Can I change the checkbox size using CSS?

Is it possible to set the size of a checkbox using CSS or HTML across browsers?

width and size work in IE6+, but not with Firefox, where the checkbox stays 16x16 even if I set a smaller size.

It's a little ugly (due to the scaling up), but it works on most newer browsers:

input[type=checkbox]
{
  /* Double-sized Checkboxes */
  -ms-transform: scale(2); /* IE */
  -moz-transform: scale(2); /* FF */
  -webkit-transform: scale(2); /* Safari and Chrome */
  -o-transform: scale(2); /* Opera */
  transform: scale(2);
  padding: 10px;
}

/* Might want to wrap a span around your checkbox text */
.checkboxtext
{
  /* Checkbox text */
  font-size: 110%;
  display: inline;
}

<input  type="checkbox" name="optiona" id="opta" checked />
<span class="checkboxtext">
  Option A
</span>
<input type="checkbox" name="optionb" id="optb" />
<span class="checkboxtext">
  Option B
</span>
<input type="checkbox" name="optionc" id="optc" />
<span class="checkboxtext">
  Option C
</span>

Working solution for all modern browsers.

input[type=checkbox] {
    transform: scale(1.5);
}

<label><input type="checkbox"> Test</label>

---

Compatibility:

• IE: 10+
• FF: 16+
• Chrome: 36+
• Safari: 9+
• Opera: 23+
• iOS Safari: 9.2+
• Chrome for Android: 51+

---

Appearance:

• Chrome 58 (May 2017), Windows 10

An easy solution is use the property zoom:

input[type="checkbox"] {
    zoom: 1.5;
}

<input type="checkbox" />

2020 version - using pseudo-elements, size depends on font size.

Default checkbox/radio is rendered outside of screen, but CSS creates virtual elements very similar to default elements. Supports all browsers, no blur. Size depends on font size. Keyboard actions (space, tabs) are also supported.

https://jsfiddle.net/ohf7nmzy/2/

body{
	padding:0 20px;
}
.big{
	font-size: 50px;
}

/* CSS below will force radio/checkbox size be same as font size */
label{
	position: relative;
	line-height: 1.4;
}
/* radio */
input[type=radio]{
	width: 1em;
	font-size: inherit;
	margin: 0;
	transform: translateX(-9999px);
}
input[type=radio] + label:before{
	position: absolute;
	content: '';
	left: -1.3em;
	top: 0;
	width: 1em;
	height: 1em;
	margin: 0;
	border:none;
	border-radius: 50%;
	background-color: #bbbbbb;
}
input[type=radio] + label:after{
	position: absolute;
	content: '';
	left: -1.3em;
	top: 0;
	width: 1em;
	height: 1em;
	margin: 0;
	border: none;
	background-color: white;
	border-radius: 50%;
	transform: scale(0.8);
}
/*checked*/
input[type=radio]:checked + label:before{
	position:absolute;
	content:'';
	left: -1.3em;
	top: 0;
	width: 1em;
	height: 1em;
	margin: 0;
	border: none;
	background-color: #3b88fd;
}
input[type=radio]:checked + label:after{
	position: absolute;
	content: '';
	left: -1.3em;
	top: 0;
	width: 1em;
	height: 1em;
	margin: 0;
	border: none;
	background-color: white;
	border-radius: 50%;
	transform: scale(0.3);
}
/*focused*/
input[type=radio]:focus + label:before{
	border: 0.2em solid #8eb9fb;
	margin-top: -0.2em;
	margin-left: -0.2em;
	box-shadow: 0 0 0.3em #3b88fd;
}


/*checkbox/*/
input[type=checkbox]{
	width: 1em;
	font-size: inherit;
	margin: 0;
	transform: translateX(-9999px);
}
input[type=checkbox] + label:before{
	position: absolute;
	content: '';
	left: -1.3em;
	top: 0;
	width: 1em;
	height: 1em;
	margin: 0;
	border:none;
	border-radius: 10%;
	background-color: #bbbbbb;
}
input[type=checkbox] + label:after{
	position: absolute;
	content: '';
	left: -1.3em;
	top: 0;
	width: 1em;
	height: 1em;
	margin: 0;
	border: none;
	background-color: white;
	border-radius: 10%;
	transform: scale(0.8);
}
/*checked*/
input[type=checkbox]:checked + label:before{
	position:absolute;
	content:'';
	left: -1.3em;
	top: 0;
	width: 1em;
	height: 1em;
	margin: 0;
	border: none;
	background-color: #3b88fd;
}
input[type=checkbox]:checked + label:after{
	position: absolute;
	content: "\2713";
	left: -1.3em;
	top: 0;
	width: 1em;
	height: 1em;
	margin: 0;
	border: none;
	background-color: #3b88fd;
	border-radius: 10%;
	color: white;
	text-align: center;
	line-height: 1;
}
/*focused*/
input[type=checkbox]:focus + label:before{
	border: 0.1em solid #8eb9fb;
	margin-top: -0.1em;
	margin-left: -0.1em;
	box-shadow: 0 0 0.2em #3b88fd;
}

