---
title: background-size
slug: Web/CSS/background-size
translation_of: Web/CSS/background-size
---
<div>{{CSSRef}}</div>

<p><code style=""><font face="Open Sans, arial, x-locale-body, sans-serif"><span style="background-color: #ffffff;">Właściwość </span></font><strong>background-size</strong></code> określa wielkość elementu <code>background-image.</code> Obrazek może pozostać w jego domyślnych wymiarach, rozciągnięty do nowych wymiarów lub ustawiony tak, aby zajmował całą dostępną przestrzeń zachowując swoje proporcje.</p>

<div>{{EmbedInteractiveExample("pages/css/background-size.html")}}</div>

<p class="hidden">Źródło tego interaktywnego przykładu jest zlokalizowane na GitHub. Jeśli chcesz wspierać projekt interaktywnych przykładów sklonuj (clone) <a href="https://github.com/mdn/interactive-examples">https://github.com/mdn/interactive-examples</a> i wyślij nam pull request.</p>

<p>Przestrzenie nie zapełnione przez <code>background-image</code> wypełnia {{cssxref("background-color")}}, <code>background-color</code> będzie widoczny jeżeli obrazek jest przezroczysty.</p>

<h2 id="Syntax">Syntax</h2>

<pre class="brush: css no-line-numbers">/* Wartości słowne */
background-size: cover;
background-size: contain;

/* Właściwości z jedną wartością */
/* szerokość obrazka (wysokość stanie się 'auto') */
background-size: 50%;
background-size: 3.2em;
background-size: 12px;
background-size: auto;

/* Właściwości z dwoma wartościami */
/* pierwsza wartość: szerokość obrazka, druga wartość: wysokość */
background-size: 50% auto;
background-size: 3em 25%;
background-size: auto 6px;
background-size: auto auto;

/* Wiele teł */
background-size: auto, auto; /* Not to be confused with `auto auto` */
background-size: 50%, 25%, 25%;
background-size: 6px, auto, contain;

/* Wartości globalne */
background-size: inherit;
background-size: initial;
background-size: unset;
</pre>

<p>Właściwość <code>background-size</code> jest określana w jeden z podanych sposobów:</p>

<ul>
 <li>Używając wartości słownych <code><a href="#contain">contain</a></code> lub <code><a href="#cover">cover</a></code>.</li>
 <li>Używając tylko wartości długości, w tym przypadku wysokość jest domyślnie ustawiona na <code><a href="#auto">auto</a></code><a href="#auto">.</a></li>
 <li>Używając obu wartości (width i height), każda z wartości może być określona jako długość {{cssxref("&lt;length&gt;")}}, w procentach {{cssxref("&lt;percentage&gt;")}} lub <code><a href="#auto">auto</a></code>.</li>
</ul>

<p>Aby określić wielkość wielu teł, odziel wartości dla każdego tła przecinkami.</p>

<h3 id="Values">Values</h3>

<dl>
 <dt id="contain"><code>contain</code></dt>
 <dd>Skaluje obrazek do jak największych rozmiarów, bez jego rozciągania czy przycinania.</dd>
 <dt id="cover"><code>cover</code></dt>
 <dd>Skaluje obrazek do jak największych rozmiarów, bez jego rozciągania. Jeżeli proporcje obrazu są inne od elementu, jest on przycinany pionowo lub poziomo - tak, żeby nie zostało puste miejsce.</dd>
 <dt id="auto"><code>auto</code></dt>
 <dd>Skaluje tło w odpowiednim kierunku, po to aby zachować jego nieodłączne proporcje.</dd>
 <dt id="length">{{cssxref("&lt;length&gt;")}}</dt>
 <dd>Rozciąga obrazek w odpowiednim kierunku do określonej długości. Nie można używać wartości ujemnych.</dd>
 <dt id="percentage">{{cssxref("&lt;percentage&gt;")}}</dt>
 <dd>[do przetłumaczenia na: Polski]</dd>
 <dd>Stretches the image in the corresponding dimension to the specified percentage of the <em>background positioning area</em>. The background positioning area is determined by the value of {{cssxref("background-origin")}} (by default, the padding box). However, if the background's {{cssxref("background-attachment")}} value is <code>fixed</code>, the positioning area is instead the entire {{glossary("viewport")}}. Negative values are not allowed.</dd>
</dl>

