Short answer: Fixed = same rate for 1-5 years, payment certainty. Floating = moves with market, more flexible.
A fixed rate stays the same for a set period (1-5 years). Your payments do not change. A floating rate moves with the market. It can go up or down. Fixed gives certainty. Floating gives flexibility. Most people fix part and float part to get both benefits.
Fixed Rate: 6.5% for 2 years
Floating Rate: 7.2% (current)
Loan Amount: $500,000
Fixed Payment: $3,160/month
Floating Payment: $3,382/month (if rates rise)
Split Option: 70% fixed, 30% floating