Armour Class (AC) Conversion Between OSR/D&D Systems

In this table, you will find the AC values ​​of different editions of Dungeons & Dragons and the most important retroclones/OSR games.

B/X D&D = Dungeons & Dragons Basic/Expert sets. AD&D = Advanced Dungeons & Dragons. BFRPG = Basic Fantasy RPG. S&W = Swords & Wizardry*. BXE = B/X Essentials (name changed to Old-School Essentials). LL = Labyrinth Lord. AS&SH = Astonishing Swordsmen & Sorcerers of Hyperborea. OSRIC = Old School Reference and Index Compilation. DCC = Dungeon Crawl Classics. 1E = Advanced Dungeons & Dragons First Edition. 5E = D&D Fifth Edition. LotFP = Lamentations of the Flame Princess**.

*S&W uses both the descending and ascending systems. In the ascending system, the base AC is 10, and continues identically to DCC, although the armour types are more similar to 1E.

**LotFP has an AC of 18 as the maximum value. This value can increase if you use plate mail with a shield, you have a high dexterity or get circumstantial bonuses.

BFRPG B/X D&D,
S&W
LL,
AS&SH, BXE
1E,
OSRIC
DCC, 5E, S&W LotFP
11
(no armor)
9
(no armor)
9
(no armor)
10
(no armor)
10
(no armor)
12
(no armor)
12
(shield)
8
(shield)
8
(padded leather)
9
(shield)
11
(shield, padded)
13
(shield)
13
(leather armor)
7
(leather armor)
7
(studded leather)
8
(leather, padded)
12
(leather armor)
14
(leather armor)
14 6
(scale mail)
6
(scale mail)
7
(studded, ring)
13
(studded, hide)
15
15
(chain mail)
5
(chain mail)
5
(chain mail)
6
(scale mail)
14
(scale mail)
16
(chain mail)
16 4
(banded mail)
4
(banded mail)
5
(chain mail)
15
(chainmail)
17
17
(plate mail)
3
(plate mail)
3
(plate mail)
4
(banded armor)
16
(banded mail)
18
(plate armor)
18 2 2 3
(plate mail))
17
(half-plate)
18
19 1 1 2
(field plate)
18
(full plate)
18
20 0
(suit armor)
0 1
(full plate)
19 etc.
21 -1 -1 0 20
22 -2 -2 -1 21
23 -3 -3 -2 22
24 -4 -4 -3 23
25 -5 -5 -4 24
26 -6 -6 -5 25

Compatibility between most OSR games, and retro-compatibility with classic D&D editions, are two of their biggest attractions. If you don’t have a manual, you can use the adventures published for it with another system; conversion is easy and in most cases it can be done without prior preparation.

Author:

Jorge Jaramillo Villarruel nació y vive en Ciudad de México. Ha colaborado en BOLIVIA TRES PUNTO CERO con ficciones quincenales. Editó la revista digital TRANSEÚNTES, en el INJUVE DF. Ha publicado cuentos, crónicas y ensayos en revistas digitales e impresas. Fue finalista en el Rodeo de Palabras 2007, en el periódico EXPRESO de Sonora y segundo lugar en el XIV Concurso Internacional de Cuento Navideño, Súbito, Breve y Electrónico (2011) de editorial Ficticia. Participó en la ANTOLOGÍA MEXICANA DEL ZOMBIE y en LOVECRAFT: UN TRIBUTO MEXICANO, publicados por El Under Ediciones. Fue invitado a participar en ALEBRIJE DE PALABRAS: ESCRITORES MEXICANOS EN BREVE, antología editada por la Benemérita Universidad Autónoma de Puebla (México), institución que también publicó su primera novela, LOS ELEFANTES SON CONTAGIOSOS, ganadora de la convocatoria para la colección ‘René Avilés Fabila’ 2014. Aparece en la antología THE BEST OF SPANISH STEAMPUNK, de la editorial Nevsky (España). Sus cuentos son materia curricular en la asignatura de “Lengua española, arte y literatura”, en el Tecnológico de Monterrey, campus Toluca.

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