Mike Nelson Guitar Lessons

Guitar Fretboard Navigation: Cross-String Interval Relationships (Part 2)

Master the practical techniques for finding notes and intervals across guitar strings

📖 Part 2 of 2: This builds on the theoretical foundation from Part 1: Why Strings Are Tuned This Way. Start there if you want to understand the "why" behind these techniques.

Published: June 27, 2025

📚 Choose Your Learning Approach

The detailed mathematical analysis below is completely optional. Everyone makes fretboard connections differently, and it can take time for these relationships to click.

Some players learn best through repetition and muscle memory, others through visual patterns, and others by understanding the mathematical relationships. All approaches are equally valid.

Remember: The more you understand about how the fretboard works, the easier learning becomes - but you don't need to master everything at once. Take what helps you and leave the rest for later.

🎸 For Beginners: Understanding Cross-String Relationships

Here's the key insight: Apart from G to B strings, all other guitar strings are tuned exactly 5 half-steps apart.

🔍 Try This Exercise:

Find the note A on the 5th fret of the low E string. Notice that the exact same note (sounds identical) is found on the string below it, but 5 frets back at fret 0 (the open A string).

💡 The Handy Tip:

If you have a starting point (let's call it the root), and you move up to a note on a higher fret on that same string, you can find that same note on the string below by using this simple calculation:

String Tuning (5) - Frets Moved Up = Frets to Move Back

📝 Example:

  1. Start at the 5th fret on E string (note A)
  2. Move to the 7th fret on E string (note B) → we moved 2 frets up
  3. Calculate: 5 - 2 = 3
  4. Move back 3 frets from the 5th fret on A string: 5 - 3 = 2nd fret
  5. Result: Note B is found on the 2nd fret of the A string

🎯 Why this works: This calculation automatically accounts for the 5-fret tuning difference between strings, making it easy to find any note on adjacent strings without memorizing the entire fretboard.

Cross-String Interval Relationships

🎯 Finding the Same Note on Adjacent Strings

The same note can be found 5 frets back on the next lower string (except G to B, which is 4 frets back).

Example: Finding A on E and A Strings

A:
A
0
•
1
•
2
•
3
•
4
•
5
E:
•
0
•
1
•
2
•
3
•
4
A
5

A on 5th fret E string = A on open A string

The open fret (0) is 5 frets back from the 5th fret

Example: Finding C on E and A Strings

A:
•
0
•
1
•
2
C
3
•
4
•
5
•
6
•
7
•
8
Low E:
•
0
•
1
•
2
•
3
•
4
•
5
•
6
•
7
C
8

C on 8th fret E string = C on 3rd fret A string

The 3rd fret is 5 frets back from the 8th fret

🎯 The Cross-String Interval Formula

Now that you understand how to find the same note on adjacent strings, you can extend this to find any interval:

Example: Major 3rd on E and A Strings

A:
•
0
•
1
•
2
•
3
•
4
•
5
•
6
E
7
M3rd
•
8
•
9
•
10
•
11
•
12
Low E:
•
0
•
1
•
2
•
3
•
4
•
5
•
6
•
7
C
8
Root
•
9
•
10
•
11
E
12
M3rd

Major 3rd Cross-String Formula:

Root: C on 8th fret E string

Same string: Major 3rd (E) = 4 frets higher → 12th fret E string

4 (same string)-5 (string tuning interval)=-1 → 1 fret back

Cross-string: E on 7th fret A string

🧮 How The Cross-String Formula Works

📍 Note: This advanced formula is more comprehensive than the beginner calculation shown above. While the beginner method works great for finding notes when moving up from a reference point, this formula handles any interval relationship and any starting position on the fretboard.

The Formula:

Same-String Interval -String Tuning Interval =Cross-String Position

(All intervals measured in semitones/half steps)

Step by step (Method 1 - Know the interval):

  1. Find your interval on the same string (e.g., major 3rd = 4 frets)
  2. Know your string interval (E-A, A-D, D-G = 5 frets; G-B = 4 frets)
  3. Subtract: 4 - 5 = -1 (negative means go back toward the nut)
  4. Apply to your root note: If root is 8th fret, cross-string is 8 - 1 = 7th fret

Step by step (Method 2 - Use fret numbers):

  1. Find your root fret and interval fret (e.g., root = 8th fret, interval = 12th fret)
  2. Calculate same-string interval: 12 - 8 = 4 frets
  3. Know your string interval (E-A, A-D, D-G = 5 frets; G-B = 4 frets)
  4. Subtract: 4 - 5 = -1 (negative means go back toward the nut)
  5. Apply to your root note: 8th fret - 1 = 7th fret on adjacent string

📝 Written Example:

Goal: Find the major 3rd of C (which is E) on the A string, when C is on the 8th fret E string.

