Shirt Size & Fit Planner

First, the calculator converts all inputs to one unit system (inches or cm). It estimates collar size from your neck circumference with a small wearing-ease allowance, then compares your measured sleeve length to your arm reference (shoulder-to-wrist/center-back-to-wrist) to determine whether sleeves are likely short, standard, or long. Finally, it uses your height plus your selected body-length preference (Short/Regular/Long) to flag whether a standard hem is likely to be too high/low for tuck-in wear.

Different brands vary in collar spread, cuff style, and how much “real” wearing ease they build in, so the size match is an estimate—not a guarantee. Sleeve length can also change based on how you measure (arm relaxed vs. slightly bent) and where the tape starts/ends at the wrist. For the body length suggestion, tuck-in expectations matter: some people want more coverage than “average” and will prefer Long even when Regular might work.

If your sleeve delta (difference from the reference) is close to the tolerance, the tool returns the nearest sleeve/size option and marks it as “alteration likely.” If you enter measurements that don’t pass basic plausibility checks (e.g., non-positive values, sleeve length unrealistically close to the reference minus allowance), you’ll get an input alert instead of a misleading recommendation. For unusual proportions, the calculator can still guide you, but you should treat the result as higher risk and consider checking the return/exchange policy.

Use consistent units: if you switch to cm, enter all length fields in cm. Measure with the shirt-off body method you’ll use in real life—especially sleeve length—so the comparison to your shoulder-to-wrist (or center-back-to-wrist) reference stays accurate. This planner focuses on collar, sleeve length, and body length; it does not model chest/waist fit, shoulder width, or fabric stretch, so you may still need a size adjustment based on those factors.