In mathematics, the classification of finite simple groups states that every finite simple group is cyclic, or alternating, or in one of 16 families of groups of Lie type, or one of 26 sporadic groups.

The list below gives all finite simple groups, together with their order, the size of the Schur multiplier, the size of the outer automorphism group, usually some small representations, and lists of all duplicates.

Summary

The following table is a complete list of the 18 families of finite simple groups and the 26 sporadic simple groups, along with their orders. Any non-simple members of each family are listed, as well as any members duplicated within a family or between families. (In removing duplicates it is useful to note that no two finite simple groups have the same order, except that the group A₈ = A₃(2) and A₂(4) both have order 20160, and that the group B_n(q) has the same order as C_n(q) for q odd, n > 2. The smallest of the latter pairs of groups are B₃(3) and C₃(3) which both have order 4585351680.)

There is an unfortunate conflict between the notations for the alternating groups A_n and the groups of Lie type A_n(q). Some authors use various different fonts for A_n to distinguish them. In particular, in this article we make the distinction by setting the alternating groups A_n in Roman font and the Lie-type groups A_n(q) in italic.

In what follows, n is a positive integer, and q is a positive power of a prime number p, with the restrictions noted. The notation (a,b) represents the greatest common divisor of the integers a and b.

Class	Family	Order	Exclusions	Duplicates
Cyclic groups	Zp	p prime	None	None
Alternating groups	An n > 4	${\displaystyle {\frac {n!}{2))}$	None	A5 ≃ A1(4) ≃ A1(5) A6 ≃ A1(9) A8 ≃ A3(2)
Classical Chevalley groups	An(q)	${\displaystyle {\frac {q^((\frac {1}{2))n(n+1))){(n+1,q-1)))\prod _{i=1}^{n}\left(q^{i+1}-1\right)}$	A1(2), A1(3)	A1(4) ≃ A1(5) ≃ A5 A1(7) ≃ A2(2) A1(9) ≃ A6 A3(2) ≃ A8
	Bn(q) n > 1	${\displaystyle {\frac {q^{n^{2))}{(2,q-1)))\prod _{i=1}^{n}\left(q^{2i}-1\right)}$	B2(2)	Bn(2m) ≃ Cn(2m) B2(3) ≃ 2A3(22)
	Cn(q) n > 2	${\displaystyle {\frac {q^{n^{2))}{(2,q-1)))\prod _{i=1}^{n}\left(q^{2i}-1\right)}$	None	Cn(2m) ≃ Bn(2m)
	Dn(q) n > 3	${\displaystyle {\frac {q^{n(n-1)}(q^{n}-1)}{(4,q^{n}-1)))\prod _{i=1}^{n-1}\left(q^{2i}-1\right)}$	None	None
Exceptional Chevalley groups	E6(q)	${\displaystyle {\frac {q^{36)){(3,q-1)))\prod _{i\in \{2,5,6,8,9,12\))\left(q^{i}-1\right)}$	None	None
	E7(q)	${\displaystyle {\frac {q^{63)){(2,q-1)))\prod _{i\in \{2,6,8,10,12,14,18\))\left(q^{i}-1\right)}$	None	None
	E8(q)	${\displaystyle q^{120}\prod _{i\in \{2,8,12,14,18,20,24,30\))\left(q^{i}-1\right)}$	None	None
	F4(q)	${\displaystyle q^{24}\prod _{i\in \{2,6,8,12\))\left(q^{i}-1\right)}$	None	None
	G2(q)	${\displaystyle q^{6}\prod _{i\in \{2,6\))\left(q^{i}-1\right)}$	G2(2)	None
Classical Steinberg groups	2An(q2) n > 1	${\displaystyle {\frac {q^((\frac {1}{2))n(n+1))){(n+1,q+1)))\prod _{i=1}^{n}\left(q^{i+1}-(-1)^{i+1}\right)}$	2A2(22)	2A3(22) ≃ B2(3)
	2Dn(q2) n > 3	${\displaystyle {\frac {q^{n(n-1))){(4,q^{n}+1)))\left(q^{n}+1\right)\prod _{i=1}^{n-1}\left(q^{2i}-1\right)}$	None	None
Exceptional Steinberg groups	2E6(q2)	${\displaystyle {\frac {q^{36)){(3,q+1)))\prod _{i\in \{2,5,6,8,9,12\))\left(q^{i}-(-1)^{i}\right)}$	None	None
	3D4(q3)	${\displaystyle q^{12}\left(q^{8}+q^{4}+1\right)\left(q^{6}-1\right)\left(q^{2}-1\right)}$	None	None
Suzuki groups	2B2(q) q = 22n+1 n ≥ 1	${\displaystyle q^{2}\left(q^{2}+1\right)\left(q-1\right)}$	None	None
Ree groups + Tits group	2F4(q) q = 22n+1 n ≥ 1	${\displaystyle q^{12}\left(q^{6}+1\right)\left(q^{4}-1\right)\left(q^{3}+1\right)\left(q-1\right)}$	None	None
	2F4(2)′	212(26 + 1)(24 − 1)(23 + 1)(2 − 1)/2 = 17971200
	2G2(q) q = 32n+1 n ≥ 1	${\displaystyle q^{3}\left(q^{3}+1\right)\left(q-1\right)}$	None	None
Mathieu groups	M11	7920
	M12	95040
	M22	443520
	M23	10200960
	M24	244823040
Janko groups	J1	175560
	J2	604800
	J3	50232960
	J4	86775571046077562880
Conway groups	Co3	495766656000
	Co2	42305421312000
	Co1	4157776806543360000
Fischer groups	Fi22	64561751654400
	Fi23	4089470473293004800
	Fi24′	1255205709190661721292800
Higman–Sims group	HS	44352000
McLaughlin group	McL	898128000
Held group	He	4030387200
Rudvalis group	Ru	145926144000
Suzuki sporadic group	Suz	448345497600
O'Nan group	O'N	460815505920
Harada–Norton group	HN	273030912000000
Lyons group	Ly	51765179004000000
Thompson group	Th	90745943887872000
Baby Monster group	B	4154781481226426191177580544000000
Monster group	M	808017424794512875886459904961710757005754368000000000

