This happens because interest accrues on the outstanding balance for a longer period when tenure is extended. Two otherwise identical loans — same principal, same interest rate — but with one running 15 years and the other 25 years, can differ dramatically in total interest paid, even though the monthly EMI on the longer loan feels more manageable.
That said, a longer tenure isn't automatically the wrong choice. If a lower EMI genuinely makes the difference between comfortably managing your monthly budget versus being stretched thin, that flexibility has real value — financial stress has its own costs, and an unaffordable EMI you struggle to pay every month isn't necessarily the more 'optimal' choice just because it saves interest on paper.
A common middle-ground approach: take the longer tenure for lower mandatory monthly commitment and flexibility, but make voluntary prepayments whenever you have surplus cash, which effectively shortens the loan and cuts interest, while still giving you the lower-EMI safety net in months when cash is tighter.