Roth vs Traditional Calculator – Tax Now vs Later Comparison

Why $10,000 Pre-Tax Today Becomes $76,122 In 30 Years But After-Tax Difference Is $2,814?

You have $10,000 pre-tax dollars available to invest. Current tax rate 22% marginal, retirement tax rate 22% expected, return 7% per year for 30 years. Traditional IRA 401k invests full $10,000 pre-tax, grows tax-deferred $10,000×(1.07)^30=$76,122 future before tax, after-tax at withdrawal 22% retirement = $76,122×(1-22%)=$59,375 after-tax future. Roth IRA pays tax now 22% $2,200, invests after-tax $7,800, grows tax-free $7,800×(1.07)^30=$59,375 after-tax future same as Traditional when rates equal. Breakeven is current rate = retirement rate after-tax equal.

If retirement rate higher 28% vs current 22%, Traditional after-tax $76,122×(1-28%)=$54,808 Roth still $59,375 Roth wins by $4,567. If retirement rate lower 12% vs current 22%, Traditional after-tax $76,122×(1-12%)=$66,987 Roth $59,375 Traditional wins by $7,612. Traditional saves tax now $10,000×22%=$2,200 savings now, Roth pays $2,200 now for tax-free later. RMDs force Traditional withdrawals starting age 73 pushing taxable income higher, Roth IRA no RMDs during owner lifetime, Roth 401k no RMDs now per Secure 2.0.

4 Steps To Use This Roth vs Traditional Comparison Tool

First — Enter pre-tax dollars available to invest. Example $10,000 pre-tax available. This is gross amount before tax you can allocate. If you have $10,000 after-tax cash for Roth, equivalent pre-tax is $10,000/(1-currentRate) = $12,820 at 22%.

Second — Set current vs retirement tax rate. Current example 22% marginal now, retirement example 22% expected at withdrawal. Use marginal rate now vs expected marginal at withdrawal, not effective. If you expect higher income later or higher tax brackets later, set retirement higher.

Third — Add return and years to grow. Return example 7% annual average for 60/40 or S&P 500 long-term, years example 30 years to retirement. Growth factor (1.07)^30=7.612.

Fourth — Compare future after-tax. Hit Compare Roth vs Traditional. See Traditional future before tax = contribution×(1+r)^n, Traditional after-tax = before×(1-retireRate), Roth after-tax invested = contribution×(1-currentRate), Roth future tax-free = after-tax invested×(1+r)^n, tax savings now = contribution×currentRate for Traditional, difference = Roth future - Traditional after-tax, winner, breakeven retirement rate = current rate.

Behind The Math — How We Calculate Future After-Tax

Source: IRS Publication 590 IRA, IRS 401k limits, compound growth formula Future = Present×(1+r)^n.

Growth Factor = (1 + Return%)^Years
Traditional Before Tax = Contribution × Growth Factor
Traditional After-Tax = Traditional Before Tax × (1 - RetireRate%)
Tax Savings Now = Contribution × CurrentRate% (Traditional saves)
Roth Invested After-Tax = Contribution × (1 - CurrentRate%)
Roth Future Tax-Free = Roth Invested × Growth Factor
Difference = Roth Future - Traditional After-Tax
Breakeven RetireRate = CurrentRate% | If RetireRate > CurrentRate Roth wins | If RetireRate < CurrentRate Traditional wins

Verification with $10,000 contribution 22% current 22% retire 7% 30 years:

• Growth factor (1.07)^30=7.612255, Traditional before $10k×7.612255=$76,122.55
• Traditional after-tax $76,122.55×(1-22%)=$76,122.55×0.78=$59,375.59
• Tax savings now $10k×22%=$2,200 Traditional saves now
• Roth invested after-tax $10k×(1-22%)=$7,800, Roth future $7,800×7.612255=$59,375.59 tax-free same as Traditional when rates equal
• Difference $0 breakeven

Verification with $10,000 contribution 22% current 28% retire 7% 30 years:

• Traditional before $76,122.55 after-tax $76,122.55×(1-28%)=$76,122.55×0.72=$54,808.24
• Roth future $59,375.59, Difference $59,375.59-$54,808.24=$4,567.35 Roth wins by $4,567 when retire higher

Guards: rates 0-50% capped, return 0-15% capped, years 1-60 capped, contribution floor 0, non-finite→0, growth factor at least 1.

