A Guide to Identifying Common Acoustic Guitar Shapes and Sizes
Certain instruments, like those in the violin family, tend to be standardized, with consistent sets of measurements and materials that have remained nearly unchanged for over 300 years. The relatively young steel-string guitar, on the other hand, is wildly diverse. It appears in many different sizes and shapes, which work for a wide range of styles and approaches.
Today’s guitar sizes developed as the instrument’s popularity grew and playing opportunities expanded in the early 20th century. Players sought more volume as the instrument moved from the parlor to clubs and bars, and guitar makers responded by developing broader and deeper guitars, ultimately leading to large models like the dreadnought and the jumbo.
The result of this development of acoustic guitar sizes leaves today’s players with a tremendous selection of shapes and sizes to choose from. Volume is no longer an issue—at least not for players who use pickups and microphones—thanks to advancements in amplification. Each size seems to offer players something unique, and these different strengths are one reason why many guitarists cannot be satisfied with just one instrument.
This guide hopes to give you a general understanding of what the different guitar sizes are and what they may offer. It is organized using the most common styles: those pioneered by Martin and Gibson from the mid-1800s to the 1940s, which have been the benchmark for so many other makers big and small. Keep in mind that in order to find the size—or sizes!—that will work best for you, there’s no substitute for trying out the entire range.
The Mighty Dreadnought
Martin’s dreadnought is an icon, the acoustic guitar world’s most identifiable—and copied—shape. The dreadnought emerged in 1916 as a large-bodied 12-fret guitar with a wide waist and was made for Ditson, a prominent music publisher and dealer based in New York and Boston. The Ditson dreadnaught [Martin used this spelling until the early 1960s, when it changed it to dreadnought —Ed.] was built for steel strings but used a fan bracing pattern until that spec was switched to X-bracing in 1921.
Ditson was sold in 1930, and the following year Martin began producing the dreadnought under its own name. The newly named D-18 and D-28 both debuted in early 1931. But the dread didn’t start to take off until 1934, when Martin shortened the body—giving its shoulders a squared-off look and moving the bridge a couple of frets closer to the neck block—as well as added a longer, 14-fret neck. This is the basic form that the dread has had ever since.
At 15-5/8 inches across the lower bout and with a body that tapers from 4-7/8 inches deep at the endpin to 3-7/8 at the neck, the 14-fret Martin dreadnought is a large guitar. The instrument has plenty of power, volume, and bass response. While early adopters used the dreadnought in string band music, as it would not be drowned out by fiddles and banjos, it also found a home in rock, country, gospel, and nearly every style of popular music.
The dreadnought’s initial appeal was its great power and bass response—ideal for country and bluegrass accompaniment. It became especially prized by flatpickers for the presence it lends to single-note lines, bass runs, and strumming. Tony Rice was known for using an old, heavily modified D-28 previously owned by Clarence White, as well as his Santa Cruz Guitar Company signature models, while young players like Billy Strings and Molly Tuttle have their Preston Thompson signature editions. But that’s not to say that the dreadnought does not work well for fingerstyle play—for instance, Michael Hedges used a 1971 Martin D-28 to excellent effect with this approach.
For many decades, a majority of guitar makers have offered at least one dreadnought—if not many. A search for current D-sized models on Martin’s website yields dozens of results, including both modern versions and historical re-creations, from the entry-level D-X1E to the D-28 Modern Deluxe to the D-45S Authentic 1936 Aged. Larger companies like Alvarez, Takamine, and Yamaha make affordable variations on the dreadnought platform, and Guild also has a long history with the body size (see a review of the A-20 Marley on page 74). Boutique builders like Bourgeois, Collings, and Santa Cruz offer their finely crafted interpretations with a range of wood and trim options. While most new dreadnoughts have 14-fret necks, there are still some 12-fret versions being produced, like those in Collings’ DS series and Santa Cruz’s D-12 model.
In 1934, Gibson responded to Martin’s dreadnought with a big guitar called the Jumbo. Though it was produced for only two years, this guitar became the basis for a bunch of other large-bodied models, like the Advanced Jumbo; the J-50; Gibson’s most influential flattop, the J-45; and others. The Jumbo and J-45 have short scale length fretboards (24.75-inch), while the Advanced Jumbo has a longer scale, 25.5 (slightly more than Martin’s 25.4). All of these models have dreadnought-sized bodies, but with round shoulders compared to Martin’s characteristic squared-off design. Gibson would also eventually offer square-shouldered dreadnoughts, like the Hummingbird and the Dove.