<input type="checkbox" name="checkbox_1" id="ee" checked /> 
<label for="ee">Checkbox small</label>

<br />

<input type="checkbox" name="checkbox_2" id="ff" /> 
<label for="ff">Checkbox small</label>

<hr />

<div class="big">
	<input type="checkbox" name="checkbox_3" id="gg" checked /> 
	<label for="gg">Checkbox big</label>

	<br />

	<input type="checkbox" name="checkbox_4" id="hh" /> 
	<label for="hh">Checkbox big</label>
</div>


<hr />


<input type="radio" name="radio_1" id="aa" value="1" checked /> 
<label for="aa">Radio small</label>

<br />

<input type="radio" name="radio_1" id="bb" value="2" /> 
<label for="bb">Radio small</label>

<hr />

<div class="big">
	<input type="radio" name="radio_2" id="cc" value="1" checked /> 
	<label for="cc">Radio big</label>

	<br />

	<input type="radio" name="radio_2" id="dd" value="2" /> 
	<label for="dd">Radio big</label>
</div>

2017 version - using zoom or scale

Browser will use non-standard zoom feature if it is supported (nice quality) or standard transform: scale (blurry on Safari) as fallback.

https://jsfiddle.net/ksvx2txb/11/

@supports (zoom:2) {
	input[type="radio"],  input[type=checkbox]{
	zoom: 2;
	}
}
@supports not (zoom:2) {
	input[type="radio"],  input[type=checkbox]{
		transform: scale(2);
		margin: 15px;
	}
}
label{
  /* fix vertical align issues */
	display: inline-block;
	vertical-align: top;
	margin-top: 10px;
}

<input type="radio" name="aa" value="1" id="aa" checked /> 
<label for="aa">Radio 1</label>
<br />
<input type="radio" name="aa" value="2" id="bb" /> 
<label for="bb">Radio 2</label>

<br /><br />

<input  type="checkbox" name="optiona" id="cc" checked /> 
<label for="cc">Checkbox 1</label>
<br />
<input  type="checkbox" name="optiona" id="dd" /> 
<label for="dd">Checkbox 1</label>

I just came out with this:

input[type="checkbox"] {display:none;}
input[type="checkbox"] + label:before {content:"☐";}
input:checked + label:before {content:"☑";}
label:hover {color:blue;}

<input id="check" type="checkbox" /><label for="check">Checkbox</label>

Of course, thanks to this, you can change the value of content to your needs and use an image if you wish or use another font...

The main interest here is that:

1. The checkbox size stays proportional to the text size

2. You can control the aspect, the color, the size of the checkbox

3. No extra HTML needed !

4. Only 3 lines of CSS needed (the last one is just to give you ideas)

Edit: As pointed out in the comment, the checkbox won't be accessible by key navigation. You should probably add tabindex=0 as a property for your label to make it focusable.

Preview:
http://jsfiddle.net/h4qka9td/

*,*:after,*:before {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
  padding: 0;
  margin: 0;
}

.switch {
  margin: 50px auto;
  position: relative;
}

.switch label {
  width: 100%;
  height: 100%;
  position: relative;
  display: block;
}

.switch input {
  top: 0; 
  right: 0; 
  bottom: 0; 
  left: 0;
  opacity: 0;
  z-index: 100;
  position: absolute;
  width: 100%;
  height: 100%;
  cursor: pointer;
}

/* DEMO 3 */

.switch.demo3 {
  width: 180px;
  height: 50px;
}

.switch.demo3 label {
  display: block;
  width: 100%;
  height: 100%;
  background: #a5a39d;
  border-radius: 40px;
  box-shadow:
      inset 0 3px 8px 1px rgba(0,0,0,0.2),
      0 1px 0 rgba(255,255,255,0.5);
}

