Where is the room intended to be?
A boxy jumper can be broad through the body with a relatively short hem. A long, loosely draping design distributes its volume differently. Compare the jumper with its intended shape rather than with a fitted top. If you want a closer outline, another cut may make more sense than choosing several sizes smaller.
Look at the neckline. Does it remain in a position you find comfortable as you move? A roomy body may be intentional while a neckline that constantly slides backwards becomes distracting. Arrange the jumper normally once, then notice whether you repeatedly need to pull it forwards.
Check hands and sleeves during use
Let your arms hang, then reach for an object. Long sleeves may be part of the design but should still allow the activities you plan. If you intend to turn them back, check that the fold stays and feels comfortable at the wrist. Sleeves pushed up briefly for a photograph are not yet a tested solution.
Put the intended jacket over the jumper. Extra knitwear around the upper arm also needs space inside the jacket. Bunched material beneath a close sleeve can feel uncomfortable even when the jumper fits well by itself. Decide whether you intend to wear it mainly without that jacket or need a different combination.
Compare two sizes with the same bottom
Try both sizes with the same trousers or skirt. Notice hem length, neckline position and the fabric that gathers when you sit. The smaller version is not automatically the better fit because it shows less volume. The larger one is not automatically the intended relaxed version either.
Choose the jumper whose roominess you deliberately enjoy and whose position works during ordinary movement. If both sizes cause problems in different places, look for another cut. A relaxed shape that suits you does not require continual explanation or correction through pulling it into position.
