Martin Style 18 Guitar Models:
Martin D-18, OM-18, 000-18, 00-18, 0-18

Description: Martin D-18, OM-18, OOO-18, OO-18, O-18 style flat top guitars
Available: 1857 to present.
Collectibility Rating: 1934-1944 OOO-18, 0M-18 and D-18 sizes: B, 1945-1965 OOO-18 and D-18 sizes: C, 1965-1969 OOO-18 and D-18 sizes: D. Smaller body sizes subtract a full letter grade.
General Comments: The Style 18 Martin guitar (D-18, OM-18, 000-18, 00-18, 0-18) is a spruce top, mahogany body Martin guitar that has been the mainstream of the Martin guitar line since the mid-1800s. Awesome sound, many famous stars have used the Style 18 as their main guitar (for example Elvis Presley used a WW2-time Martin D-18 guitar as his main instrument during much of the 1950s). The Martin D-18 and other style 18 models are not the fanciest Martin model, but it's a good basic spruce-top, mahogany body guitar with a fantastic sound. A good bang for the buck, hence Martin sold a lot of them through their history. The "18" portion of the model indicates the style of the guitar. The letters before the "18" indicate the body size (0-18 being the smallest, 00-18 being larger, OM-18 and 000-18 being larger still, and D-18 being the largest). The models D-18 and OM-18 and 000-18 are regarded as "the best" sizes as applicable to today's musical styles. The OM-18 (1930-1933) is particularly interesting because of it's early design with modern features. Note there are some other style 18 models too like the OO-18G (gut string, 1936-1962), OO-18C (classical, 1962-1976), and the coolest OO-18K (Koa wood, 1918-1925). The gut and classical models are not really desirable. The 00-18k though is a really pretty model. Note when refering to the number of "frets", this means the number of frets clear of the body (not the total number of actual frets). This will be either 12 or 14 frets clear of the body.

Model     Years
-----     ---------
1-18      1899-1927
2-18      1898-1900, 1902-1925, 1929, 1938
5-18      1919-1981, 1898-1917
O-18      1898-1983, 1985-present
O-18K     1918-1935
O-18T     1929-present
OO-18     1898-1981
OO-18G    1936-1962
OO-18C    1962-1976
OO-18K    1918-1925
OOO-18    1923-present, 1911-1922
OM-18     1930-1933
D-18      1931-present

Here's a list of the body sizes (because before October 1930 the body style and size was not stamped into the neck block above the serial number, so the body size and style number are hard to determine on pre 10/30 models):

Size   Frets   Width     Depth    Length    Year Introduced/Notes
----   -----   -----     -----    ------    ---------------------
O      12      13 1/2    4 3/16   19 1/8    1852
O      14      13 1/2    4 1/4    18 3/8    1932 (first year for 14 frets)
OO     12      14 1/8    4 1/16   19 5/8    1877
OO     14      14 5/16   4 1/8    18 7/8    1934 (first year for 14 frets)
OOO    12      15        4 1/16   20 7/16   1902
OOO    14      15        4 1/8    19 3/8    1934 (first year for 14 frets)
OM     14      15        4 1/8    19 3/8    1929 (discontinued 1934)
D      12      15 5/8    4 3/4    20 15/16  1931 (available 1916 from Ditson)
D      14      15 5/8    4 7/8    20        1934

If you need to figure out the exact year and body size of your Martin style 18 guitar, use the serial and style/size numbers. This is stamped inside the body's sound hole on the neck block. See the Martin Serial Number Info web page for help determining the exact year.

If you have a vintage Martin style 18 (D-18, OM-18, 000-18, etc.) guitar for sale, please contact me at

    Originally introduced with rosewood back and sides, the Style 18 since 1917 has Mahogony back and sides, no volute neck, black bridge pins. First listed in 1857.

    1857 Martin Style 18 guitar introduction specs:

    • Ebony fingerboard.
    • No fingerboard inlays.
    • Rosewood back and sides.

    1898 Martin Style 18 guitar specs:

    • 0-18, 00-18 introduced, unbound ebony fingerboard, rectangle bridge.

    1902 Martin Style 18 guitar specs:

    • Small dot fingerboard markers at 5th, 7th and 9th frets.
    • Soundhole inlay of nine alternating black and white rings, inbetween two single black rings.
    • Black back stripe.

    1917 Martin Style 18 guitar specs:

    • Mahogany back and sides.

    1918 Martin Style 18 guitar specs:

    • Rosewood binding on top and back.

    1923 Martin Style 18 guitar specs:

    • Most style 18 models braced for steel strings.

    1924 Martin Style 18 guitar specs:

    • 000-18 has 25.4" scale length.

    1930 Martin Style 18 guitar specs:

    • OM-18 introduced with small pickguard, belly bridge, black bridge pins and black backstripe, 14 fret neck, 25.4" scale (longer than 000-18), no peghead decal, Grover "planetary" banjo tuners.

    1931 Martin Style 18 guitar specs:

    • OM-18 has larger pickguard, normal right angle tuners, decal peghead logo.
    • 00-18 now uses a belly bridge (0-18 still has a rectangle bridge).