Cyclic groups, Z_p

Simplicity: Simple for p a prime number.

Order: p

Schur multiplier: Trivial.

Outer automorphism group: Cyclic of order p − 1.

Other names: Z/pZ, C_p

Remarks: These are the only simple groups that are not perfect.

Alternating groups, A_n, n > 4

Simplicity: Solvable for n < 5, otherwise simple.

Order: n!/2 when n > 1.

Schur multiplier: 2 for n = 5 or n > 7, 6 for n = 6 or 7; see Covering groups of the alternating and symmetric groups

Outer automorphism group: In general 2. Exceptions: for n = 1, n = 2, it is trivial, and for n = 6, it has order 4 (elementary abelian).

Other names: Alt_n.

Isomorphisms: A₁ and A₂ are trivial. A₃ is cyclic of order 3. A₄ is isomorphic to A₁(3) (solvable). A₅ is isomorphic to A₁(4) and to A₁(5). A₆ is isomorphic to A₁(9) and to the derived group B₂(2)′. A₈ is isomorphic to A₃(2).

Remarks: An index 2 subgroup of the symmetric group of permutations of n points when n > 1.

Groups of Lie type

Notation: n is a positive integer, q > 1 is a power of a prime number p, and is the order of some underlying finite field. The order of the outer automorphism group is written as d⋅f⋅g, where d is the order of the group of "diagonal automorphisms", f is the order of the (cyclic) group of "field automorphisms" (generated by a Frobenius automorphism), and g is the order of the group of "graph automorphisms" (coming from automorphisms of the Dynkin diagram). The outer automorphism group is often, but not always, isomorphic to the semidirect product ${\displaystyle D\rtimes (F\times G)}$ where all these groups ${\displaystyle D,F,G}$ are cyclic of the respective orders d, f, g, except for type ${\displaystyle D_{n}(q)}$, ${\displaystyle q}$ odd, where the group of order ${\displaystyle d=4}$ is ${\displaystyle C_{2}\times C_{2))$, and (only when ${\displaystyle n=4}$) ${\displaystyle G=S_{3))$, the symmetric group on three elements. The notation (a,b) represents the greatest common divisor of the integers a and b.