.switch.demo3 label:after {
  content: "";
  position: absolute;
  z-index: -1;
  top: -8px; right: -8px; bottom: -8px; left: -8px;
  border-radius: inherit;
  background: #ababab;
  background: -moz-linear-gradient(#f2f2f2, #ababab);
  background: -ms-linear-gradient(#f2f2f2, #ababab);
  background: -o-linear-gradient(#f2f2f2, #ababab);
  background: -webkit-gradient(linear, 0 0, 0 100%, from(#f2f2f2), to(#ababab));
  background: -webkit-linear-gradient(#f2f2f2, #ababab);
  background: linear-gradient(#f2f2f2, #ababab);
  box-shadow: 0 0 10px rgba(0,0,0,0.3),
        0 1px 1px rgba(0,0,0,0.25);
}

.switch.demo3 label:before {
  content: "";
  position: absolute;
  z-index: -1;
  top: -18px; right: -18px; bottom: -18px; left: -18px;
  border-radius: inherit;
  background: #eee;
  background: -moz-linear-gradient(#e5e7e6, #eee);
  background: -ms-linear-gradient(#e5e7e6, #eee);
  background: -o-linear-gradient(#e5e7e6, #eee);
  background: -webkit-gradient(linear, 0 0, 0 100%, from(#e5e7e6), to(#eee));
  background: -webkit-linear-gradient(#e5e7e6, #eee);
  background: linear-gradient(#e5e7e6, #eee);
  box-shadow:
      0 1px 0 rgba(255,255,255,0.5);
  -webkit-filter: blur(1px);
  -moz-filter: blur(1px);
  -ms-filter: blur(1px);
  -o-filter: blur(1px);
  filter: blur(1px);
}

.switch.demo3 label i {
  display: block;
  height: 100%;
  width: 60%;
  border-radius: inherit;
  background: silver;
  position: absolute;
  z-index: 2;
  right: 40%;
  top: 0;
  background: #b2ac9e;
  background: -moz-linear-gradient(#f7f2f6, #b2ac9e);
  background: -ms-linear-gradient(#f7f2f6, #b2ac9e);
  background: -o-linear-gradient(#f7f2f6, #b2ac9e);
  background: -webkit-gradient(linear, 0 0, 0 100%, from(#f7f2f6), to(#b2ac9e));
  background: -webkit-linear-gradient(#f7f2f6, #b2ac9e);
  background: linear-gradient(#f7f2f6, #b2ac9e);
  box-shadow:
      inset 0 1px 0 white,
      0 0 8px rgba(0,0,0,0.3),
      0 5px 5px rgba(0,0,0,0.2);
}

.switch.demo3 label i:after {
  content: "";
  position: absolute;
  left: 15%;
  top: 25%;
  width: 70%;
  height: 50%;
  background: #d2cbc3;
  background: -moz-linear-gradient(#cbc7bc, #d2cbc3);
  background: -ms-linear-gradient(#cbc7bc, #d2cbc3);
  background: -o-linear-gradient(#cbc7bc, #d2cbc3);
  background: -webkit-gradient(linear, 0 0, 0 100%, from(#cbc7bc), to(#d2cbc3));
  background: -webkit-linear-gradient(#cbc7bc, #d2cbc3);
  background: linear-gradient(#cbc7bc, #d2cbc3);
  border-radius: inherit;
}

.switch.demo3 label i:before {
  content: "off";
  text-transform: uppercase;
  font-style: normal;
  font-weight: bold;
  color: rgba(0,0,0,0.4);
  text-shadow: 0 1px 0 #bcb8ae, 0 -1px 0 #97958e;
  font-family: Helvetica, Arial, sans-serif;
  font-size: 24px;
  position: absolute;
  top: 50%;
  margin-top: -12px;
  right: -50%;
}

.switch.demo3 input:checked ~ label {
  background: #9abb82;
}

.switch.demo3 input:checked ~ label i {
  right: -1%;
}

.switch.demo3 input:checked ~ label i:before {
  content: "on";
  right: 115%;
  color: #82a06a;
  text-shadow: 
    0 1px 0 #afcb9b,
    0 -1px 0 #6b8659;
}

<div class="switch demo3">
  <input type="checkbox">
  <label><i></i>
  </label>
</div>

<div class="switch demo3">
  <input type="checkbox" checked>
  <label><i></i>
  </label>
</div>

The appearance of checkboxes seems to be fixed by default. But as pointed out by Worthy7 this can be remedied using CSS appearance property. It will make checkboxes completely empty, so you can define your own appearance. What is nice about this: You can use your existing HTML code. Downside: It is experimental technology. Edge (legacy) and IE do not use the custom style.

