A slider is a widget with which a user may set a value by moving an indicator, usually in a horizontal fashion. The user may also click on a point on the slider to change the setting. It is different from a scrollbar in that it is typically used to adjust a value without changing the format of the display or the other information on the screen. A slider is used to set defined, contiguous values or a range of discrete values. It is a good choice when values have a relative quantity, not a numeric value. Usually, changes made on the slider are shown immediately. That instant feedback supports input that is not necessarily precise. Compared with spin controls a slider provides faster changes within a larger range but with lower accuracy. Sliders are almost solely operable by mouse.


Is this the right control?

  • Use a slider when adjusting the value relative to its current value is more important than choosing an absolute value.
  • Use a slider when it is useful for the user to control the rate of change of the value in real time.
  • If the value is open-ended on one or both ends, consider using a Spin Box instead.


  • Try to give immediate feedback while the user makes a selection.
  • Size the control so that a user can easily set the desired value.
  • Don’t use a non-linear scale, e.g. logarithmic.


  • Label the slider with a text label to its left, using sentence capitalization. Provide an access key in the label that allows the user to give focus directly to the slider.

  • Align the label horizontally in line with the slider.

  • You can show the current value on the right of the slider or if space is very dense show it only as a tooltip when the slider is moved

    Show value always or as tooltip

  • Add the unit to the current value caption, if appropriate.

Slider with few steps

eg screen size, symbol-size

Spacing of slider components

  • Mark significant values along the length of the slider with text or checkmarks. Checkmark have a height of 4 px or 8 if you want to emphasize them.
  • Min/max labels are optional. Label min/max with real values, eg ‘640x480’ and ‘5120×2880’ in case of screen resolution.
  • Label the range of values; use checkmark and value label; don’t label every checkmark.

Slider with many steps

eg volume control, mouse speed, brightness

Exact value is not important

  • Don’t show checkmarks if the exact value is not important
  • Don’t show min/max label if the values don’t give the user additional information, (eg. don’t label them 0%, 100% when obvious)
  • If the exact value might be important to the user offer an input field instead of the current value label

Offer text input for exact value

Slider and Spinbox together

  • Use both a slider and spin box when the value is constrained at both ends, and when there is a large range of values (more than 20 steps) but precise control over the value is needed nevertheless.
  • Consider using only a slider or a spin box if a well-defined workflow makes the other redundant.
  • The values of the slider and spin box should be linked so changes to one are immediately reflect in another.
  • The spin box should be aligned with the long axis of the slider: if the slider is horizontal, the spin box should be to the right of the slider and aligned vertically with the center of the slider; if the slider is vertical, the spin box should be below the slider and aligned horizontally with the center of the slider.
  • Provide a single label using a text label above it or to the left of the widgets, using sentence capitalization. Provide an access key in the label that should give focus directly to the spin box.
  • Mark significant values along the length of the slider with text or tick marks.



Plasma Components