Chevalley groups, A_n(q), B_n(q) n > 1, C_n(q) n > 2, D_n(q) n > 3

	Chevalley groups, An(q) linear groups	Chevalley groups, Bn(q) n > 1 orthogonal groups	Chevalley groups, Cn(q) n > 2 symplectic groups	Chevalley groups, Dn(q) n > 3 orthogonal groups
Simplicity	A1(2) and A1(3) are solvable, the others are simple.	B2(2) is not simple but its derived group B2(2)′ is a simple subgroup of index 2; the others are simple.	All simple	All simple
Order	${\displaystyle {\frac {q^((\frac {1}{2))n(n+1))){(n+1,q-1)))\prod _{i=1}^{n}\left(q^{i+1}-1\right)}$	${\displaystyle {\frac {q^{n^{2))}{(2,q-1)))\prod _{i=1}^{n}\left(q^{2i}-1\right)}$	${\displaystyle {\frac {q^{n^{2))}{(2,q-1)))\prod _{i=1}^{n}\left(q^{2i}-1\right)}$	${\displaystyle {\frac {q^{n(n-1)}(q^{n}-1)}{(4,q^{n}-1)))\prod _{i=1}^{n-1}\left(q^{2i}-1\right)}$
Schur multiplier	For the simple groups it is cyclic of order (n+1,q−1) except for A1(4) (order 2), A1(9) (order 6), A2(2) (order 2), A2(4) (order 48, product of cyclic groups of orders 3, 4, 4), A3(2) (order 2).	(2,q−1) except for B2(2) = S6 (order 2 for B2(2), order 6 for B2(2)′) and B3(2) (order 2) and B3(3) (order 6).	(2,q−1) except for C3(2) (order 2).	The order is (4,qn−1) (cyclic for n odd, elementary abelian for n even) except for D4(2) (order 4, elementary abelian).
Outer automorphism group	(2,q−1)⋅f⋅1 for n = 1; (n+1,q−1)⋅f⋅2 for n > 1, where q = pf	(2,q−1)⋅f⋅1 for q odd or n > 2; (2,q−1)⋅f⋅2 for q even and n = 2, where q = pf	(2,q−1)⋅f⋅1, where q = pf	(2,q−1)2⋅f⋅S3 for n = 4, (2,q−1)2⋅f⋅2 for n > 4 even, (4,qn−1)⋅f⋅2 for n odd, where q = pf, and S3 is the symmetric group of order 3! on 3 points.
Other names	Projective special linear groups, PSLn+1(q), Ln+1(q), PSL(n + 1,q)	O2n+1(q), Ω2n+1(q) (for q odd).	Projective symplectic group, PSp2n(q), PSpn(q) (not recommended), S2n(q), Abelian group (archaic).	O2n+(q), PΩ2n+(q). "Hypoabelian group" is an archaic name for this group in characteristic 2.
Isomorphisms	A1(2) is isomorphic to the symmetric group on 3 points of order 6. A1(3) is isomorphic to the alternating group A4 (solvable). A1(4) and A1(5) are both isomorphic to the alternating group A5. A1(7) and A2(2) are isomorphic. A1(8) is isomorphic to the derived group 2G2(3)′. A1(9) is isomorphic to A6 and to the derived group B2(2)′. A3(2) is isomorphic to A8.	Bn(2m) is isomorphic to Cn(2m). B2(2) is isomorphic to the symmetric group on 6 points, and the derived group B2(2)′ is isomorphic to A1(9) and to A6. B2(3) is isomorphic to 2A3(22).	Cn(2m) is isomorphic to Bn(2m)
Remarks	These groups are obtained from the general linear groups GLn+1(q) by taking the elements of determinant 1 (giving the special linear groups SLn+1(q)) and then quotienting out by the center.	This is the group obtained from the orthogonal group in dimension 2n + 1 by taking the kernel of the determinant and spinor norm maps. B1(q) also exists, but is the same as A1(q). B2(q) has a non-trivial graph automorphism when q is a power of 2.	This group is obtained from the symplectic group in 2n dimensions by quotienting out the center. C1(q) also exists, but is the same as A1(q). C2(q) also exists, but is the same as B2(q).	This is the group obtained from the split orthogonal group in dimension 2n by taking the kernel of the determinant (or Dickson invariant in characteristic 2) and spinor norm maps and then killing the center. The groups of type D4 have an unusually large diagram automorphism group of order 6, containing the triality automorphism. D2(q) also exists, but is the same as A1(q)×A1(q). D3(q) also exists, but is the same as A3(q).