Step 1: Major 3rd = 4 semitones (frets)

Step 2: E-A string interval = 5 semitones

Step 3: 4 - 5 = -1 (go back 1 fret toward nut)

Step 4: 8th fret - 1 = 7th fret → E is on 7th fret A string ✓

Remember: Positive result = move toward bridge, Negative result = move toward nut

🎸 Practical Applications

🎵 Perfect 5th (Power Chords)

E-A strings: 7 - 5 = +2 → 2 frets forward

A-D strings: 7 - 5 = +2 → 2 frets forward

G-B strings: 7 - 4 = +3 → 3 frets forward

This is the classic power chord shape!

🎵 Octaves

E-A strings: 12 - 5 = +7 → 7 frets forward

A-D strings: 12 - 5 = +7 → 7 frets forward

G-B strings: 12 - 4 = +8 → 8 frets forward

Perfect for melodic doubling!

🎵 Major 3rd

E-A strings: 4 - 5 = -1 → 1 fret back

A-D strings: 4 - 5 = -1 → 1 fret back

G-B strings: 4 - 4 = 0 → Same fret

Essential for major chord shapes!

🎵 Perfect 4th

E-A strings: 5 - 5 = 0 → Same fret

A-D strings: 5 - 5 = 0 → Same fret

G-B strings: 5 - 4 = +1 → 1 fret forward

Perfect for sus4 chords and quartal harmony!

Visual Examples: Cross-String Intervals

A-D String Pair: Major 3rd Relationship

1 fret back+4 frets (Major 3rd)=5 frets total
D:
•
0
•
1
E
2
M3rd
•
3
•
4
•
5
•
6
•
7
•
8
•
9
•
10
•
11
•
12
A:
•
0
•
1
•
2
C
3
Root
•
4
•
5
•
6
E
7
M3rd
•
8
•
9
•
10
•
11
•
12

Major 3rd Cross-String Formula:

Root: C on 3rd fret A string

Same string: Major 3rd (E) = 4 frets higher → 7th fret A string

4 (same string)-5 (string tuning interval)=-1 → 1 fret back

Cross-string: E on 2nd fret D string

G-B String Pair: Major 3rd Relationship

0 fret back+4 frets (Major 3rd)=4 frets total
B:
•
3
•
4
E
5
M3rd
•
6
•
7
•
8
•
9
•
10
•
11
•
12
•
13
•
14
•
15
G:
•
3
•
4
C
5
Root
•
6
•
7
•
8
E
9
M3rd
•
10
•
11
•
12
•
13
•
14
•
15

Major 3rd Cross-String Formula:

Root: C on 5th fret G string

Same string: Major 3rd (E) = 4 frets higher → 9th fret G string

4 (same string)-4 (string tuning)=0 → Same fret

Cross-string: E on 5th fret B string

💡 Why This Matters

These relationships help you understand practical ways of finding notes on adjacent strings. Start with the simple "5 frets back" rule for the same note, then use the interval formula when you need different intervals. Instead of memorizing every note position, you can calculate where notes and intervals appear across string pairs.

🔗 How the Simple Examples Connect to the Formula

Notice that the initial "same note" examples actually follow the cross-string interval formula too! When finding the same note on adjacent strings, the same-string interval is 0 frets:

A on E and A strings:

Same-string interval = 0 frets (same note) | String interval = 5 frets

0 - 5 = -5 → Move 5 frets back ✓

C on E and A strings:

Same-string interval = 0 frets (same note) | String interval = 5 frets

0 - 5 = -5 → Move 5 frets back ✓

The formula works for everything - from finding the same note (interval = 0) to finding any musical interval!

These cross-string interval relationships are the foundation of moveable chord shapes and scale patterns. Once you understand how intervals translate across string pairs, you can transpose any musical idea to different positions on the neck.

🔗 Related Articles

Part 1: Why Strings Are Tuned This Way

The theoretical foundation behind guitar tuning and cross-string interval relationships