwind classes. Instead, it reads the computed styles that the browser actually renders. This means it sees the final pixel values after all your SCSS variables, theme overrides, mixins, and media queries have been resolved. It then maps those computed values to the nearest Tailwind design tokens.
The result: a Bootstrap btn btn-primary with a custom $primary: #4f46e5 becomes Tailwind bg-indigo-600 text-white px-4 py-2 rounded-md font-medium. Not because it matched a lookup table, but because those are the actual values the browser computed.
It works with Bootstrap 3, 4, and 5. It works with Bootswatch themes. It works with your custom SCSS build where half the variables have been redefined. If the browser can render it, ExtractCSS can read it.
How it works
- 1
Open your Bootstrap app in Chrome
Navigate to the page you want to migrate. It can be localhost, a staging server, or production. ExtractCSS works on any URL.
- 2
Click the component you want to convert
Activate the extension and hover over any element. A blue overlay shows what will be extracted. Click to capture the component and all its children.
- 3
Adjust the tolerance
The snapper maps your Bootstrap values to the nearest Tailwind tokens. You can tighten or loosen the tolerance per category: colors, spacing, box-shadow, and timing curves. Too loose and you lose fidelity; too tight and you get arbitrary values. The default "Balanced" setting works well for most Bootstrap components.
- 4
Copy the Tailwind HTML
The output panel shows clean HTML with Tailwind classes. Paste it into your project. The live preview lets you compare side-by-side before you commit to anything.
Common Bootstrap patterns and how they convert
Since ExtractCSS works from computed styles rather than class names, it handles every Bootstrap pattern the same way. Here are a few familiar components and what the output looks like.
Grid layout (row / col-md-6)
Bootstrap's 12-column grid compiles to flexbox with percentage widths. ExtractCSS reads the computed display: flex, flex-wrap: wrap, and width percentages, then maps them to Tailwind's flex, flex-wrap, and w-1/2 utilities. Responsive breakpoints come through too: if your col-md-6 kicks in at 768px, you get md:w-1/2.
Cards (card / card-body)
Bootstrap cards have specific border-radius, padding, and box-shadow values. The snapper picks up all of these and finds the nearest Tailwind tokens. A default Bootstrap card with border-radius: 0.375rem maps to rounded-md. If you have customized $card-border-radius in your SCSS, ExtractCSS sees the final value and matches accordingly.
Utilities (d-flex, text-center, mt-3)
These are the easiest to migrate but also the trickiest to get right in bulk. Bootstrap's mt-3 is margin-top: 1rem; Tailwind's mt-4 is also 1rem. Get the numbers wrong and everything shifts by a few pixels. ExtractCSS avoids this entirely by reading the actual pixel value from the browser.
Buttons and forms
Bootstrap buttons carry background, padding, border, border-radius, font-size, font-weight, line-height, and transition properties. That is 8+ CSS declarations per button variant. ExtractCSS captures all of them in one click, including hover and focus states. Same for form controls: input heights, focus ring colors, placeholder styles, and disabled states all come through.
Why computed styles beat class-name mapping
Most Bootstrap-to-Tailwind converters work by mapping class names. They see btn-primary and output bg-blue-600 text-white. That works fine until you have customized your Bootstrap theme, used SCSS mixins, or combined utility classes with custom CSS.
ExtractCSS takes a different approach. It runs in the browser, where every CSS rule has already been parsed, cascaded, and computed. There is no guesswork about which SCSS variable was used or which media query applies at the current viewport. The browser already figured that out. ExtractCSS just reads the answer.
This also means it handles third-party Bootstrap plugins, Bootswatch themes, and any CSS you wrote on top of Bootstrap. If the browser renders it, the extension can extract it.
Tips for a smooth migration
- 1.Migrate by component, not by page. Extract one card, one navbar, one form at a time. Replace them in isolation so you can test each piece.
- 2.Use the token panels to align your design system. After extraction, the color and spacing panels show you every value the component uses. You can swap Bootstrap's default blue (#0d6efd) for your Tailwind theme color before copying.
- 3.Check responsive breakpoints. Bootstrap and Tailwind use different default breakpoints. ExtractCSS captures the media queries as they are, so verify the responsive behavior after pasting.
- 4.Run both frameworks in parallel. You don't need to rip out Bootstrap on day one. Many teams run both frameworks side-by-side during migration, converting one section at a time.
Extract your first component in the next 60 seconds
Install the extension. Navigate to any website. Click the component you want. Get clean Tailwind code. It really is that simple.