Income tax deductions 2026 — what can you still deduct in box 1?
Mortgage interest (phasing down), donations (≥1% aggregate income), medical (≥total threshold), study costs (abolished 2022), partner alimony. Thresholds explained.
Main box 1 deductions 2026: (1) MORTGAGE INTEREST — eigenwoningforfait + interest deduction; interest phased down since 2014 (max deductible at 36.93% vs top bracket 49.5%); (2) DONATIONS — periodic (annual fixed to ANBI/association) fully deductible; one-off: 1% threshold of aggregate income, max 10%; (3) MEDICAL — specific care costs above income threshold; (4) PARTNER ALIMONY — monthly to ex-partner fully deductible; (5) DISABILITY BENEFIT — partner-related; (6) HEALTH INSURANCE self-employed — limited; (7) STUDY COSTS — for those over 30 ABOLISHED 1 Jan 2022; replaced by STAP budget (€1,000 max); (8) PRIVATE CAR FOR BUSINESS — addition rules. Threshold rules: many deductions only allowed above threshold (% of aggregate income). For IB objection on missed deduction: ALWAYS attach evidence (invoices, statements, ANBI declaration). For what fits your situation: free tax tools (Tax Office, Konsult, GreenJinn) or paid advisor €120-€200.