Polish banks and bookmakers explain margins on loans and bets

Bank margin is the fixed percentage profit that a bank adds to a variable reference rate such as WIBOR when calculating mortgage interest. It is paid in every monthly instalment and directly determines the total cost of a home loan. The level of the margin depends on the borrower’s risk profile, loan‑to‑value ratio, creditworthiness and any cross‑selling of additional products. Borrowers can lower the margin by meeting promotional conditions or refinancing with another bank.

Bookmaker margin, also called the overround, is the hidden commission that betting operators embed in odds to guarantee a profit regardless of the event outcome. The sum of the implied probabilities of all possible results exceeds 100 %; the excess percentage is the margin. A higher margin results in lower odds for the player and reduces long‑term profitability. The margin can be calculated by adding the reciprocals of the offered odds and multiplying by 100. Tools that remove the margin reveal the fair odds and help bettors identify value bets.