Ia

	Ia	Ib	II	III	IV	V
Early O	O3 If*
Mid O	O4 If+ O4 If+ O5 If+ O5 If+ O6 I(n)fp O6: f?pe	O6 Ib(n)(f)		O5 III(f) O5 III(f) O6 III(n)(f) O6.5 III(f)		O4 V((f)) O5 V((f)) O6 V((f)) O6.5 V((f))
Late O	O7 Ianfp O7.5 Iaf	O7 Ib(f) + O8-9 I O8 Ib(f) O9.5 Ib O9 Iab O9.5 Iab	O7 II(f)	O7 III((f)) O7.5 III(n)(f) O8 III((f)) O9 III		O7 V((f)) O8 V O9 V O9.5 Vep O9.5 Vn O9.5 V
Early B	B0 Ia B0 Ia B0.5 Ia BC0.7 Ia var B1 Ia B2 Ia B3 Ia	B1 Iab B1 Ib B1 Ib? B2 Ib	B1 III B2 III B3 III		B2 IV B3 IV	B0 V B0.5 V B1 V B1.5 V B2 V B2 V B3 V B3 V B3 V
Mid B		B5 Iab B5 Ib B6 Ib	B5 III		B5 IV	B5 V
Late B	B8 Ia B8 Ia	B8 Ib B9 Ib	B8 III B8.5 III B9.5 III-IV			B7 V B7 V B8 Vnn B8 V

Early A	A0 Ia A2 Ia A3 Ia	A0 Ib A3 I ab	A3 II	A0 III A1 III- A2 III	A0 IV A1 IVs A1 IV A1 IV A2 IV A3 IV	A0 Va A0 Va A1 Va A1mA2 Va A2 Va A3 Va A3 Va
Mid A			A5 II	A4 III A5 III	A4 IV A5 IV A5 IV A6 IV	A4 V A5 Vn A6 V
Late A	A9 Ia	A7 Ib	A7 II-	A7 III A8 III A9 IIIb	A7 IV	A7 V A8 Vn A9 V
Early F	F0 Ia	F0 Ib F2 Ibp F2 Ib	F0 II	F0 IIIa F2 III F3 III	F2 IV -V	F1 V F1 V+ F2 V F2 V
Mid F	F5 Ia	F5 Ib	F5 II-III		F5 IV - V	F6 V
Late F		F8 Ib		F8 III		F9 V F9.5 V

Early G		G0 Ib G0 Ib G1 Ib G2 Ib-IIa G2 Ib	G1 II	G0 IIIp G2 IIIb	G0 IV G0 IV G2 IV	G0 V G0 V G1 Va G1.5 Vb G2 V G3 V
Mid G	G4 Ia	G5 Ib G5 Ib-IIa	G5 II	G5 III-IV G5 IIIa	G5 IV	G4 V G5 V G6.5 V
Late G		G8 Ib		G7 IIIa G8- IIIab G8 III G8 III Fe-1 G8+ III G9 III G9 III G9 III G9.5 III CN0.5		G8 V G8 V
Early K		K0- Ib K0 Ib K1.5 Ib K2 Ib K3 Ib	K0+ II K2 II K3- II b K3 II K3 II K3 II ab	K0 IIIB K0- III K1.5 III Fe-0.5 K1 III K2 III K2 III K2 III K2.5 III K3 III	K0+ IV K1 IVa	K0 V K2 V K2 V K3- V
Mid K		K4 Ib K5 Ib	K5+ II	K4 III K4 III K4.5 III K5- III K5 III K5 III K5.5 III		K4 V K5 V K6e V Fe-1
Late K				K7 III		K7 V
Early M	M1-M2 Ia-Iab M2- Ia M3 Iae	M0.5 Ib M2- Ib M2 Iab-Ib M3 Iab M3+ Iab var?	M0 II M2+ IIab M3 II	M0- III M0 III M0+ IIIa M0- IIIb M1 III M1 III M2 III M3 III M3 III M3 III M3 IIIab		M0 V M1- V dM1.5 M3 V
Mid M			M4 II M4 II	M4 III M4 IIIa M5- III M6- III		M6 de
Late M