Here are the needed CSS styles:

input[type=checkbox] {
    width: 14mm;
    -webkit-appearance: none;
    -moz-appearance: none;
    height: 14mm;
    border: 0.1mm solid black;
}

input[type=checkbox]:checked {
    background-color: lightblue;
}

input[type=checkbox]:checked:after {
    margin-left: 4.3mm;
    margin-top: -0.4mm;
    width: 3mm;
    height: 10mm;
    border: solid white;
    border-width: 0 2mm 2mm 0;
    -webkit-transform: rotate(45deg);
    -moz-transform: rotate(45deg);
    -ms-transform: rotate(45deg);
    transform: rotate(45deg);
    content: "";
    display: inline-block;
}

<label><input type="checkbox"> Test</label>

Screenshots:

Chrome:

Firefox:

Edge:

Edge (legacy):

IE:

I think the simplest solution is re-style the checkbox as some users suggest. The CSS below is working for me, only requires a few lines of CSS, and answers the OP question:

input[type=checkbox] {
    -webkit-appearance: none;
    -moz-appearance: none;
    vertical-align: middle;
    width: 14px; 
    height: 14px;
    font-size: 14px;
    background-color: #eee;
}

input[type=checkbox]:checked:after {
    position: relative;
    bottom: 3px;
    left: 1px;
    color: blue;
    content: "\2713"; /* check mark */
}

As mentioned in this post, the zoom property seems not to work on Firefox, and transforms may cause undesired effects.

Tested on Chrome and Firefox, should work for all modern browsers. Just change the properties (colors, size, bottom, left, etc.) to your needs. Hope it helps!

I was looking to make a checkbox that was just a little bit larger and looked at the source code for 37Signals Basecamp to find the following solution-

You can change the font size to make the checkbox slightly larger:

font-size: x-large;

Then, you can align the checkbox properly by doing:

vertical-align: top;
margin-top: 3px; /* change to center it */

You can make checkboxes larger in Safari — which is generally resistant to the usual approaches — with this attribute: -webkit-transform: scale(1.3, 1.3);

Source

My understanding is that this isn't easy at all to do cross-browser. Instead of trying to manipulate the checkbox control, you could always build your own implementation using images, javascript, and hidden input fields. I'm assuming this is similar to what niceforms is (from Staicu lonut's answer above), but wouldn't be particularly difficult to implement. I believe jQuery has a plugin to allow for this custom behavior as well (will look for the link and post here if I can find it).

This should work

input {
  width: 25px;
  height: 25px;
}

It worked for me for Firefox and Chrome and iPhone's Firefox, Chrome and Safari at least.

I found this CSS-only library to be very helpful: https://lokesh-coder.github.io/pretty-checkbox/

Or, you could roll your own with this same basic concept, similar to what @Sharcoux posted. It's basically:

• Hide the normal checkbox (opacity 0 and placed where it would go)
• Add a css-based fake checkbox
• Use input:checked~div label for the checked style
• make sure your <label> is clickable using for=yourinputID

.pretty {
  position: relative;
  margin: 1em;
}
.pretty input {
  position: absolute;
  left: 0;
  top: 0;
  min-width: 1em;
  width: 100%;
  height: 100%;
  z-index: 2;
  opacity: 0;
  margin: 0;
  padding: 0;
  cursor: pointer;
}
.pretty-inner {
  box-sizing: border-box;
  position: relative;
}
.pretty-inner label {
  position: initial;
  display: inline-block;
  font-weight: 400;
  margin: 0;
  text-indent: 1.5em;
  min-width: calc(1em + 2px);
}
.pretty-inner label:after,
.pretty-inner label:before {
  content: '';
  width: calc(1em + 2px);
  height: calc(1em + 2px);
  display: block;
  box-sizing: border-box;
  border-radius: 0;
  border: 1px solid transparent;
  z-index: 0;
  position: absolute;
  left: 0;
  top: 0;
  background-color: transparent;
}
.pretty-inner label:before {
  border-color: #bdc3c7;
}
.pretty input:checked~.pretty-inner label:after {
  background-color: #00bb82;
  width: calc(1em - 6px);
  height: calc(1em - 6px);
  top: 4px;
  left: 4px;
}