What Each Result Tells You — Only What Matters

Traditional Future Before Tax: Contribution times growth factor. Example $10k×7.612=$76,122 before tax.

Traditional After-Tax: Before tax times (1 - retire rate). Example $76,122×0.78=$59,375 at 22% retire rate.

Roth Invested After-Tax: Contribution times (1 - current rate) after paying tax now. Example $10k×0.78=$7,800 invested after paying $2,200 now.

Roth Future Tax-Free: After-tax invested times growth factor tax-free. Example $7,800×7.612=$59,375 tax-free.

Tax Savings Now: Contribution times current rate Traditional saves now. Example $10k×22%=$2,200 savings now for Traditional, Roth pays $2,200 now.

Difference & Winner: Roth future minus Traditional after-tax. Positive Roth wins, negative Traditional wins, zero tie when rates equal. Example 22% now 28% retire difference $4,567 Roth wins.

Breakeven Retirement Rate: Current rate is breakeven. If retirement rate higher than current Roth wins, if lower Traditional wins.

Examples — Same Contribution Different Tax Rate Scenarios

Base: $10,000 pre-tax 22% current 22% retire 7% 30 years → Growth factor 7.612 Traditional before $76,122 after-tax $59,375 Roth invested $7,800 future $59,375 tie difference $0 breakeven 22%.

Current 22% retire 28% higher later: Traditional before $76,122 after-tax $54,808 Roth future $59,375 difference $4,567 Roth wins $4,567 more after-tax due to higher retirement rate.

Current 22% retire 12% lower later: Traditional before $76,122 after-tax $66,987 Roth future $59,375 difference -$7,612 Traditional wins $7,612 more after-tax due to lower retirement rate.

Current 12% retire 22% higher later low income now: Contribution $10k Growth 7.612 Traditional before $76,122 after-tax $59,375 at 22% retire Roth invested $10k×(1-12%)=$8,800 future $66,987 Roth wins $7,612 when current low retire high ideal for young earners.

Current 32% retire 22% lower later high income now: Contribution $10k Traditional before $76,122 after-tax $59,375 Roth invested $10k×0.68=$6,800 future $51,763 difference -$7,612 Traditional wins $7,612 when current high retire low ideal for peak earning years.

Split 50/50 $10k total: $5k Traditional $5k Roth current 22% Traditional $5k before $38,061 after-tax $29,687 Roth $5k after-tax invested $3,900 future $29,687 total $59,375 same as all Traditional or all Roth when rates equal but diversifies tax risk.

Common Pitfalls To Avoid

1. Comparing $10k Roth vs $10k Traditional as equal out-of-pocket: $10k Roth after-tax costs $12,820 pre-tax at 22% vs $10k Traditional pre-tax costs $10k pre-tax. To make equal pre-tax dollars Roth $10k after-tax invested should compare to Traditional $12,820 pre-tax if you have $10k after-tax cash. Our calculator uses pre-tax available for apples to apples.
2. Using effective rate instead of marginal: Use marginal rate now vs expected marginal at withdrawal, not effective. Contribution saves at marginal now, withdrawal taxed at marginal later for last dollars, not average.
3. Ignoring RMDs and Social Security taxation: Traditional RMDs starting age 73 force taxable income that may push Social Security taxable and Medicare IRMAA higher. Roth no RMDs IRA avoids that forced income. Example $500k Traditional RMD about $18k at 73 adds to taxable.
4. Forgetting employer match is always Traditional: Employer match even if you choose Roth 401k is pre-tax Traditional bucket. Example you contribute Roth $5,100 after-tax match $2,550 pre-tax Traditional separate taxed later, not Roth.
5. Not considering state tax change: Moving from California 9.3% to Texas 0% at retirement lowers retirement rate, Traditional wins. Moving opposite Roth wins. Include state in current vs retirement rate estimate.

