Understand how taxes affect every financial decision you make.
Tax planning isn't just about April 15th. Every investment, withdrawal, and conversion decision has a tax consequence — and the difference between a tax-aware strategy and a tax-blind one compounds dramatically over decades. These tools help you see the full picture before you act.
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Roth Conversion Calculator
Model the tax impact of converting traditional IRA or 401(k) balances to Roth. See how conversion amounts interact with your tax bracket, Medicare IRMAA surcharges, and future RMD obligations.
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Frequently Asked Questions
What's the difference between my marginal and effective tax rate?
Your marginal rate is the rate applied to the last dollar of taxable income — the rate of your highest bracket. Your effective rate is your total tax bill divided by your total taxable income, reflecting the average rate across all income tiers. Because the U.S. has a progressive system, lower slices of income are taxed at lower rates. A single filer with $100,000 of taxable income in 2025 has a 22% marginal rate but an effective rate closer to 14–15%. The marginal rate is what matters for decisions at the edge — like whether a pre-tax 401(k) contribution saves you 22 cents or 32 cents per dollar. The effective rate describes your overall tax burden.
Should I take the standard deduction or itemize?
Take whichever is larger. For 2025, the standard deduction is $15,000 for single filers and $30,000 for married filing jointly. Itemizing makes sense only if your deductible expenses exceed that threshold. Common itemizable deductions include mortgage interest (on up to $750,000 of acquisition debt), state and local taxes (SALT, capped at $10,000), and charitable contributions. Since the Tax Cuts and Jobs Act nearly doubled the standard deduction in 2018, roughly 90% of filers now take the standard deduction. If you're close to the threshold, "bunching" deductions — concentrating two years of charitable giving into one year — can help you itemize in alternate years.
How are long-term capital gains taxed differently from ordinary income?
Long-term capital gains — profits on assets held more than one year — are taxed at preferential rates: 0%, 15%, or 20%, depending on your taxable income. Short-term gains on assets held a year or less are taxed as ordinary income at your marginal rate, which can be as high as 37%. For most middle-income investors, the long-term rate is 15%. High earners may also owe the 3.8% Net Investment Income Tax on top of the 20% rate. The practical implication is significant: a $50,000 gain on a stock held 13 months versus 11 months can mean the difference between paying $7,500 and $16,000 in federal tax for a typical filer.
What is the AMT and who does it affect in 2025?
The Alternative Minimum Tax is a parallel tax calculation designed to ensure high earners pay at least a minimum level of tax regardless of deductions. It applies a flat 26–28% rate to a broader income base that disallows certain deductions allowed under regular tax rules. You owe the AMT only if your AMT liability exceeds your regular tax liability — you pay whichever is higher. Since the TCJA significantly raised AMT exemptions, it now primarily affects people with income above $200,000, large incentive stock option exercises, or substantial "preference items." The 2025 AMT exemption is $88,100 for single filers and $137,000 for married filing jointly, phasing out above $626,350 and $1,252,700 respectively.
When does a Roth conversion make the most sense from a pure tax standpoint?
The ideal time to convert is when your current-year taxable income is abnormally low relative to what you expect in future years. This creates an arbitrage: pay tax today at a lower rate than you'd pay on the same dollars later when RMDs inflate your income. Tactically, convert up to the top of your current bracket without spilling into the next. Key scenarios: the gap between retiring and starting Social Security, a year with large business losses, or early retirement years before RMDs begin. You should also model whether the conversion amount might trigger Medicare IRMAA surcharges two years later, which can add effective marginal rates of 8–14% on top of your bracket.
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