/* Add checkmark character style */
.pretty input:checked~.pretty-inner.checkmark:after {
  content: '\2713';
  color: #fff;
  position: absolute;
  font-size: 0.65em;
  left: 6px;
  top: 3px;
}



body {
  font-size: 20px;
  font-family: sans-serif;
}

<div class="pretty">
	<input type="checkbox" id="demo" name="demo">
	<div class="pretty-inner"><label for="demo">I agree.</label></div>
</div>

<div class="pretty">
	<input type="checkbox" id="demo" name="demo">
	<div class="pretty-inner checkmark"><label for="demo">Please check the box.</label></div>
</div>

use this css code

input[type=checkbox]
{
  /* Double-sized Checkboxes */
  -ms-transform: scale(1.5); /* IE */
  -moz-transform: scale(1.5); /* FF */
  -webkit-transform: scale(1.5); /* Safari and Chrome */
  -o-transform: scale(1.5); /* Opera */
  transform: scale(1.5);
  padding: 10px;
}

The other answers showed a pixelated checkbox, while I wanted something beautiful. The result looks like this:

Even though this version is more complicated I think it's worth giving it a try.

.checkbox-list__item {
  position: relative;
  padding: 10px 0;
  display: block;
  cursor: pointer;
  margin: 0 0 0 34px;
  border-bottom: 1px solid #b4bcc2;
}
.checkbox-list__item:last-of-type {
  border-bottom: 0;
}

.checkbox-list__check {
  width: 18px;
  height: 18px;
  border: 3px solid #b4bcc2;
  position: absolute;
  left: -34px;
  top: 50%;
  margin-top: -12px;
  transition: border .3s ease;
  border-radius: 5px;
}
.checkbox-list__check:before {
  position: absolute;
  display: block;
  width: 18px;
  height: 22px;
  top: -2px;
  left: 0px;
  padding-left: 2px;
  background-color: transparent;
  transition: background-color .3s ease;
  content: '\2713';
  font-family: initial;
  font-size: 19px;
  color: white;
}

input[type="checkbox"]:checked ~ .checkbox-list__check {
  border-color: #5bc0de;
}
input[type="checkbox"]:checked ~ .checkbox-list__check:before {
  background-color: #5bc0de;
}

<label class="checkbox-list__item">
  <input class="checkbox_buttons" type="checkbox" checked="checked" style="display: none;">
  <div class="checkbox-list__check"></div>
</label>

JSFiddle: https://jsfiddle.net/asbd4hpr/

The problem is Firefox doesn't listen to width and height. Disable that and your good to go.

input[type=checkbox] {
    width: 25px;
    height: 25px;
    -moz-appearance: none;
}

<label><input type="checkbox"> Test</label>

My reputation is slightly too low to post comments, but I made a modification to Jack Miller's code above in order to get it to not change size when you check and uncheck it. This was causing text alignment problems for me.

    input[type=checkbox] {
        width: 17px;
        -webkit-appearance: none;
        -moz-appearance: none;
        height: 17px;
        border: 1px solid black;
    }

    input[type=checkbox]:checked {
        background-color: #F58027;
    }

    input[type=checkbox]:checked:after {
        margin-left: 4px;
        margin-top: -1px;
        width: 4px;
        height: 12px;
        border: solid white;
        border-width: 0 2px 2px 0;
        -webkit-transform: rotate(45deg);
        -moz-transform: rotate(45deg);
        -ms-transform: rotate(45deg);
        transform: rotate(45deg);
        content: "";
        display: inline-block;
    }
    input[type=checkbox]:after {
        margin-left: 4px;
        margin-top: -1px;
        width: 4px;
        height: 12px;
        border: solid white;
        border-width: 0;
        -webkit-transform: rotate(45deg);
        -moz-transform: rotate(45deg);
        -ms-transform: rotate(45deg);
        transform: rotate(45deg);
        content: "";
        display: inline-block;
    }

<label><input type="checkbox"> Test</label>

You can change the height and width in the code below

.checkmark {
    position: absolute;
    top: 0;
    left: 0;
    height: 20px;
    width: 20px;
    border-radius:5px;
    border:1px solid #ff7e02;
}

<div class="check">

     <label class="container1">Architecture/Landscape
										  

    <input type="checkbox" checked="checked">
										  

    <span class="checkmark"></span>
								 

	</label>
</div>