The best Gibson slope-shouldered dreadnoughts are characterized by their loudness, tonal balance, and clarity. Among the many singer-songwriters who have relied on the J-45, affectionately known as the Workhorse, or one of its variants are Bob Dylan, James Taylor, Gillian Welch, and Lucinda Williams.
Though not quite as common as its square-shouldered counterpart, the slope-shouldered dreadnought design has long been an inspiration for other makers. With models like the E10SS and E20SS, Eastman offers affordable options, while Taylor puts a contemporary spin on the slope-shouldered dread through its recent Grand Pacific body shape with V-Class bracing. At the same time, Collings’ CJ-45 T has more of an old-school vibe.
The Orchestra Model
The second most influential body size is the OM, or orchestra model. Its body is a bit smaller than a dreadnought, with a 15-inch-wide lower bout and a body depth that tapers from 4-1/8 inches to 3-1/4 inches. This model was developed in 1929, when the bandleader, banjoist, and guitarist Perry Bechtel asked Martin to build him a guitar with a longer neck. Up until that point, every Martin had a neck-to-body junction at the 12th fret, like a classical guitar. The company made Bechtel a guitar with a 14-fret neck, moving the position of the bridge to accommodate this new design, and the OM—essentially a 14-fret version of the 12-fret 000 size first seen in 1902—was born. (Note that, somewhat confusingly, the term OM was also used on other 14-fret models of the early and mid-1930s.)
Around 1934, the guitar was separated into two models that shared the same body size: the OM, with a 25.4-inch scale length fretboard, and the 000, with a 24.9-inch scale length. Both OMs and 000s are known for producing rich lows and sparkling highs that deliver great all-around tone for just about every type of music. The longer-scale OM is characterized by its outstanding responsiveness, brilliance, and projection, while the 000 may have a slightly warmer, mellower sound, plus its shorter scale makes string-bending easier.
Many fingerstyle players, including Laurence Juber and Eric Schoenberg, consider the OM/000 to be the ultimate fingerstyle guitar, but it’s terrific for flatpicking, too. Eric Clapton relied on a 1939 000-42 and a 1966 000-28 (modified with style-45 appointments) for his 1992 Unplugged performance and album, and his various Martin signature models have been enormously popular. Grant Gordy has used a mid-1940s 000-18 to excellent effect, and Julian Lage recorded his solo acoustic album, World’s Fair, using a 1939 000-18. Lage’s 000-18, incidentally, was the inspiration for his signature Collings OM-1 JL (reviewed in the March/April 2018 issue), whose neck profile takes it shape from Lage’s Martin.
Collings is, of course, but one of many makers who have long offered a selection of OM and 000 variations in their lineups. The Martin website currently lists more than two dozen different models, from the affordable OMC-X1E to the ornately appointed 000-42 and OM-42; the OM-28 remains the maker’s most popular example. Companies like Guild offer smartly priced modern OMs, while OMs/000s by small shops like Bourgeois and Santa Cruz and luthiers like Julius Borges and John Slobod offer very fine interpretations.
At the same time, some makers offer their own body sizes similar to the OM. For instance, Taylor’s popular Grand Concert (not to be confused with Martin’s size of the same name, detailed in the next section) also has a 15-inch lower bout, like a 000, along with a short scale length, 24-7/8 inches. The GC’s relatively compact dimensions are great for an intimate, focused sound that works especially well for recording fingerstyle playing or punchy strumming.
The Biggest Boxes
In 1938, Gibson released its Super Jumbo (later called the SJ-200 and then the J-200), a huge, 17-inch-wide guitar with a narrow waist and a 4-7/8-inch-deep body that was large enough to make nearly any musician look tiny. Later, in 1951, Gibson introduced the J-185—a scaled-down version of the SJ, with the same body depth but a 16-inch lower bout (the same shape as the maker’s 16-inch archtops). These two body sizes are now known as jumbo and small jumbo, respectively. With distinct note separation, crisp trebles, robust bass, and scooped midrange, jumbos became popular with singing cowboys, ragtime guitarists, and many singer/songwriters from Little Jimmie Dickens to Emmylou Harris, Reverend Gary Davis, and George Harrison.
Though not as popular these days as smaller guitars, there are still plenty of jumbo and small jumbo models being made. Gibson offers versions in all of its different acoustic lines, as do Gretsch, Guild, Yamaha, and other companies. Some builders, like Lowden, have taken the jumbo in new directions. Lowden’s O (Original) style is especially noted for its dynamic ability—or headroom—to project delicate passages as clearly as aggressive strumming and big bass and overtones. Taylor’s biggest model, the 16-1/4-wide Grand Symphony, is another notable variation on the jumbo platform.
