By Meraj Uddin Provat · Last reviewed May 23, 2026 · Editorial Standards
Roth or Traditional is one of the most argued questions in retirement saving, and most of the argument is noise. Strip it down and it rests on a single comparison: your tax rate now versus your tax rate when you withdraw. This calculator makes that comparison concrete with your numbers.
Roth vs Traditional Calculator
Same money in, compared after tax at retirement. The answer hinges on one thing: your tax rate now vs later. Updates as you type.
Roth
Traditional
A simplified, illustrative model: equal annual contributions grow at a constant return. Roth is taxed at today’s rate before investing and withdrawn tax-free; Traditional grows pre-tax and is taxed at the retirement rate on withdrawal. Real outcomes involve brackets, RMDs, employer matches, contribution limits and changing law. Not tax or financial advice — consult a professional.
How to use this calculator
Enter your annual contribution, years until retirement, expected return, and two tax rates: your marginal rate now and your expected rate in retirement. The result is the after-tax value of each account, side by side, and which wins for your assumptions.
The one rule
- Traditional — contribute pre-tax, money grows untaxed, you pay tax on withdrawals. Best when your retirement tax rate is lower than today's (the common case for high earners who'll spend less in retirement).
- Roth — contribute after-tax, growth and withdrawals are tax-free. Best when your retirement tax rate is higher than today's (common for younger or lower-bracket savers who expect to earn more later).
If the two rates are equal, the after-tax results are nearly identical — that's not a bug, it's the underlying math. Everything else is a tiebreaker.
Why people get this wrong
The instinct is "tax-free sounds better, pick Roth." But Traditional's upfront deduction is real money you can also invest. The honest comparison is after-tax dollars in retirement for the same effort — which is exactly what this calculator does: it taxes the Roth contribution today before investing it, and taxes the Traditional balance at withdrawal. Judged that way, the winner is decided almost entirely by which tax rate is higher.
The tiebreakers (when rates are close)
When the core math is close to a wash, these tilt it:
- Roth has no required minimum distributions (RMDs) — more control in retirement and better for estate planning.
- Roth hedges future tax-rate risk — if you believe rates rise, paying tax now locks it in.
- Traditional lowers taxable income now — useful if the deduction keeps you under an income threshold (subsidies, phase-outs).
- Tax diversification — having both gives you withdrawal flexibility to manage your bracket in retirement.
- Employer match is always Traditional (pre-tax), regardless of which you choose for your own contributions.
A practical default
Many savers can't predict their retirement rate precisely. Two reasonable rules of thumb: choose Roth when you're early-career or in a low bracket (rates likely to rise for you), and Traditional when you're a high earner now (you'll likely draw down at a lower effective rate). When genuinely unsure, splitting contributions builds tax diversification and hedges the guess.
Frequently asked questions
Is Roth or Traditional better? Whichever faces the lower tax rate at the relevant time. Lower rate in retirement than now favors Traditional; higher rate later favors Roth. Equal rates are roughly a wash.
Why are the results identical when tax rates are the same? Because of the math: taxing money before investing or after growing produces the same result at one constant rate. The difference only appears when the two rates differ.
Does the employer match go into Roth? No. Employer matching contributions are always pre-tax (Traditional-style), even if your own contributions are Roth. They're taxed at withdrawal.
What about required minimum distributions? Traditional accounts generally require minimum distributions starting at a set age; Roth IRAs don't for the original owner. That flexibility is a real Roth advantage when the core math is close.
Should I split between both? Often a sound choice when you can't confidently predict your future rate. It diversifies tax exposure and gives you withdrawal flexibility to manage your bracket later.
Methodology
Equal annual contributions grow at a constant return for the chosen number of years (future value of an annuity). Traditional grows on the full pre-tax contribution and is taxed at the retirement rate at withdrawal. Roth taxes the contribution at today's rate before investing, then grows and withdraws tax-free. The after-tax ending values are compared. This is a simplified model: real outcomes involve tax brackets, RMDs, contribution limits, employer matches, and future law changes. Not tax or financial advice — consult a qualified professional.
Written by the CalcCottage team. We show the real number, not the marketing number.