Smart Move — How To Use This Comparison Practically

If current rate lower than expected retirement rate — young earner, low income year, sabbatical — choose Roth now pay tax low now for tax-free later. Example current 12% retire 22% Roth wins $7,612 on $10k 30 years. If current rate higher than expected retirement rate — peak earning years, high bracket — choose Traditional now save tax high now. Example current 32% retire 22% Traditional wins $7,612. If rates equal, after-tax future equal mathematically, choose split for tax diversification 50/50 to hedge future tax law changes. Contribute enough Traditional to drop to lower bracket then Roth for rest — example $85k single taxable $70k bracket 22% starts at $48,476 contribute Traditional $21,524 to drop to 12% bracket save 22% on that portion, then Roth rest at 12% low rate ideal. Consider backdoor Roth if income over IRA limit — contribute non-deductible Traditional then convert to Roth per pro-rata rule. Keep Roth for estate — Roth IRA no RMDs and heirs get tax-free growth 10 years per Secure Act.

Key Caveats

This tool provides estimates for educational purposes only. Not tax, financial, or legal advice. Results depend on inputs you provide. Tax rates, brackets, return, RMD age 73, IRA 401k limits and rules change. Does not include state tax nuances, early withdrawal penalties 10% before 59.5, pro-rata rule for backdoor Roth, Social Security taxation, Medicare IRMAA, or detailed Schedule D. Return is assumed constant annual average, actual market varies. Verify with IRS Publication 590, IRS 401k rules, plan documents and tax advisor. Inputs are processed in your browser and not sent to a server for this calculator component.

Frequently Asked Questions

What is difference between Roth and Traditional?

Traditional IRA 401k contribution pre-tax reduces taxable now, grows tax-deferred, taxed at withdrawal at retirement rate. Roth contribution after-tax no deduction now, grows tax-free, no tax at withdrawal. Example $10k pre-tax Traditional saves $2,200 now at 22% current, Roth pays $2,200 now.

When does Roth beat Traditional?

Roth beats when retirement tax rate higher than current rate. Example current 22% retirement 28% Traditional $10k grows to $46,901 at 7% 30 years after-tax $33,769 at 28% vs Roth $7,800 after-tax invested grows to $36,583 tax-free Roth wins $2,814.

What is breakeven retirement tax rate?

Breakeven is current rate. If retirement rate = current rate after-tax future equal. Example both 22% Traditional $10k future $76,122 before tax after-tax $59,375 Roth $7,800 after-tax future $59,375 same. If retirement lower than current Traditional wins.

Does employer match affect Roth vs Traditional?

Employer match always pre-tax Traditional even if you choose Roth. Example you contribute Roth 6% $5,100 after-tax employer match 3% $2,550 pre-tax Traditional separate bucket taxed at withdrawal.

What about RMDs?

Traditional IRA 401k has required minimum distributions RMDs starting age 73, Roth IRA no RMDs during owner lifetime, Roth 401k no RMDs now. RMDs force taxable income later may push to higher bracket.

Can I split between both?

Yes. Many split 50% Traditional 50% Roth for tax diversification. Example $10k total $5k Traditional saves $1,100 now at 22% plus $5k Roth after-tax $3,900 invested for tax-free future.

What is backdoor Roth?

Backdoor Roth for high income over IRA deduction limit: contribute non-deductible Traditional IRA then convert to Roth. Pay tax on growth only if no other pre-tax IRA per pro-rata rule.

Does this calculator save data?

No. Calculation runs in your browser. Inputs are not sent to a server for this calculator component. Closing tab clears values.