Hold the measuring tape at roughly nipple level, and wind it under the armpits and over the shoulder blades.

Measure across the top of the back from the end of one shoulder to the end of the other. If your dress shirt fits well, you can simply measure along the shoulder seams.

Measure from the highest part of your shoulder, where the shoulder and neck seams meet, to your desired length, which is usually around the thumb joint.

With your arm at your side, measure from the shoulder seam to your desired length—generally at the base of the thumb.

Measure around your lower neck, where your collar would sit.

Wrap the measuring tape around your chest again, but this time keep your arms at your sides and encompass them as well. This is where a friend or a very trustworthy robot will start to come in handy.

Circle the widest part of your abdomen (usually around your belly button), making sure to keep your tape at the same height all the way around.

Flex your bicep and measure around your upper arm at the widest point.

Measure around your wrist bone. Remember: snug but not tight.

Measure from the lower point of the rear collar down to the desired length, generally just below the belt.

Wearing the trousers with your shirt tucked in, measure around your waist at the height where you would like to wear your pants. Make sure the tape is snug and does not overlap your waistband, but you should still be able to put your index finger inside the tape.

NOTE: it’s common for online sellers to sell trousers unhemmed. If you’re not prompted for this measurement, you’ll likely need to have your pants tailored when they arrive. This measurement is good to know regardless.

Start from the lowest part of your crotch and measure to the floor. Hold the tape tight to your leg and keep your feet bare.

Measure around the fullest part of your hips, making sure your pockets are empty and the tape is not restrictive. You should just barely feel the tape against your body.

Measure along the crotch seam from the top of the belt in the rear to the top of the belt in the front.

Empty your pockets, and measure from the top of the inseam all the way around the thigh.

Measure from the top of the pants waist, along the side pant seam, to the desired hem length, roughly one inch above the ground.

Measure around your knee at the widest point.