How bol charges commission
For every item sold bol charges a percentage of the selling price including VAT, plus a fixed fee. The percentage depends on the category; the fixed fee on the type of item and the price band. bol's own example: €206.50 × 12.4% + €0.95 = €26.55.
The calculator also shows what is left of your price after VAT and commission. Your purchase, shipping and packaging still come out of that. Work those out in the floor price calculator.
Choosing the category
The list shows the range from bol's commission table, not an exact rate: within a category it differs per product group. The rate for your item is in your seller account under Items. The full table is on commission per category.
Watch the price bands
Because the fixed fee differs per price band, a slightly more expensive item can earn you less. When a price sits close to a boundary, work out both prices with the rate from your account.