The numbers below each size are the actual garment measurements in inches.
Upper School Boys Blazer Size Guide
| Boys Blazer | Size 12 | Size 14 | Size 16 | Size 18 |
| A. Length | 25 1/8 | 26 1/4 | 27 3/8 | 28 3/8 |
| B. Chest- Around | 35 1/2 | 37 | 38 1/2 | 40 |
| C. Shoulders | 15 | 15 1/2 | 16 | 16 1/2 |
| D. Sleeve Length - Top of Sleeve | 20 1/2 | 22 | 23 1/2 | 24 3/4 |
Upper School Boys/Mens Blazer Size Guide
| Mens Blazer | Size 36 R | Size 36 S | Size 36 L | Size 38 R | Size 38 S | Size 38 L | Size 40 R | Size 40 L | Size 42 R | Size 42 L | Size 44 R | Size 44 L | Size 46 R |
| A. Length - Center of Back | 30 | 28 1/2 | 31 1/2 | 30 1/4 | 28 3/4 | 31 3/4 | 30 1/2 | 32 | 30 3/4 | 32 1/4 | 31 | 32 1/2 | 31 1/4 |
| B. Chest - Around | 41 1/3 | 41 1/3 | 41 1/3 | 43 1/3 | 43 1/3 | 43 1/3 | 45 1/4 | 45 1/4 | 47 1/4 | 47 1/4 | 49 1/4 | 49 1/4 | 51 1/4 |
| C. Shoulders | 18 1/8 | 18 1/8 | 18 1/8 | 18 5/8 | 18 5/8 | 18 5/8 | 19 1/8 | 19 1/8 | 19 5/8 | 19 5/8 | 20 1/8 | 20 1/8 | 20 5/8 |
| D. Sleeve Length - Top of Sleeve | 24 3/4 | 24 3/4 | 26 1/4 | 25 | 24 3/8 | 26 1/2 | 25 1/4 | 26 | 25 1/2 | 27 | 25 3/4 | 27 1/8 | 26 |
A = Length – Center of Back
*The garment chest measurment should be larger than the body chest measurement to comfortably accommodate the oxford shirt and any other layer worn underneath the blazer.
B = Around Chest (all the way around)
C = Across Shoulders
D = Sleeve Length – Top of Sleeve
*The garment sleeve length should allow the shirt cuff to be visible beyond the blazer cuff (about half an inch).