stroke-width

The stroke-width attribute is a presentation attribute defining the width of the stroke to be applied to the shape.

As a presentation attribute, it can be applied to any element but it only has effect on shapes and text context elements, including: <altGlyph>, <circle>, <ellipse>, <line>, <path>, <polygon>, <polyline>, <rect>, <text>, <textPath>, <tref>, and <tspan>

html,body,svg { height:100% }

<svg viewBox="0 0 30 10" xmlns="http://www.w3.org/2000/svg">
  <!-- Default stroke width: 1 -->
  <circle cx="5" cy="5" r="3" stroke="green" />

  <!-- Stroke width as a number -->
  <circle cx="15" cy="5" r="3" stroke="green"
          stroke-width="3" />

  <!-- Stroke width as a percentage -->
  <circle cx="25" cy="5" r="3" stroke="green"
          stroke-width="2%" />
</svg>

Usage notes

Note: A percentage value is always computed as a percentage of the normalized viewBox diagonal length.

Browser compatibility

Specification