★ COMPARISONS · 401(K) VS ROTH IRA · X VS Y #262
401(k) wins by $5,709.19. With $7,500.00 a year for 30 years at a 7.00% return, a current rate of 22.00% and a retirement rate of 12.00%, the 401(k) is worth $50,240.88 after tax and the Roth IRA $44,531.69 — a $5,709.19 gap — while the Roth pays $1,650.00 tax now and the 401(k) pays $6,851.03 at withdrawal on $225,000.00 of contributions. Comparison #262 in the Bright Side Kit comparisons library.
Put the same pre-tax dollars in a traditional 401(k) or a Roth IRA — which leaves more after tax at retirement? The calculator works out both after-tax values, the tax paid now versus later, and which account wins — and by how much. Comparison #262 in the comparisons library.
On the defaults — $7,500.00 a year for 30 years at a 7.00% return, a current rate of 22.00% and a retirement rate of 12.00% — the 401(k) is worth $50,240.88 after tax, the Roth IRA is worth $44,531.69 after tax, and the 401(k) wins by $5,709.19. The Roth pays $1,650.00 tax now while the 401(k) pays $6,851.03 at withdrawal, on $225,000.00 of contributions in total.
The whole comparison is the two tax rates. The 401(k) takes the tax off at the end: you put in pre-tax dollars, they grow, and you pay your retirement rate on the whole pot. The Roth takes the tax off at the start: you pay your current rate on the contribution, and the rest grows tax-free. When the two rates are equal, the tax is the same dollars, just paid at different times — the accounts TIE exactly. At a 22.00% retirement rate both are worth $44,531.69; at 12.00% now and 12.00% in retirement both are worth $50,240.88. A lower retirement rate favours the 401(k) — at 12.00% it wins by $5,709.19 — and a higher one favours the Roth — at a 24.00% retirement rate the Roth wins by $1,141.84.
The tax timing is what the two tax figures show. The Roth pays $1,650.00 now — 22.00% of one year’s $7,500.00 contribution — and nothing at withdrawal. The 401(k) pays nothing now and $6,851.03 at withdrawal — 12.00% of the grown $57,091.91 pot. Paying later looks worse in dollars ($6,851.03 against $1,650.00), but the 401(k) keeps the full $7,500.00 growing for 30 years instead of $5,850.00, and that extra growth is worth more than the extra tax.
Setup: $7,500.00 a year, 30 years, 7.00% return, current rate 22.00%, retirement rate 12.00%.
Line 1 — the growth factor. 1.07^30 = 7.612255. One dollar a year grows to $7.612255 over 30 years at 7.00% — and $7,500.00 a year grows to $7,500.00 × 7.612255 = $57,091.91 before tax.
Line 2 — the 401(k) after-tax value. 401(k) = $7,500.00 × 7.612255 × (1 − 0.12) = $57,091.91 × 0.88 = $50,240.88. The 12.00% retirement tax takes $6,851.03 off the grown pot.
Line 3 — the Roth IRA after-tax value. Roth = $7,500.00 × (1 − 0.22) × 7.612255 = $5,850.00 × 7.612255 = $44,531.69. The 22.00% current tax takes $1,650.00 off the contribution before it grows, and nothing is due at withdrawal.
Line 4 — the gap and the taxes. Difference = $44,531.69 − $50,240.88 = -$5,709.19 — 401(k) wins by $5,709.19. Tax paid now (Roth) = $7,500.00 × 0.22 = $1,650.00. Tax paid at withdrawal (401(k)) = $57,091.91 × 0.12 = $6,851.03. Total contributions = $7,500.00 × 30 = $225,000.00. The default result in full: 401(k) $50,240.88, Roth IRA $44,531.69, difference -$5,709.19 — 401(k) wins by $5,709.19; tax now $1,650.00, tax at withdrawal $6,851.03, total contributions $225,000.00.
Line 5 — the rounding convention. Rounding convention: every gap on this page is the difference of the displayed values: each side is rounded to cents first, then subtracted. On these defaults the unrounded gap and the displayed gap agree at -$5,709.19, but on other inputs they can differ by a cent, and the page always shows the displayed figure.
Retirement rate 22%: 401(k) $44,531.69, Roth IRA $44,531.69, difference $0.00 — TIE; tax now $1,650.00, tax at withdrawal $12,560.22, total contributions $225,000.00. When the retirement rate equals the current rate of 22.00%, the tax is the same dollars paid at different times — the two accounts are worth exactly the same.
