Calculadora Roth IRA vs Conta Tributável
Compare o crescimento de longo prazo em conta com benefício fiscal versus corretora tributada.
Conceitos-chave
Roth account
Contributions are after-tax; qualified growth and withdrawals are tax-free in many jurisdictions (IRA rules vary).
Taxable brokerage
Investing account where dividends and realized capital gains can be taxed annually or at sale.
O que esta ferramenta faz
Tax location can matter as much as return
Two investors earning the same market return can finish with very different spendable wealth if one compounds inside a Roth-style wrapper and the other pays tax on gains. This calculator makes that gap visible.
How to use this tool
Set contribution, return, horizon, and tax rates. We apply contribution tax so both accounts are funded from comparable after-tax cash, then estimate a terminal capital-gains haircut on the taxable account.
Formulas used
Monthly growth: balance = balance × (1 + r/12) + contribution Taxable after-tax ≈ balance − (balance − basis) × capital gains rate
Roth contributions and growth are treated as tax-free at withdrawal for this educational model. Taxable account basis grows with after-tax contributions; unrealized gains are taxed at the capital gains rate at the end.
Worked example
Invest the after-tax equivalent of $500/month for 30 years at 8%. With a 24% contribution tax rate and 15% capital gains tax, the Roth balance often pulls ahead of the taxable account's after-tax value — especially when compounding runs for decades.
Decision checklist
0/5 marcados
Marque os itens conforme valida sua decisão.
Common mistakes
- Comparing pre-tax contributions without equalizing take-home cash.
- Ignoring contribution limits and income phaseouts.
- Assuming capital gains tax applies to the entire taxable balance including basis.
Methodology on this page
Simplified educational model. It does not simulate annual dividend drag, wash sales, state taxes, early withdrawal penalties, or changing tax law.
Read the full FinTools4U methodology →Perguntas frequentes
Is this only for U.S. Roth IRAs?
The math is generic for after-tax tax-free wrappers vs taxable accounts. Labels say Roth because search demand is high; local product names differ.
Do you model dividend taxes each year?
Not in this version. The taxable path applies an end-of-horizon gains estimate, which can understate drag for high-dividend portfolios.
What if my tax rate changes?
Adjust the sliders. Higher future ordinary rates usually increase the relative value of Roth-style accounts.
Are contribution limits enforced?
No. Enter contributions you believe you can legally make.
Sources & further reading
- IRS — Roth IRAs — Official U.S. Roth IRA overview (rules differ elsewhere).