system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does buying a house "build equity"?
gpt
Lets say a house is worth 250K. You borrow 230K and put down a 20K deposit. You now have 20K equity in the house. It's the value of your holding minus your debt. As you pay down the mortgage, your equity percentage rises until eventually you own the house. If the prices have remained stable or risen, you've also gained a paper profit that you can realize when you sell.       
The process of paying off the mortgage is what builds the equity.