The different tuning types

Before starting, small precision: the following tunings are read from left to right, each letter corresponds to a string (the biggest is on the left, the thinnest on the right).

Main types of tunings

The standard tuning

This is the one used by a very large majority of guitarists, everybody knows it, so we will not dwell on it.
Tuning in "EADGBe". Widely used in popular songs.
 

One tone lower tuning

It is widely used too (Guns N 'Roses, Ben Harper, etc...) Each string is tuned one tone lower compared to the standard tuning (EADGBe), which will give us: DGCFAd.

We get a rounder sound with more depth.

The Open E tuning without third

Widely used by bluesmen. It is built with the root note (E) and fifth (B), without the third (G #).
This gives: E - B - E - E - B - e

The Open C tuning without third

Is obtained by tuning the strings lower by respectively: 2 tones - 1 tone - 1 tone- 4 tones - 2 tones - 2 tones (compared to the standard tuning)
Which gives: C - G - C - C - G - c

This tuning is much rarer.

The Open D tuning without third

The tuning is: D - A - D - D - A - d

The Celtic tuning (Open Dsus4)

This tuning is used in Celtic music to imitate the sound of bagpipes. The A and high D strings are the so-called resonant strings. This tuning is also used for the shining sound it produces.
It is obtained as follows: DADGAD

The Drop D tuning

It's a tuning we often meet in metal or rock.

Here, there is only one change compared to the standard tuning: we lower the E string of one tone to get a D
In fact the tuning is as follows: D - A - D - G - B - E (RE - LA - RE - SOL - SI - mi)

This tuning gives you a heavier sound.

There also exists the Double Drop D, which is similar to the Drop D tuning, the difference being that the high E string is also lowered of a tone (which gives: D - A - D - G - B - d).

Update V5: If you want to discover less known tunings or more exotic ones use our guitar tuning tool.