A jacket that fits is mostly a matter of five numbers. Take them once, write them down, and you can order leather with confidence anywhere.
What you need
A soft tape measure and a well-fitting shirt. Measure over the shirt, not over a heavy jumper, and stand naturally — pulling your shoulders back will give you a chest measurement you cannot actually wear.
The five measurements
1. Chest
Run the tape around the fullest part of your chest, under the arms and across the shoulder blades. Keep it level and snug without compressing. Breathe normally and take the reading on the exhale.
This is the measurement most size charts lead with.
2. Shoulder
Measure across the back, from the outer edge of one shoulder to the other — the point where the flat top of your shoulder turns down into your arm.
This is the most important number in the list, because it is the one alteration cannot fix. If the shoulder is wrong, the jacket is wrong.
3. Sleeve
From the shoulder point, down the outside of a slightly bent arm, to the wrist bone. Bending the arm matters: a sleeve measured straight will be too short in use.
A leather sleeve should end at the wrist bone, showing about a centimetre of shirt cuff.
4. Jacket length
From the base of the collar seam at the back of the neck, straight down to where you want the jacket to finish. For a biker or café racer, that is usually at or just below the belt line. For a blazer or a longer jacket, it is at the hip.
5. Waist
Around the natural waist — the narrowest point, usually just above the navel. This matters most for belted bikers and tailored leather blazers, where the jacket is shaped rather than straight.
Reading a size chart
Size charts come in two forms, and mixing them up is the usual cause of an ordering mistake:
- Body measurements describe the person the size is cut for.
- Garment measurements describe the finished jacket, laid flat, and already include the ease built into the cut.
A jacket cut for a 100 cm chest will typically have a garment chest of 106–112 cm, depending on whether it is a slim café racer or a relaxed bomber. If a chart does not say which it is quoting, ask before ordering.
Between sizes
Start with the shoulder. If one size matches your shoulder measurement and the other does not, take the one that does and accept slightly more or less room elsewhere.
Where the shoulder fits in both, the deciding factor is what you will wear underneath. A jacket you will wear over shirts can go with the smaller size; one you will wear over a lambswool crew needs the larger.
What a good fit feels like
Put the jacket on, close it fully, and run through four checks:
- A flat hand should slide between the closed jacket and your chest.
- Raising your arms forward should not lift the whole jacket off your hips.
- The collar should sit flat against the back of your neck, not stand away from it.
- The sleeve head — the seam where sleeve meets body — should not have diagonal pull lines running into the chest.
What height and weight cannot tell you
Two people at the same height and weight can differ by 10 cm in the shoulder. Any tool that promises a size from height and weight alone is guessing, and it is guessing in the measurement that cannot be altered. Use those tools as a starting suggestion, never as a substitute for a tape measure.