<h3 id="Intrinsic_dimensions_and_proportions">Intrinsic dimensions and proportions</h3>

<p>The computation of values depends on the image's intrinsic dimensions (width and height) and intrinsic proportions (width-to-height ratio). These attributes are as follows:</p>

<ul>
 <li>A bitmap image (such as JPG) always has intrinsic dimensions and proportions.</li>
 <li>A vector image (such as SVG) does not necessarily have intrinsic dimensions. If it has both horizontal and vertical intrinsic dimensions, it also has intrinsic proportions. If it has no dimensions or only one dimension, it may or may not have proportions.</li>
 <li>CSS {{cssxref("&lt;gradient&gt;")}}s have no intrinsic dimensions or intrinsic proportions.</li>
 <li>Background images created with the {{cssxref("element()")}} function use the intrinsic dimensions and proportions of the generating element.</li>
</ul>

<div class="note">
<p><strong>Note:</strong> The behavior of <code>&lt;gradient&gt;</code>s changed in Gecko 8.0 {{geckoRelease("8.0")}}. Before this, they were treated as images with no intrinsic dimensions, but with intrinsic proportions identical to that of the background positioning area.</p>
</div>

<div class="note">
<p><strong>Note:</strong> In Gecko, background images created using the {{cssxref("element()")}} function are currently treated as images with the dimensions of the element, or of the background positioning area if the element is SVG, with the corresponding intrinsic proportion. This is non-standard behavior.</p>
</div>

<p>Based on the intrinsic dimensions and proportions, the rendered size of the background image is computed as follows:</p>

<dl>
 <dt>If both components of <code>background-size</code> are specified and are not <code>auto</code>:</dt>
 <dd>The background image is rendered at the specified size.</dd>
 <dt>If the <code>background-size</code> is <code>contain</code> or <code>cover</code>:</dt>
 <dd>While preserving its intrinsic proportions, the image is rendered at the largest size contained within, or covering, the background positioning area. If the image has no intrinsic proportions, then it's rendered at the size of the background positioning area.</dd>
 <dt>If the <code>background-size</code> is <code>auto</code> or <code>auto auto</code>:</dt>
 <dd>
 <ul>
  <li>If the image has both horizontal and vertical intrinsic dimensions, it's rendered at that size.</li>
  <li>If the image has no intrinsic dimensions and has no intrinsic proportions, it's rendered at the size of the background positioning area.</li>
  <li>If the image has no intrinsic dimensions but has intrinsic proportions, it's rendered as if <code>contain</code> had been specified instead.</li>
  <li>If the image has only one intrinsic dimension and has intrinsic proportions, it's rendered at the size corresponding to that one dimension. The other dimension is computed using the specified dimension and the intrinsic proportions.</li>
  <li>If the image has only one intrinsic dimension but has no intrinsic proportions, it's rendered using the specified dimension and the other dimension of the background positioning area.</li>
 </ul>
 </dd>
 <dd>
 <div class="note"><strong>Note:</strong> SVG images have a <code><a href="/en-US/docs/Web/SVG/Attribute/preserveAspectRatio">preserveAspectRatio</a></code> attribute that defaults to the equivalent of <code>contain</code>. In Firefox 43, as opposed to Chrome 52, an explicit <code>background-size</code> causes <code>preserveAspectRatio</code> to be ignored.</div>
 </dd>
 <dt>If the <code>background-size</code> has one <code>auto</code> component and one non-<code>auto</code> component:</dt>
 <dd>
 <ul>
  <li>If the image has intrinsic proportions, it's stretched to the specified dimension. The unspecified dimension is computed using the specified dimension and the intrinsic proportions.</li>
  <li>If the image has no intrinsic proportions, it's stretched to the specified dimension. The unspecified dimension is computed using the image's corresponding intrinsic dimension, if there is one. If there is no such intrinsic dimension, it becomes the corresponding dimension of the background positioning area.</li>
 </ul>
 </dd>
</dl>