Martin’s M size developed when a few luthiers converted examples of Martin’s unpopular F-series archtop to flattop, the depth of an OM/000 but an inch wider (16 inches) at the lower bout. In 1977 Martin began producing the new grand auditorium guitars as the M-38 and M-36, later renaming them 0000 for a few years before reverting to the M series seen today. This body size is known for a complex, balanced sound for strumming and fingerstyle playing that makes a big sound without the bulk of a dreadnought.
J series Martin guitars took the body of an M and gave it the depth of a dreadnought. This jumbo style debuted in 1985 and was immediately popular with rhythm players, who liked the guitar’s powerful response, significant volume, and separation between the bass and treble frequencies, without the boominess that is sometimes associated with dreadnoughts. Martin currently offers only one example of each jumbo guitar style—the M-36 and the J-40—but a dealer like Gruhn Guitars offers custom-ordered Martin 0000s. Though the size is less common than others, makers like John Greven, Wayne Henderson, and Santa Cruz have all made 0000 variations.
Generally speaking, smaller guitars fell out of favor as new and bigger models gave players the volume they needed to compete with other instruments in ensemble settings. But in the last few decades, as amplification technology has greatly improved and volume from instruments has generally become less of a concern, guitarists have been increasingly drawn toward more compact instruments like 00s.
At either 14-1/8 inches (12-fret version) or 14-5/6 (14-fret) across the lower bout with a depth of 4-1/8 inches, Martin’s 00 has a body that is close in size to a classical guitar. Also known as the grand concert model, it typically has a warm, present bass response, perfect for fingerstyle play and chordal strumming alike. Though it’s smaller than an OM or dreadnought, the 00 tends to actually be quite loud. It creates a very balanced tone, with an even level of bass and treble on either side of a full midrange. In both its 12- and 14-fret versions, it’s remained a favorite for fingerstyle blues and ragtime players.
Gibson’s L series (L-00, L-0, L-1, L-2, etc.) of flattops—not to be confused with the L designation used for archtops—started off in 1926 as a 12-fret platform with a 13-1/2-inch-wide body and a roundish lower bout. This size eventually received a 14-fret neck, as well as a 14-3/4-inch-wide and 4-5/16-inch-deep body with a squarer lower bout and narrow upper bout. With a warm, woody sound and good projection, the L-series Gibsons became a favorite of players such as Robert Johnson, Woody Guthrie, and more recently, Joe Henry. In a similar size class, the slightly smaller body shape for Gibson’s LG series and B-25, with a 14-1/8-inch lower bout, tends to produce a sweet and balanced tone.
Martin and Gibson currently make plenty of variations on their 00, L, and LG series of guitars, some updated for the modern player and others exacting re-creations of historic models. And these body sizes have inspired lots of newer designs as well. Santa Cruz’s Eric Skye signature model, for instance, is based on Martin’s 00 12-fret size, but with a deeper body, while Collings’ most recent 00 series is patterned after the 14-fret version. Waterloo’s flagship WL-14 has a body close to the guitars in Gibson’s L series, as does a model like the Bourgeois L-DBO (reviewed in the January 2017 issue).
The 0, or concert size, is the littlest of Martin’s current full-size guitar sizes. Measuring just 13-1/2 inches across the lower bout and 4-1/4 inches deep, with a 24.9-inch scale length, it’s a small guitar by modern standards. Yet, it has remained in Martin’s line nearly continuously since its introduction in the 19th century, owing to its easy-to-play size and intimate voice. Single 0s often surprise players used to larger guitars with their punchiness and volume. Typically, an 0 produces a balanced sound that excels for fingerstyle playing, recording, and accompaniment.
Concert-sized guitars have been seen in both 12- and 14-fret iterations. Martin currently offers just the latter in its 0-X1E and 0-18 models. At the same time, with its super affordable series of Single 0 guitars, Recording King makes only 12-fret versions, while some high-end companies, like Collings, Huss & Dalton, and Preston Thompson, do offer 0s in both 12- and 14-fret configurations.
In the 19th century, most guitars were much smaller than what we are used to today. Even a large guitar back then would be considered on the smaller side today, but most were what are now call parlor-sized—compact, narrow-waisted instruments with short scale lengths that were meant to be played in the parlor of a home, often by women.