Retirement rate 24%: 401(k) $43,389.85, Roth IRA $44,531.69, difference $1,141.84 — Roth IRA wins by $1,141.84; tax now $1,650.00, tax at withdrawal $13,702.06, total contributions $225,000.00. Two points above the current rate is enough to flip the winner — the 401(k)’s withdrawal tax climbs to $13,702.06 and the Roth’s pay-now-and-never-again wins.
Current rate 12%, retirement rate 12%: 401(k) $50,240.88, Roth IRA $50,240.88, difference $0.00 — TIE; tax now $900.00, tax at withdrawal $6,851.03, total contributions $225,000.00. Equal rates tie at any level — here the tie is worth $50,240.88, because the low 12.00% rate leaves more of the pot in both accounts.
Contribution $10,000: 401(k) $66,987.84, Roth IRA $59,375.59, difference -$7,612.25 — 401(k) wins by $7,612.25; tax now $2,200.00, tax at withdrawal $9,134.71, total contributions $300,000.00. A bigger contribution scales the gap up in proportion — the 401(k)’s lead grows from $5,709.19 to $7,612.25 — but remember the Roth IRA limit is $7,500, so the extra $2,500.00 a year could not go into a Roth IRA.
Years 20: 401(k) $25,539.92, Roth IRA $22,637.65, difference -$2,902.27 — 401(k) wins by $2,902.27; tax now $1,650.00, tax at withdrawal $3,482.72, total contributions $150,000.00. Ten fewer years of growth shrinks the gap from $5,709.19 to $2,902.27 — the 401(k)’s advantage is the extra growth on the untaxed dollars, and that advantage needs time to build.
Return 5%: 401(k) $28,524.82, Roth IRA $25,283.36, difference -$3,241.46 — 401(k) wins by $3,241.46; tax now $1,650.00, tax at withdrawal $3,889.75, total contributions $225,000.00. A lower return shrinks both pots — the growth factor falls from 7.612255 to 4.321942 — and with less growth the 401(k)’s lead narrows from $5,709.19 to $3,241.46.
Retirement rate for a TIE: exact 22.0000%; displayed 22.00% → 401(k) $44,531.69, Roth IRA $44,531.69, difference $0.00 — TIE; tax now $1,650.00, tax at withdrawal $12,560.22, total contributions $225,000.00. At 21%: 401(k) $45,102.61, Roth IRA $44,531.69, difference -$570.92 — 401(k) wins by $570.92; tax now $1,650.00, tax at withdrawal $11,989.30, total contributions $225,000.00. At 23%: 401(k) $43,960.77, Roth IRA $44,531.69, difference $570.92 — Roth IRA wins by $570.92; tax now $1,650.00, tax at withdrawal $13,131.14, total contributions $225,000.00. The star is a PERCENT. This reverse is CONTINUOUS — the tie rate is exactly the current rate, because the two accounts tie whenever the rates are equal.
Current rate for a TIE at a 12% retirement rate: exact 12.0000%; displayed 12.00% → 401(k) $50,240.88, Roth IRA $50,240.88, difference $0.00 — TIE; tax now $900.00, tax at withdrawal $6,851.03, total contributions $225,000.00. At 11%: 401(k) $50,240.88, Roth IRA $50,811.80, difference $570.92 — Roth IRA wins by $570.92; tax now $825.00, tax at withdrawal $6,851.03, total contributions $225,000.00. At 13%: 401(k) $50,240.88, Roth IRA $49,669.96, difference -$570.92 — 401(k) wins by $570.92; tax now $975.00, tax at withdrawal $6,851.03, total contributions $225,000.00. The star is a PERCENT. This reverse is CONTINUOUS — the tie rate is exactly the retirement rate, the same equal-rates rule from the other side.
Years for the 401(k) lead to reach at least $5,000: exact 29 years; displayed 29 years → 401(k) $46,954.10, Roth IRA $41,618.40, difference -$5,335.70 — 401(k) wins by $5,335.70; tax now $1,650.00, tax at withdrawal $6,402.83, total contributions $217,500.00. At 28 years: 401(k) $43,882.33, Roth IRA $38,895.70, difference -$4,986.63 — 401(k) wins by $4,986.63; tax now $1,650.00, tax at withdrawal $5,983.95, total contributions $210,000.00. 29 years is the smallest term that reaches a $5,000 lead — 28 years only reaches $4,986.63. The star is YEARS. This reverse is a STEP.
