Renting: the rents over the period, minus the income-tax credit (15% of rent, up to €900 in 2026 and €1,000 after). Buying: deposit, transfer tax and deed, payments, IMI, maintenance and building fees, minus what you recover on sale after the debt and the agent's fee.

The two numbers that change the answer most are appreciation and how long you stay. Be conservative on the first: last year's +16.5% (INE, Q2 2026) is not a forecast.