There has been a renewed interest in parlor guitars in recent years, as players have gravitated toward their diminutive size, alluring tones, and responsiveness. Many new parlor models have been introduced at all price points—everything from super affordable examples like Fender’s CP-60 S and Gretsch’s G9500 Jim Dandy to premium-quality modern interpretations like Santa Cruz’s PJ and Lowden’s Wee Lowden. Sting has played a Ditson parlor for some years—it was even seen on his appearance in the recent television series Only Murders in the Building—and Charlie Rauh plays a Collings Parlor 1 in his work as both a sideman and solo guitarist.
Then there are those guitars even smaller than the parlor. From Martin’s Backpacker that was built for roughing it, to Taylor’s Baby and GS Mini, miniaturized guitars have caught on with a wide range of players. Called baby or travel guitars, these instruments give players a more portable instrument than the standard guitar sizes, while also offering often pleasing, sparkling sounds. Baby guitars have shorter scale lengths and less low end, but plenty of presence in the mid and upper frequency ranges that some players love for recording, as well as travel. They might not have the horsepower for your bluegrass jam, but they can be terrific for recording and performing.
The Size 5, which Martin has made since the 1830s, deserves special mention here. A terz guitar tuned a third higher than a standard, it was originally intended not to be a compact offering or children’s instrument but a distinctive voice for ensemble work. Today the Size 5 is often thought of as a travel guitar, and some players prefer its diminutive size for touring—for instance, the country singer Marty Robbins used a Martin Style 5-18 as his main stage guitar.
Why Have Just One?
One of the things about the guitar that makes it so popular is that it is such a versatile instrument, as seen in its many different body shapes and applications. And it explains, at least partly, why so many of us guitarists cannot settle for just one instrument. We all change, and players may find themselves selecting larger instruments for bass-heavy boom that’s important for live performances with bands, or a smaller guitar for playing at home or for when reaching around a dreadnought or jumbo isn’t as easy on aging shoulders as it once was. If you ever get the chance to try different-sized guitars from the same maker, you’ll quickly feel and hear the distinctions yourself. And, if you do, you may find yourself inspired by something different.
Some acoustic guitars feature a cutaway, an area on the upper treble bout that’s removed to allow easier access to the guitar’s highest notes. Cutaways come in many shapes, with Gibson’s rounded Venetian and pointed Florentine versions being two of the best known. Many contemporary makers have adopted a Maccaferri-style cutaway, and Martin has recently pushed the bar with the cutaway and neck-heel design of its SC-13E guitar.
While a cutaway might be beneficial for soloing, some speculate that removing a portion of the instrument’s vibrating top and body cavity has a negative tonal impact. Eric Schoenberg of Schoenberg Guitars says you can’t really know if a cutaway has a positive or negative effect. “It’s a moot point,” he says from his small, charming shop in a historic building in Tiburon, California. “Every guitar is so different—how can you compare? I’ve heard tons of guitars with cutaways that sound incredible and tons of guitars without cutaways that sound great.” Whether you opt for the more traditional look of a full-bodied guitar, or the sleek look of a cutaway may depend on your needs as a soloist or your taste in how a guitar looks, over the sound.
Carving Out a Niche
In 1923 Gibson introduced the L-5, an innovative guitar whose design was inspired by the violin family—a 16-inch-wide body with a carved, arched spruce top and maple back and sides (birch was used in the earliest examples), twin tone bars, f-holes, floating bridge, trapeze tailpiece, and 14-fret neck.
By the early 1930s, with the advent of the big band, archtops began to grow larger. Gibson introduced its 17-inch L-series models in 1935, as well as the 18-inch Super 400 that same year. Competitors like Epiphone, D’Angelico, and Stromberg followed suit, with Stromberg making guitars as wide as 19 inches in the Master 300 and Master 400 models.
As opposed to model names and numbers, archtop bodies are generally indentified by their lower bout width. The most common sizes are 16, 17, and 18 inches, though some makers, like Maegan Wells, often build smaller bodies. Generally speaking, archtops offer punchier and more percussive sounds than their flattop counterparts. And while the larger models can be great for big-band strumming, many players prefer the 16-inch size for its tonal balance and playing comfort.
Though long associated with jazz—the pioneer Eddie Lang was an early adopter of the L-5—archtops are actually quite versatile and work well in other settings. Most notably, they can be heard in rootsy American styles, as evidenced in the work of musicians like Maybelle Carter, who for decades played her 1928 L-5, and Dave Rawlings, who has been known to use a small-bodied 1935 Epiphone Olympic, as well as a 1959 D’Angelico Excel.
Special thanks to George Gruhn, proprietor of Gruhn Guitars, writer, and historian, for his consultation on some of the historical aspects of this feature.
This article originally appeared in the March/April 2022 issue of Acoustic Guitar magazine.