Chevalley groups, E₆(q), E₇(q), E₈(q), F₄(q), G₂(q)

Steinberg groups, ²A_n(q²) n > 1, ²D_n(q²) n > 3, ²E₆(q²), ³D₄(q³)

	Steinberg groups, 2An(q2) n > 1 unitary groups	Steinberg groups, 2Dn(q2) n > 3 orthogonal groups	Steinberg groups, 2E6(q2)	Steinberg groups, 3D4(q3)
Simplicity	2A2(22) is solvable, the others are simple.	All simple	All simple	All simple
Order	${\displaystyle {1 \over (n+1,q+1)}q^((\frac {1}{2))n(n+1)}\prod _{i=1}^{n}\left(q^{i+1}-(-1)^{i+1}\right)}$	${\displaystyle {1 \over (4,q^{n}+1)}q^{n(n-1)}(q^{n}+1)\prod _{i=1}^{n-1}\left(q^{2i}-1\right)}$	q36(q12−1)(q9+1)(q8−1)(q6−1)(q5+1)(q2−1)/(3,q+1)	q12(q8+q4+1)(q6−1)(q2−1)
Schur multiplier	Cyclic of order (n+1,q+1) for the simple groups, except for 2A3(22) (order 2), 2A3(32) (order 36, product of cyclic groups of orders 3,3,4), 2A5(22) (order 12, product of cyclic groups of orders 2,2,3)	Cyclic of order (4,qn+1)	(3,q+1) except for 2E6(22) (order 12, product of cyclic groups of orders 2,2,3).	Trivial
Outer automorphism group	(n+1,q+1)⋅f⋅1, where q2 = pf	(4,qn+1)⋅f⋅1, where q2 = pf	(3,q+1)⋅f⋅1, where q2 = pf	1⋅f⋅1, where q3 = pf
Other names	Twisted Chevalley group, projective special unitary group, PSUn+1(q), PSU(n + 1, q), Un+1(q), 2An(q), 2An(q, q2)	2Dn(q), O2n−(q), PΩ2n−(q), twisted Chevalley group. "Hypoabelian group" is an archaic name for this group in characteristic 2.	2E6(q), twisted Chevalley group	3D4(q), D42(q3), Twisted Chevalley groups
Isomorphisms	The solvable group 2A2(22) is isomorphic to an extension of the order 8 quaternion group by an elementary abelian group of order 9. 2A2(32) is isomorphic to the derived group G2(2)′. 2A3(22) is isomorphic to B2(3).
Remarks	This is obtained from the unitary group in n + 1 dimensions by taking the subgroup of elements of determinant 1 and then quotienting out by the center.	This is the group obtained from the non-split orthogonal group in dimension 2n by taking the kernel of the determinant (or Dickson invariant in characteristic 2) and spinor norm maps and then killing the center. 2D2(q2) also exists, but is the same as A1(q2). 2D3(q2) also exists, but is the same as 2A3(q2).	One of the exceptional double covers of 2E6(22) is a subgroup of the baby monster group, and the exceptional central extension by the elementary abelian group of order 4 is a subgroup of the monster group.	3D4(23) acts on the unique even 26-dimensional lattice of determinant 3 with no roots.