Contribution for a 401(k) lead of exactly $10,000: exact $13136.7117; displayed $13,136.71 → 401(k) $87,999.99, Roth IRA $77,999.99, difference -$10,000.00 — 401(k) wins by $10,000.00; tax now $2,890.08, tax at withdrawal $12,000.00, total contributions $394,101.30. At $13,135.71: 401(k) $87,993.29, Roth IRA $77,994.05, difference -$9,999.24 — 401(k) wins by $9,999.24; tax now $2,889.86, tax at withdrawal $11,999.08, total contributions $394,071.30. At $13,137.71: 401(k) $88,006.69, Roth IRA $78,005.93, difference -$10,000.76 — 401(k) wins by $10,000.76; tax now $2,890.30, tax at withdrawal $12,000.91, total contributions $394,131.30. The star is DOLLARS. This reverse is CONTINUOUS.
Annual return for a 401(k) lead of exactly $5,000: exact 6.5280%; displayed 6.53% → 401(k) $44,025.24, Roth IRA $39,022.37, difference -$5,002.87 — 401(k) wins by $5,002.87; tax now $1,650.00, tax at withdrawal $6,003.44, total contributions $225,000.00. At 6.52%: 401(k) $43,901.43, Roth IRA $38,912.63, difference -$4,988.80 — 401(k) wins by $4,988.80; tax now $1,650.00, tax at withdrawal $5,986.56, total contributions $225,000.00. At 6.54%: 401(k) $44,149.39, Roth IRA $39,132.41, difference -$5,016.98 — 401(k) wins by $5,016.98; tax now $1,650.00, tax at withdrawal $6,020.37, total contributions $225,000.00. The star is a PERCENT. This reverse is CONTINUOUS.
Current rate for the Roth to win by exactly $1,000: exact 10.2484%; displayed 10.25% → 401(k) $50,240.88, Roth IRA $51,239.99, difference $999.11 — Roth IRA wins by $999.11; tax now $768.75, tax at withdrawal $6,851.03, total contributions $225,000.00. At 10.24%: 401(k) $50,240.88, Roth IRA $51,245.70, difference $1,004.82 — Roth IRA wins by $1,004.82; tax now $768.00, tax at withdrawal $6,851.03, total contributions $225,000.00. At 10.26%: 401(k) $50,240.88, Roth IRA $51,234.28, difference $993.40 — Roth IRA wins by $993.40; tax now $769.50, tax at withdrawal $6,851.03, total contributions $225,000.00. The star is a PERCENT. This reverse is CONTINUOUS — the exact rate comes from the unrounded model, and the displayed 10.25% rounds it to the nearest hundredth of a point.
The whole comparison is the two tax rates — when they are equal the accounts TIE exactly (the tax is the same dollars, just paid at different times); a lower retirement rate favours the 401(k), a higher one favours the Roth. The Roth IRA has an income phase-out ($153,000–$168,000 single for 2026 — above it you cannot contribute directly) and a $7,500 annual limit, so above $7,500 the extra dollars would go to a Roth 401(k) or a taxable account, not a Roth IRA. The 401(k) may come with an employer match, which this comparison does NOT model (a match usually beats either account alone). Required minimum distributions apply to the traditional 401(k), not to the Roth IRA. Returns are assumed constant — real returns vary. With a 0.00% return (401(k) $6,600.00, Roth IRA $5,850.00, difference -$750.00 — 401(k) wins by $750.00; tax now $1,650.00, tax at withdrawal $900.00, total contributions $225,000.00) there is no growth, so the comparison is just the tax rates — a model-level outcome, not an error. With 1 year (401(k) $7,062.00, Roth IRA $6,259.50, difference -$802.50 — 401(k) wins by $802.50; tax now $1,650.00, tax at withdrawal $963.00, total contributions $7,500.00) a single year of growth barely moves the gap. With a $24,500.00 contribution (401(k) $164,120.22, Roth IRA $145,470.19, difference -$18,650.03 — 401(k) wins by $18,650.03; tax now $5,390.00, tax at withdrawal $22,380.03, total contributions $735,000.00) the gap scales up — but remember, above the $7,500 Roth IRA limit the extra dollars could not go into a Roth IRA at all. With a 0.00% retirement rate (401(k) $57,091.91, Roth IRA $44,531.69, difference -$12,560.22 — 401(k) wins by $12,560.22; tax now $1,650.00, tax at withdrawal $0.00, total contributions $225,000.00) the 401(k) keeps the whole grown pot. With a 0.00% current rate and a 12.00% retirement rate (401(k) $50,240.88, Roth IRA $57,091.91, difference $6,851.03 — Roth IRA wins by $6,851.03; tax now $0.00, tax at withdrawal $6,851.03, total contributions $225,000.00) the Roth pays no tax at either end and wins by exactly the 401(k)’s withdrawal tax. Rounding convention: every gap on this page is the difference of the displayed values: each side is rounded to cents first, then subtracted.
