Guitar tab
Like standard notation, guitar tab consists of a series of horizontal lines forming a staff (or stave). Each line represents one of the instrument's strings, so standard guitar tab has a six-line staff, and bass guitar tab has four lines. Numbers are written on the lines, with each number representing a fret on the instrument. For instance, a number 3 written on the top line of the staff indicates that the player should press down on the high E (top/thin) string (instead of the low E, which is a thicker string) at the third fret. Number 0 denotes an open string.

Various lines, arrows and other symbols are used to denote bends, hammer-ons and so on.

While guitar tab is reasonably standardized, different sheet music publishers adopt different conventions for how to write various things. Songbooks and guitar magazines usually include a legend setting out the convention in use.

The most common form of lute tablature uses the same concept but differs in the details (e.g. it uses letters rather than numbers) - see below.
Guitar tab vs. staff notation
Tab has several advantages over staff notation. Since it is a direct visual representation of the instrument's fretboard, it can often be easier and quicker for the player to interpret. Musicians learning to play the guitar or lute often find tab easier to read, even if they have a strong musical background and are adept at reading staff notation for piano or voice. Simple chords requring the same fret on multiple strings, for example, can appear very advanced written out using standard notation but straightforward using tab.

Another reason why some players prefer tab is the fact that the guitar and lute, like the piano, are 'harmonic' instruments, meaning that multiple notes are played at once; yet there is more complexity to producing a particular pitch than is the case with the piano: to produce, say, middle C, a pianist simply presses the C key, while a guitarist must select the second string, press the string down against the first fret with their left hand, and simultaneously pluck or pick the string with their right hand. An additional potential source of confusion is the fact that many of the notes within the range of a plucked string instrument can be played on several different strings, so for example the middle C discussed above could also be played on the third string at the fifth fret or on the fourth string at the tenth fret. These complexities make the relation between staff notation and playing technique less direct in the case of fretted instruments than in the case of a piano. Tab removes the string/fret ambiguity.

Additionally, because guitar staff notation is written on a single staff (compared to two staves for keyboard music), reading complex chords can take a while for even the most experienced guitarist. Tab does not suffer from this disadvantage.

Another advantage of tab over staff notation is that tab can easily be represented as ASCII tab - a plain-text computer file, using numbers, letters and symbols to construct a slightly crude representation of tab. This characteristic makes it easy to distribute tab electronically, a practice that has become immensely widespread; it is now possible to find tablature for virtually any popular music on the Internet.

Tab does have its disadvantages, however. It is instrument-specific, while standard notation is generic. This limitation means, for instance, that only a guitarist can read tab, while music written in staff notation can be played by any suitable instrument. In a similar vein, since tab notation effectively gives instructions on how to play notes rather than information on how the notes will sound, it can be very difficult to get a feel of the music simply by studying the page without playing it through; this task is easier with staff notation.

Unlike staff notation, tab does not usually include the rhythm of the notes, only their pitch. In practice, this is not much of a limitation. Some players read tab and staff notation in tandem (most published tab is accompanied by staff notation so the two can be compared), while others listen to a recording to get the 'feel' of the music before consulting the tab for instructions on how to play.

In any case, to avoid such difficulties, rhythm can be indicated by notes or note stems written above the tab staff. This is always done in lute tablature, and sometimes in guitar tab, particularly if there is no accompanying notation staff.

The largest disadvantage may be that solely using tablature can keep an individual from focusing on music theory, which derives from a knowledge of the notes themselves, not a recognized predetermined position for playing notes or chords. For a deeper appreciation of the instrument, an understanding of notation can allow an individual to improvise more accurately and freely, or accompany in improvisation through different key changes more clearly and deliberately. A person who has only learned from tab has a tendency to noodle around trying to find the sound they're looking for, rather than recognizing the potential of the notes within the key they find themself in.