How do I calculate the Modelo 210 for mixed use?

For mixed use — partly rented, partly owner-occupied — two separate calculations and two separate declarations are generally required. Example: EU/EEA resident, sole owner, cadastral value €200,000, imputation rate 1.1%, 90 days rented (rental receipts €9,000, expenses €3,500), 275 days self-use. Rental portion: net rental income = €9,000 – €3,500 = €5,500. Tax = €5,500 × 19% = €1,045. Filing deadline for tax year 2025: 1–20 January 2026. From tax year 2026 (Orden HAC/623/2026): 1–20 April of the following year (for grouped annual returns; a transitional rule applies for separate returns in 2026). Self-use portion: imputed income = €200,000 × 1.1% × 275/365 = €1,657.53. Tax = €1,657.53 × 19% = €314.93. Deadline for tax year 2025: 1 January to 31 December 2026. From tax year 2026: 1 April to 31 December of the following year. Total tax: €1,045 + €314.93 = €1,359.93. With two co-owners, the number of declarations generally doubles to four. The most common error: filing only one declaration.