Neck Relief Gauge Instructions

Neck relief is the slight forward curve of your guitar’s neck under string tension. It's intentional—and necessary. Without that curve, strings can rattle or fret out as they vibrate. With too much curve, your action feels high and sluggish, especially in the middle of the neck.

When your neck relief is dialed in just right, the strings clear the frets cleanly, feel slinky, and ring out with clarity. Relief is especially critical for players who love fast action and smooth bending.

Measuring Neck Relief the Traditional Way

Measuring neck relief is a routine part of guitar and bass maintenance to ensure comfortable playability and minimize fret buzz.

What You’ll Need

Capo
Feeler gauges
Your guitar or bass, in playing position and tuned to pitch

Step 1: Place a Capo on the First Fret

Attach the capo to the first fret to hold down the string and establish a consistent starting point.

Step 2: Press Down the Last Fret (or Where Neck Joins Body)

With your picking hand, press the low E (or high E) string down at the last fret of the neck (or where the neck joins the body, commonly the 17th fret on Fender-style guitars). This uses the string as a straightedge across the frets.

Step 3: Measure the Gap at the 7th or 8th Fret

With your free hand, select a feeler gauge that slides just between the top of the 7th or 8th fret and the bottom of the string without displacing the string's position and measure the gap. This is usually the point of maximum neck relief.

Measuring Neck Relief with the Neck Relief Gauge

The Neck Relief Gauge is a quick and easy way to measure a guitar's neck relief/curvature when adjusting the truss rod. The two feet and the indicator tip sit on the top of the frets, and the indicator reads the amount of bow in the neck. Adjusting the truss rod increases or decreases the amount of this relief in the neck.

Step 1:

Zero the Neck Relief Gauge on an accurate flat plate. Here we are using the surface of a steel jointer. A machinist's granite plate would work well too as long as it is dead flat. To zero the dial indicator, loosen the dial lock (located at the approximate 1 o'clock position of the dial). Turn the knurled dial face so the zero mark is lined up with the needle and re-tighten the dial lock. Note that for most applications, the zero will not be in the 12 o'clock position.

Step 2:

Place the tool on the guitar neck with one end on the first fret and the other end on the twelfth fret. As you adjust the truss rod, the dial will read the relief in thousandths of an inch. A reading of "zero" means that the fret tops are flat (zero relief). The indicator is off-center so it will sit on the fifth or the sixth fret. Adjust the truss rod until you reach the desired relief.

A professional set up:

The guitar is secured in our Neck Jig, and held in the playing position. Now the hands are free to adjust the truss rod while reading the relief.

What’s a Good Neck Relief Measurement?

While there’s no single “perfect” number, here are some good ballpark targets:

Electric Guitars: ~.004"–.008" (up to .010" for heavy pick attack).
Acoustic Guitars: ~.008"–.012" (fingerstyle may like less; heavy strummers more).
Bass Guitars: ~.010"–.015" (longer scale + string excursion).

Use these as starting points, then play‑test. Buzzing or a choked feel in the first or second position? Add relief (loosen rod). Action feeling a little high and the strings are too hard to press down? Reduce relief (tighten rod). Adjust in small 1/8‑turn steps, re‑tune, and let the neck settle before re‑measuring.

Why Not Just Use a Ruler or Feeler Gauge?

You absolutely can—and many players and techs do. But lining up a ruler or feeler gauge under a string that’s already difficult to reach? It’s fiddly, imprecise, and error-prone. The Neck Relief Gauge simplifies everything by providing fast one-handed operation that is easy to read, easy grip, and repeatable accuracy.

Plus, it eliminates variables like eye level or hand pressure that can throw off feeler gauge readings.

Pro Tips for Success

Don’t measure from the last fret. Stick with the area the truss rod actually controls—generally the first fret to the 17th. Measuring from the last fret can give false readings, especially on necks with fallaway or ski-jump issues.
Make sure the neck is stable. After making truss rod adjustments, give the neck a few minutes to settle before taking another reading.
Measure both sides of the neck. Relief can vary slightly between the bass and treble sides. If something feels off while playing, check both.
Humidity matters. Dry air can shrink the wood and cause backbow. High humidity can swell it and increase relief. Check your setup seasonally, especially if your climate shifts dramatically.

Feeling vs. Measuring

We’re all about the feel here at StewMac, but measurement gets you in the zone fast, especially when you’re dialing in a new build, chasing buzz, or trying to match a setup you love. Once you know the numbers that feel good to you, the Neck Relief Gauge helps you hit them every time.

One Tool for Better Setups

Proper neck relief is the foundation of a great-playing instrument. With the Neck Relief Gauge, you’ll set it faster, more accurately, and with confidence. Whether you’re a DIY player or a pro tech, this is one of those little tools that quickly becomes essential on the bench.

Need help adjusting the truss rod after you measure relief? We’ve got full guides and videos to walk you through every step. At StewMac, we’re here to help you build, repair, and play your best guitar—every time.