Suzuki groups, ²B₂(2²ⁿ⁺¹)

Simplicity: Simple for n ≥ 1. The group ²B₂(2) is solvable.

Order: q² (q² + 1) (q − 1), where q = 2²ⁿ⁺¹.

Schur multiplier: Trivial for n ≠ 1, elementary abelian of order 4 for ²B₂(8).

Outer automorphism group:

1⋅f⋅1,

where f = 2n + 1.

Other names: Suz(2²ⁿ⁺¹), Sz(2²ⁿ⁺¹).

Isomorphisms: ²B₂(2) is the Frobenius group of order 20.

Remarks: Suzuki group are Zassenhaus groups acting on sets of size (2²ⁿ⁺¹)² + 1, and have 4-dimensional representations over the field with 2²ⁿ⁺¹ elements. They are the only non-cyclic simple groups whose order is not divisible by 3. They are not related to the sporadic Suzuki group.

Ree groups and Tits group, ²F₄(2²ⁿ⁺¹)

Simplicity: Simple for n ≥ 1. The derived group ²F₄(2)′ is simple of index 2 in ²F₄(2), and is called the Tits group, named for the Belgian mathematician Jacques Tits.

Order: q¹² (q⁶ + 1) (q⁴ − 1) (q³ + 1) (q − 1), where q = 2²ⁿ⁺¹.

The Tits group has order 17971200 = 2¹¹ ⋅ 3³ ⋅ 5² ⋅ 13.

Schur multiplier: Trivial for n ≥ 1 and for the Tits group.

Outer automorphism group:

1⋅f⋅1,

where f = 2n + 1. Order 2 for the Tits group.

Remarks: Unlike the other simple groups of Lie type, the Tits group does not have a BN pair, though its automorphism group does so most authors count it as a sort of honorary group of Lie type.

Ree groups, ²G₂(3²ⁿ⁺¹)

Simplicity: Simple for n ≥ 1. The group ²G₂(3) is not simple, but its derived group ²G₂(3)′ is a simple subgroup of index 3.

Order: q³ (q³ + 1) (q − 1), where q = 3²ⁿ⁺¹

Schur multiplier: Trivial for n ≥ 1 and for ²G₂(3)′.

Outer automorphism group:

1⋅f⋅1,

where f = 2n + 1.

Other names: Ree(3²ⁿ⁺¹), R(3²ⁿ⁺¹), E₂^∗(3²ⁿ⁺¹) .

Isomorphisms: The derived group ²G₂(3)′ is isomorphic to A₁(8).

Remarks: ²G₂(3²ⁿ⁺¹) has a doubly transitive permutation representation on 3^3(2n+1) + 1 points and acts on a 7-dimensional vector space over the field with 3²ⁿ⁺¹ elements.

Sporadic groups

Mathieu groups, M₁₁, M₁₂, M₂₂, M₂₃, M₂₄

Janko groups, J₁, J₂, J₃, J₄

Conway groups, Co₁, Co₂, Co₃

Fischer groups, Fi₂₂, Fi₂₃, Fi₂₄′

Higman–Sims group, HS

Order: 2⁹ ⋅ 3² ⋅ 5³ ⋅ 7 ⋅ 11 = 44352000

Schur multiplier: Order 2.

Outer automorphism group: Order 2.

Remarks: It acts as a rank 3 permutation group on the Higman Sims graph with 100 points, and is contained in Co₂ and in Co₃.

McLaughlin group, McL

Order: 2⁷ ⋅ 3⁶ ⋅ 5³ ⋅ 7 ⋅ 11 = 898128000

Schur multiplier: Order 3.

Outer automorphism group: Order 2.

Remarks: Acts as a rank 3 permutation group on the McLaughlin graph with 275 points, and is contained in Co₂ and in Co₃.

Held group, He

Order: 2¹⁰ ⋅ 3³ ⋅ 5² ⋅ 7³ ⋅ 17 = 4030387200

Schur multiplier: Trivial.

Outer automorphism group: Order 2.

Other names: Held–Higman–McKay group, HHM, F₇, HTH

Remarks: Centralizes an element of order 7 in the monster group.

