Triangle In CSS

ORIGINAL ARTICLE: 5 Ways To Create A Triangle With CSS

Probably the easiest way to add a triangle in a web page is to simply draw it in an image and add the image to the web page. There are many secrets to drawing the perfect triangle and you can read how to do that in Photoshop in this article: Create A Triangle in Photoshop or download this free pack of triangle shapes for Photoshop.

In this post I will show you how to create a triangle with CSS & HTML.

Here’s an overview of the different methods I will use:

• Create a triangle using CSS border
• Create a triangle with CSS gradients (linear-gradient and conical-gradient)
• Create a triangle using overflow and transform
• Create a triangle using clip-path

Using border to Create a Triangle in CSS

The following code will create a div with 4 triangles inside

HTML:

<div class="triangle"></div>

CSS:

.triangle {
    border-left: 20px solid cyan;
    border-right: 20px solid red;
    border-bottom: 20px solid green;
    border-top: 20px solid blue;
    display: inline-block;
}

Results into

Making all borders transparent except the bottom border:

.triangle-up {
    border-left: 20px solid transparent;
    border-right: 20px solid transparent;
    border-bottom: 20px solid green;
    border-top: 20px solid transparent;
    display: inline-block;
}

we get

How To Make An Equilateral Triangle Using border

CSS:

.triangle-up-equilateral {
    --side-size: 20px;
    border-left: var(--side-size) solid transparent;
    border-right: var(--side-size) solid transparent;
    border-bottom: calc(2 * var(--side-size) * 0.866) solid green;
    border-top: var(--side-size) solid transparent;
    display: inline-block;
}

How To Create a Triangle Using CSS Gradients

CSS:

.triangle {
    width: 200px;
    height: 200px;
    background: linear-gradient(to bottom right, #fff 0%, #fff 50%, green 50%, green 100%);
}

renders:

How To Create a Triangle Using CSS transform and overflow

CSS code:

.triangle-element {
    width: 20px;
    height: 20px;
    overflow: hidden;
    position: relative;
    margin: 10px;
}
.triangle-element:after {
    content: '';
    background: green;
    width: 142%;
    height: 142%;
    position: absolute;
    transform: rotate(45deg) translate(-71%,0);
}

How To Create A Triangle In CSS Using clip-path

CSS Code:

.triangle-element {
    width: 40px;
    height: 40px;
    background: green;
    clip-path: polygon(50% 0%, 0% 100%, 100% 100%);
}

Conclusion

There are a lot of uses for triangles. From arrow symbol to map pins, from menu markers to chart elements.

Now you know how to create a triangle with CSS.

If you liked this tutorial, make sure to check out our Complete How-To Guide for creating and using CSS Circle Images or see how to create a CSS only bar chart in HTML.