How much can I rely on the numbers in the size chart when choosing washed clothes?

To give the numbers first, it is 1–3cm. Garments that have undergone washing, such as Washed Loose Fit Sweatpants, can have size deviations of this amount, and because this stems from the process, it is not considered grounds for a refund or exchange^[1]. Since the unit in the size chart is also cm^[2], you can understand that there is this range of variation between the values written in the chart and the garment you actually receive.

Washing is a process in which finished garments are treated with water, chemicals, and heat. In this process, the degree to which the fabric shrinks or stretches varies slightly from garment to garment, so even if they are cut to the same size, final measurements generally do not come out to one exact, identical value. LOW CLASSIC also clearly states the standard that such handling precautions noted on the product page are not regarded as defects^[3].

Therefore, when choosing, rather than treating the numbers in the chart like precise decimals, it is safer to leave plenty of room for your desired fit. Care after receiving the item follows the same principle — generally, for washed cotton products, shrinkage increases with hot water washing and machine drying, so washing in cold water and avoiding heat drying will make it relatively easy to maintain the dimensions you initially received.

hmmm, this single line is close to a signal that weighing two sizes over a 1cm difference in total length does not work well when it comes to washed clothes.