<div class="note">
<p><strong>Note:</strong> Background sizing for vector images that lack intrinsic dimensions or proportions is not yet fully implemented in all browsers. Be careful about relying on the behavior described above, and test in multiple browsers to be sure the results are acceptable.</p>
</div>

<h3 id="Formal_syntax">Formal syntax</h3>

{{csssyntax}}

<h2 id="Examples">Examples</h2>

<p>Please see <a href="/en-US/docs/Web/CSS/CSS_Backgrounds_and_Borders/Scaling_background_images">Scaling background images</a> for examples.</p>

<h2 id="Notes">Notes</h2>

<p>If you use a <code>&lt;gradient&gt;</code> as the background and specify a <code>background-size</code> to go with it, it's best not to specify a size that uses a single <code>auto</code> component, or is specified using only a width value (for example, <code>background-size: 50%</code>). Rendering of <code>&lt;gradient&gt;</code>s in such cases changed in Firefox 8, and at present is generally inconsistent across browsers, which do not all implement rendering in full accordance with <a href="http://www.w3.org/TR/css3-background/#the-background-size" title="http://www.w3.org/TR/css3-background/#the-background-size">the CSS3 <code>background-size</code> specification</a> and with <a href="http://dev.w3.org/csswg/css3-images/#gradients" title="http://dev.w3.org/csswg/css3-images/#gradients">the CSS3 Image Values gradient specification</a>.</p>

<pre class="brush: css">.gradient-example {
  width: 50px;
  height: 100px;
  background-image: linear-gradient(blue, red);

  /* Not safe to use */
  background-size: 25px;
  background-size: 50%;
  background-size: auto 50px;
  background-size: auto 50%;

  /* Safe to use */
  background-size: 25px 50px;
  background-size: 50% 50%;
}
</pre>

<p>Note that it's particularly not recommended to use a pixel dimension and an <code>auto</code> dimension with a <code>&lt;gradient&gt;</code>, because it's impossible to replicate rendering in versions of Firefox prior to 8, and in browsers not implementing Firefox 8's rendering, without knowing the exact size of the element whose background is being specified.</p>

<h2 id="Specifications" name="Specifications">Specifications</h2>

<table class="standard-table">
 <thead>
  <tr>
   <th scope="col">Specification</th>
   <th scope="col">Status</th>
   <th scope="col">Comment</th>
  </tr>
 </thead>
 <tbody>
  <tr>
   <td>{{SpecName('CSS3 Backgrounds', '#the-background-size', 'background-size')}}</td>
   <td>{{Spec2('CSS3 Backgrounds')}}</td>
   <td>Initial definition.</td>
  </tr>
 </tbody>
</table>

<p>{{cssinfo}}</p>

<h2 id="Browser_compatibility" name="Browser_compatibility">Browser compatibility</h2>

<p class="hidden">The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out <a href="https://github.com/mdn/browser-compat-data">https://github.com/mdn/browser-compat-data</a> and send us a pull request.</p>

<p>{{Compat("css.properties.background-size")}}</p>

<h2 id="See_also">See also</h2>

<ul>
 <li><a href="/en-US/docs/CSS/Scaling_background_images" title="CSS/Scaling_background_images">Scaling background images</a></li>
 <li><a href="/en-US/docs/Web/CSS/Scaling_of_SVG_backgrounds">Scaling of SVG backgrounds</a></li>
 <li>{{cssxref("object-fit")}}</li>
</ul>