## Tax timeline
The **tax timeline** under Planning projects taxable income, federal brackets, and estimated taxes year by year through your planning horizon. It reflects detailed income lines, planned Roth conversions, withdrawals, and Required Minimum Distributions so you can spot high-tax years before they happen.
## Federal tax brackets in projections
Analyzer uses a **federal bracket catalog** by filing status and year to estimate ordinary income tax in projections. Bracket boundaries drive the Roth **bracket-filling** tools: they show headroom remaining in your current bracket before the next rate applies. State taxes vary and are simplified—treat results as educational estimates.
## What IRMAA is
**IRMAA** (Income-Related Monthly Adjustment Amount) is a surcharge added to Medicare Part B and Part D premiums when your **MAGI** exceeds tier thresholds. IRMAA uses a **two-year lookback**: your premiums at 65 depend on income reported at 63. Crossing a tier boundary by even one dollar triggers the full surcharge for that tier.
## How Analyzer models IRMAA
Analyzer's tax projection applies IRMAA tier tables to your projected MAGI with the two-year lookback, and can include the resulting Medicare premium surcharges in detailed expenses. Roth conversion tools flag years where a proposed conversion would push MAGI into a higher IRMAA tier.
## Roth conversions, IRMAA, and ACA subsidies
A Roth conversion raises MAGI in the conversion year, which can trigger IRMAA tiers (if you are near Medicare age) or reduce **ACA premium subsidies** (if you buy marketplace health insurance before 65). Analyzer's conversion tools surface these cliffs so you can size conversions below them.
Educational content only—not personalized investment, tax, or legal advice.