How do I choose between variable and fixed interest rates on a Swedish mortgage?

Variable rate ("rörlig ränta") follows the market and is historically cheaper over time, but your costs fluctuate. Fixed rate ("bunden ränta") provides security and predictability for 1-10 years. Many split their loan: part variable to benefit from lower average rates and part fixed for security. You can split into multiple parts with different fixed terms ("räntebindningstid") (e.g., 50% variable, 25% fixed 2 years, 25% fixed 5 years). If you want to pay off a fixed loan early, there may be interest rate differential compensation ("ränteskillnadsersättning") calculated on the difference between your rate and current rates.