    1932 Martin Style 18 guitar specs:

    • Tortoise pickguard.
    • 5-ply top binding with black plastic outer layer.
    • Single ply black plastic back binding.
    • Small graduated dot fingerboard inlays from the 5th fret to the 15th fret. The 5th fret inlay is the largest (1/4"), with the 7th fret being slightly smaller, and the 9th, 12th and 15th being all the same size (smaller still). The size of the dots goes from .25" to .20 to .15" in diameter at the 9th thru 15th frets.
    • D-18 Introduced with a 12 fret neck, ebony fingerboard, black bridge pins (a total of 29 D-18s were made from 1932 to 1933 with a 12 fret neck).
    • 000-18 replaced by the 0M-18 (only in 1932 & 1933), and 000-18 not available.
    • 0-18 now uses a belly bridge.

    1933 Martin Style 18 guitar specs:

    • OM-18 discontinued in late 1933.

    1934 Martin Style 18 guitar specs:

    • 000-18 reintroduced (replaces OM-18) with 14 frets clear of the body, 24.5" scale reduced from the OM scale of 25.4". Note some Martin 000-18 models from Fall 1934 are "000" (not "OM") and have the longer scale length. For example, Martin 000-18 serial #57553 is long scale, yet Martin 000-18 #57918 is short scale.
    • D-18 now has a 14 fret neck.
    • Shaded sunburst top optional.

    1935 Martin Style 18 guitar specs:

    • 0-18, 00-18, 000-18: some with rosewood fingerboard.

    1936 Martin Style 18 guitar specs:

    • 0-18, 00-18, 000-18: most with rosewood fingerboard (still some with ebony).
    • Tortoise outer body binding used on some Style 18 models. Body size 000-18 and smaller used tortoise first, with D-18 models getting tortoise outer body binding around 1938. But either black or tortoise can be seen in 1936-1938 on Style 18 models.

    1939 Martin Style 18 guitar specs:

    • All Martin models change the neck nut width from 1 3/4" to 1 11/16" around serial number 72740.
    • Top X bracing changes from "advance" or "forward bracing" to "rear shifted" bracing.

    1940 Martin Style 18 guitar specs:

    • 0-18, OO-18, 000-18: rosewood fingerboard standard (D-18 still uses ebony).

    Late 1944 Martin Style 18 guitar specs:

    • Heavy bracing replaces scalloped bracing.

    1945 Style 18 specs:

    • Some models have rosewood back binding instead of tortoise celluloid, due to wartime shortages.
    • Either Sitka or Adirondack red spruce top (Sitka is prevelant on D18's for 1945).

    1946 Martin Style 18 specs:

    • Larger uniform sized dot fingerboard inlays replace small graduated dots.
    • Sometimes Adirondack red spruce multi-piece tops seen in this year on 000 models.
    • Sitka spruce top (darker than the 1945 and prior Adirondack spruce).

    1947 Martin Style 18 guitar specs:

    • Rosewood fingerboard replaces ebony on D-18.
    • Large graduated sized dot fingerboard inlays (larger than the pre-1946 graduated dots) at 5th, 7th, 9th, 12th and 15th frets. Dot sizes start at .30" to .25" to .20" in diameter at the 9th thru 15th frets.

    1966 Martin Style 18 guitar specs:

    • Body binding changes to black (instead of tortoise).

    1967 Martin Style 18 guitar specs:

    • Black pickguard (instead of tortoise).

    1972 Martin Style 18 guitar specs:

    • Brazilian rosewood no longer seen for fingerboards on sytle 18 models.

    1996: Martin 0-18, 00-18 guitars discontinued.

1930 Martin 0M-18 guitar with Grover "banjo" planetary tuners.
I was supposed to buy this guitar from a guy in the NW, but at
the last second he backed out of the deal. *sigh*.

1936 Martin 000-18 guitar, non-original case.
A really nice guitar and all original. I love how this guitar plays and sounds.

1937 Martin D-18 guitar, sunburst, original case.

1938 Martin 000-18 guitar, non-original case.
Another really nice guitar and all original (except for the bridge pins, which should be black).

1941 Martin D-18 guitar, original hard case.
The war-time Martins are awesome. Though I guess you could consider
this one "pre-war" (anything before 1942 is considered "pre-war", as
America's entrance into WW2 was December 1941). Very loud and smooth sounding.

Another 1941 Martin D-18 guitar, original hard case.
The twin to the above 1941 Martin D-18 guitar. What's better than
a 1941 Martin D-18? Another 1941 Martin D-18 guitar!

An original 1946 Martin D-18 guitar. This has a Sitka spruce top (supposedly darker
than the 1945 and prior Adirondack spruce, but it sure doesn't look like it).
Still retains an ebony fingerboard and bridge (this changed to rosewood in 1947).
Tuners are war-era plastic button style. The dark marks on the top were from a
guitar strap laying on top of the guitar for years inside the case.

An original 1946 Martin 000-18 guitar. Notice the 4-piece Adirondack spruce top. Martin was still
having problems getting spruce just after WW2, and was trying to use up all their Adirondack
red spruce as they changed to Sitka spruce.) The Tuners have metal bushings but plastic buttons
(plastic buttons again are a WW2-era feature.)

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