Usage patterns
〈物〉に利子がつくinterest accrues on something (e.g. a deposit)
This account earns 0.1% interest per year.
利子を払うto pay interest
I pay interest on my loan every month.
利子を得るto earn/receive interest
You can earn interest with a fixed deposit.
利子が高い/低いthe interest is high/low
That bank's interest is higher than others.