Horizontal volume sliders, for instance, are often unlabelled. Other than the VLC player volume slider, I've never seen a label saying that the right means things get louder.

How did that convention come about? Simply by people getting used to software engineers designing like that, or could it be something older than that, for instance the direction in which people read in.

In right-to-left reading areas, are sliders ever the other way around?

  • 3
    – Tim Grant
    Commented Nov 19, 2016 at 16:17
  • 2
    @TimGrant, can't believe the amount of wild guesses and crazy theories, when the real answer was as simple as this link, lol
    – Devin
    Commented Nov 19, 2016 at 20:29

4 Answers 4


Older than software engineers, but not a lot. Back in the days before MP3s and autotune, sound engineers had mixing desks and home stereos had dials. Turning a dial clockwise to amplify is (from an overhead POV) a left-to-right motion. For a right-handed person with their hand in a neutral position on a mixing desk, "up", "forwards" and "right" gestures are outwards and indicate more/bigger whereas down and left would indicate less. If we were more left-handed, maybe this would have been different.

The left-right amplification motion is present in many day-to-day widgets - your car air-conditioning or your TV remote (visual display), the slider on your toaster, or maybe the reception 'bars' on your cell phone.

Also, a vast number of volume sliders do indicate that left-to-right is an increase - usually with an icon of a triangle, larger at the right. It's hard to imagine this visual cue would be reversed in RTL languages, and I therefore don't think it should be linked too strongly with reading direction.

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    Righty-tighty, lefty-loosey is pretty much a a universal standard. Screws, nuts and bolts are clockwise threaded, clocks go to the right, and so forth. If fact you'd be hard pressed to find a left oriented object.
    – Bill
    Commented Oct 4, 2011 at 23:34
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    @Bill: On valves, such as water faucets (except for mirrored "lever" types and ball valves), counterclockwise is more. This presumably derives from the conventional thread direction, but here looser = more.
    – Kevin Reid
    Commented Oct 5, 2011 at 18:34
  • @Bill flammable gas connection threads (e.g. gas cylinder) are all left-handed (I believe to prevent accidental attachment to the wrong line, e.g. oxygen). Commented Nov 18, 2016 at 2:55
  • @Johnathan - There are exceptions to every rule, for example on water pumps the threading is backwards on the impeller so that the screw will tighten rather tan loosen with movement. But the general rule is "righty-tighty, lefty-losely"
    – Bill
    Commented Nov 18, 2016 at 22:43

When reading from left to right (like most western languages) you advance by going right. You reach further, increasing the distance your eyes travel. I can see why that translates to increasing any amount (volume, brightness, etc.) quite naturally.

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    Good point - in countries where written language goes from right to left is the default the other way round?
    – Rory Alsop
    Commented Oct 4, 2011 at 19:46
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    coming from such a country (Israel) I'd have to say no, actually. But in Hebrew numbers are still written just like in English so maybe that's why we see 0 .. 100 as a natural progression from left to right. Interesting question though.. Commented Oct 6, 2011 at 17:16

The numbers on the x-axis of a graph (or plotter, or oscilloscope etc.) increase from left to right. The sliders on the technical software I write quite deliberately work the same way.


Basic musical instruments like piano or organ, for instance.

Start with any key on the keyboard and the notes go up as you press keys moving to the player's right, they will go lower as the keys are pressed moving to the player's left.

It's the same with an organ, harpsichord, etc. so it's been around for hundreds of years.

  • The asker is referring to a higher volume, not pitch, as you go left to right.
    – Nick T
    Commented Nov 21, 2016 at 5:07

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