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| ST | Mv Range | ST | Mv Range |
| Hot O | <-6.0 | B6 | [-0.6; -0.25[ |
| O3 | [-6.0; -5.9[ | B7 | [-0.25; 0.025[ |
| O4 | [-5.9; -5.7[ | B8 | [0.025; 0.285[ |
| O5 | [-5.7; -5.5[ | B9 | [0.285; 0.43] |
| O6 | [-5.5; -5.2[ | A0 | ]0.43; 1.0[ |
| O7 | [-5.2; -4.9[ | A1 | [1.0; 1.3[ |
| O8 | [-4.9; -4.5[ | A2 | [1.3; 1.5[ |
| O9 | [-4.5; -4.2[ | A3-A4 | [1.5; 1.95[ |
| B0 | [-4.2; -3.25[ | A5-A6 | [1.95; 2.2[ |
| B1 | [-3.25; -2.55[ | A7 | [2.2; 2.4[ |
| B2 | [-2.55; -1.8[ | A8-A9 | [2.4; 2.55[ |
| B3 | [-1.8; -1.4[ | F0-F1 | [2.55; 3.6[ |
| B4 | [-1.4; -0.95[ | cool F |  3.6
|
| B5 | [-0.95; -0.6[ |
1 The classification is based on ranges in absolute V magnitude per spectral sub-type, following the calibration of Lang (1992) and Wisniewski & Bjorkman (2006, and references therein) for main-sequence stars.
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