BOSS TU-3 Chromatic Tuner Pedal

Pedal: The BOSS TU-3 is a compact chromatic floor tuner for guitar and bass, with a 21-segment LED meter, several tuning modes and a stompbox-style body. Its meter has a brightness control, and the listing claims accuracy to within one cent. The specifications include conflicting dimensions and power details, so check those before choosing a power setup.

At a glance

Chromatic and guitar/bass modes include string-number tuning, with support listed for 7-string guitars and 6-string basses.
Guitar Flat mode supports drop tunings up to six semitones below standard pitch.
The 21-segment LED meter includes brightness control. The listing also describes a high-brightness mode for outdoor glare.
Accu-Pitch Sign provides visual confirmation when tuning is complete.

Price

$125.95Save 10%

Reference price: ~~$139.99~~

Price checked: Nov 12, 2026

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Pros and cons

Pros

Multiple tuning modes cover chromatic tuning, string-number selection and drop tunings up to six semitones below standard pitch.
A brightness-adjustable LED meter and visual tuning-complete indicator can help make status easier to read at a glance.
Customer feedback describes the pedal as easy to use and well built.

Technical specifications

10 specifications

Identity
Brand	BOSS
Model	TU3

Tuning
Meter	21-segment LED meter with brightness control
Claimed accuracy	Accurate to +/- one cent
Tuning modes	Chromatic and Guitar/Bass mode (tune by string number, with support for 7-string guitars and 6-string basses)
Flat tuning	Flat tuning is supported with Guitar Flat mode, which allows for “drop” tunings up to six semitones below standard pitch
Tuning confirmation	Accu-Pitch Sign function provides visual verification when tuning is complete

Power and battery
Power configuration	Corded Electric

Dimensions and installation
Dimensions listed	10.2 x 7.6 x 15.2 centimetres
Weight listed	390 g

What to know before buying

Listing details to confirm

Listing details conflict or remain unconfirmed: dimensions are listed as both 9.8L x 6.7W x 15.2H centimetres and 10.2 x 7.6 x 15.2 centimetres. Power is listed as Corded Electric, while the details also state that 1 D batteries are required. Confirm the selected unit's measurements and intended power method before buying.

Who is it for?

A good fit for

Guitarists and bassists who want a floor tuner with chromatic and string-number modes.
Players using supported 7-string guitars, 6-string basses or drop tunings up to six semitones below standard pitch.
Stage users who want a visible meter and visual confirmation when tuning is complete.

Less suited to

Buyers who need confirmed dimensions or a clearly documented power method without checking the listing first.
Players looking for an effects pedal rather than a tuner. The listing's audio-effects field is not supported by the described tuning features.

BOSS TU-3 Chromatic Tuner Pedal · photo 2 — Additional product photo 2

Customer reviews on Amazon

4.6 / 5 · 2,450 ratings

5 stars81%81%
4 stars10%10%
3 stars3%3%
2 stars1%1%
1 star5%5%

Customer feedback is strongly positive about build quality, tuning performance, accuracy, durability and ease of use. That aligns with the listed stage-oriented meter and tuning modes, though customer impressions do not independently verify the claimed one-cent accuracy. The aggregate ratings are mostly five-star, but a smaller share are low ratings, so experiences are not uniformly positive.

Positive themes

Customers describe the pedal as well built and easy to use.
Customers report satisfaction with its tuning performance, accuracy and durability.

Frequently asked questions

Can the TU-3 tune bass as well as guitar?

Yes. The listing describes Guitar/Bass mode and support for 6-string basses, as well as 7-string guitars.

How far does its flat-tuning mode go?

The listed Guitar Flat mode supports drop tunings up to six semitones below standard pitch.

What indicates that tuning is complete?

The Accu-Pitch Sign function provides visual verification when tuning is complete.

What power source should I plan for?

The listing identifies Corded Electric power but also says 1 D batteries are required. Those details conflict, so confirm the intended power method for the selected unit.