I Should Have Known It

Required String Notes:D - G - D - G - B - E

How to Tune from Standard to DGDGBE Tuning (Open G6)

Start in standard tuning (E-A-D-G-B-E) and change 2 of 6 strings to play “I Should Have Known It”:

String	Standard	Target	What to do
String 6	E2	D2	Tune down a whole step
String 5	A2	G2	Tune down a whole step
String 4	D3	D3	Leave as is
String 3	G3	G3	Leave as is
String 2	B3	B3	Leave as is
String 1	E4	E4	Leave as is

Recommended string gauge: .010–.046. Tension stays close to standard, so a regular set works without any setup changes.Ernie Ball Regular Slinky (.010–.046) · affiliate link

Song Overview & Tuning Breakdown

"I Should Have Known It" by Tom Petty is played in DGDGBE Tuning (Open G6) (D - G - D - G - B - E). Starting from standard tuning (E-A-D-G-B-E), you retune 2 of 6 strings: string 6 down to D, string 5 down to G. Overall string tension drops, with the biggest change being 2 semitones down. 16 other songs in our catalog use DGDGBE Tuning (Open G6).

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Tunings Close to DGDGBE Tuning (Open G6)

Already tuned to D - G - D - G - B - E? These tunings are just one small change away.

Drop D Tuning130 songs

D - A - D - G - B - EOnly string 5 differs: A instead of G.

Open G Tuning59 songs

D - G - D - G - B - DOnly string 1 differs: D instead of E.

CGDGBE Tuning19 songs

C - G - D - G - B - EOnly string 6 differs: C instead of D.

Custom Tuning (EGDGBE)6 songs

EGDGBEOnly string 6 differs: E instead of D.

Tom Petty’s Guitar Tunings

Tom Petty plays 1 of 3 songs in our catalog in DGDGBE Tuning (Open G6). Most-used tunings:

DGDGBE Tuning (Open G6)D - G - D - G - B - E1 song
Open A TuningE - A - E - A - C# - E1 song
Custom Tuning (FA#D#G#CF)FA#D#G#CF1 song

Gear for DGDGBE Tuning (Open G6)

Strings and tools that make playing "I Should Have Known It" in DGDGBE Tuning (Open G6) easier.

Ernie Ball Regular Slinky (.010–.046)

Recommended gauge .010–.046. Tension stays close to standard, so a regular set works without any setup changes.

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D'Addario Universal Micro Headstock Tuner

A headstock tuner makes switching in and out of this tuning quick, even on stage or without a mic.

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“I Should Have Known It” Tuning FAQ

What tuning is "I Should Have Known It" by Tom Petty in?

"I Should Have Known It" is played in DGDGBE Tuning (Open G6): D - G - D - G - B - E, from the lowest to the highest string.

How do I tune my guitar to play "I Should Have Known It"?

Start from standard tuning (E-A-D-G-B-E). String 6: tune down a whole step (E2 → D2). String 5: tune down a whole step (A2 → G2). Leave the other strings as they are.