Standard vs Itemized Deduction Calculator

How it is calculated

You type your own standard deduction amount, which depends on your filing status and tax year, together with each itemized category. The tool then caps the state and local taxes (SALT) line by the US rule for the tax year you pick: $40,000 for 2025, 1% more each year through 2029 ($40,400 for 2026, $41,624 for 2029), and $10,000 from 2030. If you enter a modified AGI above $500,000 ($505,000 in 2026, also rising 1% a year), the cap shrinks by 30% of the excess but never below $10,000; married filing separately halves every one of these figures. Then it adds the categories: itemized = mortgage + min(SALT, cap) + charity + medical + other. Empty category fields count as 0, and an empty AGI means you are below the threshold. The better choice is max(standard, itemized), and the gap is |itemized − standard|. Medical costs are added exactly as entered, so type only the deductible part. The result is a deduction, not a tax saving; the tax effect depends on your bracket.

Common mistakes

• Expecting the tool to know your standard deduction. You must enter the amount for your filing status and year yourself; leaving it empty gives no result.
• Leaving the AGI blank when your modified AGI is above $500,000 (or $250,000 filing separately). The higher cap then counts in full and the itemized total comes out too high.
• Picking the wrong tax year. From 2030 the cap is back to $10,000, and 2024 or earlier returns used $10,000 too, which this tool does not cover.
• Entering total medical expenses. The tool adds the figure as typed and applies no income threshold.
• Reading the "better by" figure as money back. It is extra deduction; the tax saved is that amount times your marginal rate.