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Please note Primer v16 has changed the naming of these color classes. Check the migration guide to make sure your app is up to date.

Buttons are used for actions, like in forms, while textual hyperlinks are used for destinations, or moving from one page to another.

Note: When using a <button> element, always specify a type. When using a <a> element, always add role="button" for accessibility.

Button types


Use the standard — yet classy — .btn for form actions and general page actions. These are used extensively around the site.


Primary buttons are green and are used to indicate the primary action on a page. When you need your buttons to stand out, use .btn.btn-primary. You can use it with both button sizes—just add .btn-primary.


Outline buttons downplay an action as they appear like boxy links. Just add .btn-outline and go.


Danger buttons are red. They help reiterate that the intended action is important or potentially dangerous (e.g., deleting a repo or transferring ownership). Similar to the primary buttons, just add .btn-danger.

Button states


Adding an aria-selected="true" attribute will keep the button in a selected state. Typically used for BtnGroups.


Disable <button> and <a> elements with the aria-disabled="true" attribute.

Button variations


Next to the default size there is also a .btn-sm (small) and .btn-large option. Use them to decrese or increase the button size. This is useful for fitting a button next to an input or turning a button into a prominent call to action in hero sections.

Type scale utilities can be used to alter the font-size if needed. Padding is applied in em's so that it scales proportionally with the font-size.

Use .btn-large with a type scale utility to transform the text to a bigger size.

Block button

Make any button full-width by adding .btn-block. It adds width: 100%;, changes the display from inline-block to block, and centers the button text.

Create a button that looks like a link with .btn-link. Rather than using an <a> to trigger JS, this style on a <button> should be used for better accessibility.

The .btn-link class is not designed to be used with .btn; the overlapping styles are not compatible.

Invisible button

When you want a link, but you want it padded and line heighted like a button best for "cancel" actions on forms.

Hidden text button

Use .hidden-text-expander to indicate and toggle hidden text.

You can also make the expander appear inline by adding .inline.

Button with icons

Icons can be added to any button.

Icon-only button

Icon-only buttons .btn-octicon turn blue on hover. Use .btn-octicon-danger to turn an icon red on hover.

Close button

When using the octicon-x icon for a close button, add .close-button to remove the default button styles.

Button with counts

You can easily append a count to a small button. Add the .btn-with-count class to the .btn-sm and then add the .social-count after the button.

Be sure to clear the float added by the additional class.

You can also use the counter component within buttons:

Button groups

Have a hankering for a series of buttons that are attached to one another? Wrap them in a .BtnGroup and the buttons will be rounded and spaced automatically.

Use BtnGroup-item btn btn-sm for a smaller BtnGroup items.

Add .BtnGroup-parent to parent elements, like <form>s or <details>s, within .BtnGroups for proper spacing and rounded corners.

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Last edited by jonrohan on March 26, 2021