Rudvalis group, Ru

Order: 2¹⁴ ⋅ 3³ ⋅ 5³ ⋅ 7 ⋅ 13 ⋅ 29 = 145926144000

Schur multiplier: Order 2.

Outer automorphism group: Trivial.

Remarks: The double cover acts on a 28-dimensional lattice over the Gaussian integers.

Suzuki sporadic group, Suz

Order: 2¹³ ⋅ 3⁷ ⋅ 5² ⋅ 7 ⋅ 11 ⋅ 13 = 448345497600

Schur multiplier: Order 6.

Outer automorphism group: Order 2.

Other names: Sz

Remarks: The 6 fold cover acts on a 12-dimensional lattice over the Eisenstein integers. It is not related to the Suzuki groups of Lie type.

O'Nan group, O'N

Order: 2⁹ ⋅ 3⁴ ⋅ 5 ⋅ 7³ ⋅ 11 ⋅ 19 ⋅ 31 = 460815505920

Schur multiplier: Order 3.

Outer automorphism group: Order 2.

Other names: O'Nan–Sims group, O'NS, O–S

Remarks: The triple cover has two 45-dimensional representations over the field with 7 elements, exchanged by an outer automorphism.

Harada–Norton group, HN

Order: 2¹⁴ ⋅ 3⁶ ⋅ 5⁶ ⋅ 7 ⋅ 11 ⋅ 19 = 273030912000000

Schur multiplier: Trivial.

Outer automorphism group: Order 2.

Other names: F₅, D

Remarks: Centralizes an element of order 5 in the monster group.

Lyons group, Ly

Order: 2⁸ ⋅ 3⁷ ⋅ 5⁶ ⋅ 7 ⋅ 11 ⋅ 31 ⋅ 37 ⋅ 67 = 51765179004000000

Schur multiplier: Trivial.

Outer automorphism group: Trivial.

Other names: Lyons–Sims group, LyS

Remarks: Has a 111-dimensional representation over the field with 5 elements.

Thompson group, Th

Order: 2¹⁵ ⋅ 3¹⁰ ⋅ 5³ ⋅ 7² ⋅ 13 ⋅ 19 ⋅ 31 = 90745943887872000

Schur multiplier: Trivial.

Outer automorphism group: Trivial.

Other names: F₃, E

Remarks: Centralizes an element of order 3 in the monster, and is contained in E₈(3), so has a 248-dimensional representation over the field with 3 elements.

Baby Monster group, B

Order:

   2⁴¹ ⋅ 3¹³ ⋅ 5⁶ ⋅ 7² ⋅ 11 ⋅ 13 ⋅ 17 ⋅ 19 ⋅ 23 ⋅ 31 ⋅ 47

= 4154781481226426191177580544000000

Schur multiplier: Order 2.

Outer automorphism group: Trivial.

Other names: F₂

Remarks: The double cover is contained in the monster group. It has a representation of dimension 4371 over the complex numbers (with no nontrivial invariant product), and a representation of dimension 4370 over the field with 2 elements preserving a commutative but non-associative product.

Fischer–Griess Monster group, M

Order:

   2⁴⁶ ⋅ 3²⁰ ⋅ 5⁹ ⋅ 7⁶ ⋅ 11² ⋅ 13³ ⋅ 17 ⋅ 19 ⋅ 23 ⋅ 29 ⋅ 31 ⋅ 41 ⋅ 47 ⋅ 59 ⋅ 71

= 808017424794512875886459904961710757005754368000000000

Schur multiplier: Trivial.

Outer automorphism group: Trivial.

Other names: F₁, M₁, Monster group, Friendly giant, Fischer's monster.

Remarks: Contains all but 6 of the other sporadic groups as subquotients. Related to monstrous moonshine. The monster is the automorphism group of the 196,883-dimensional Griess algebra and the infinite-dimensional monster vertex operator algebra, and acts naturally on the monster Lie algebra.

Non-cyclic simple groups of small order

(Complete for orders less than 100,000)

Hall (1972) lists the 56 non-cyclic simple groups of order less than a million.