| Output | Formula | What it means |
|---|---|---|
| Growth factor | (1+r)^N | 7.612255 over 30 years at 7.00%. |
| 401(k) after-tax value | C × F × (1 − t_ret) | $50,240.88 after tax at retirement. |
| Roth IRA after-tax value | C × (1 − t_now) × F | $44,531.69 after tax at retirement. |
| Difference | Roth − 401(k) on displayed values | -$5,709.19. |
| Winner | higher value wins | 401(k) wins by $5,709.19. |
| Tax paid now (Roth) | C × t_now | $1,650.00 paid this year. |
| Tax paid at withdrawal (401(k)) | C × F × t_ret | $6,851.03 paid at retirement. |
| Total contributions | C × N | $225,000.00 over 30 years. |
| Retirement rate for a TIE | exact 22.0000% | 22.00% → 22.00%. |
| At 21% (one step below) | difference at the displayed value | 401(k) $45,102.61, Roth IRA $44,531.69, difference -$570.92 — 401(k) wins by $570.92; tax now $1,650.00, tax at withdrawal $11,989.30, total contributions $225,000.00. |
| At 23% (one step above) | difference at the displayed value | 401(k) $43,960.77, Roth IRA $44,531.69, difference $570.92 — Roth IRA wins by $570.92; tax now $1,650.00, tax at withdrawal $13,131.14, total contributions $225,000.00. |
| Current rate for a TIE | exact 12.0000% | 12.00% → 12.00%. |
| At 11% (one step below) | difference at the displayed value | 401(k) $50,240.88, Roth IRA $50,811.80, difference $570.92 — Roth IRA wins by $570.92; tax now $825.00, tax at withdrawal $6,851.03, total contributions $225,000.00. |
| At 13% (one step above) | difference at the displayed value | 401(k) $50,240.88, Roth IRA $49,669.96, difference -$570.92 — 401(k) wins by $570.92; tax now $975.00, tax at withdrawal $6,851.03, total contributions $225,000.00. |
| Years for a 401(k) lead of at least $5,000 | exact 29.0000 years | 29 years → 29 years. |
| At 28 years (one step below) | lead at the displayed value | 401(k) $43,882.33, Roth IRA $38,895.70, difference -$4,986.63 — 401(k) wins by $4,986.63; tax now $1,650.00, tax at withdrawal $5,983.95, total contributions $210,000.00. |
| At 30 years (one step above) | lead at the displayed value | 401(k) $50,240.88, Roth IRA $44,531.69, difference -$5,709.19 — 401(k) wins by $5,709.19; tax now $1,650.00, tax at withdrawal $6,851.03, total contributions $225,000.00. |
| Contribution for a 401(k) lead of exactly $10,000 | exact $13136.7117 | $13,136.71 → $13,136.71. |
| At $13,135.71 (one step below) | lead at the displayed value | 401(k) $87,993.29, Roth IRA $77,994.05, difference -$9,999.24 — 401(k) wins by $9,999.24; tax now $2,889.86, tax at withdrawal $11,999.08, total contributions $394,071.30. |
| At $13,137.71 (one step above) | lead at the displayed value | 401(k) $88,006.69, Roth IRA $78,005.93, difference -$10,000.76 — 401(k) wins by $10,000.76; tax now $2,890.30, tax at withdrawal $12,000.91, total contributions $394,131.30. |
| Annual return for a 401(k) lead of exactly $5,000 | exact 6.5280% | 6.53% → 6.53%. |
| At 6.52% (one step below) | lead at the displayed value | 401(k) $43,901.43, Roth IRA $38,912.63, difference -$4,988.80 — 401(k) wins by $4,988.80; tax now $1,650.00, tax at withdrawal $5,986.56, total contributions $225,000.00. |
| At 6.54% (one step above) | lead at the displayed value | 401(k) $44,149.39, Roth IRA $39,132.41, difference -$5,016.98 — 401(k) wins by $5,016.98; tax now $1,650.00, tax at withdrawal $6,020.37, total contributions $225,000.00. |
| Current rate for a Roth win of exactly $1,000 | exact 10.2484% | 10.25% → 10.25%. |
| At 10.24% (one step below) | Roth win at the displayed value | 401(k) $50,240.88, Roth IRA $51,245.70, difference $1,004.82 — Roth IRA wins by $1,004.82; tax now $768.00, tax at withdrawal $6,851.03, total contributions $225,000.00. |
| At 10.26% (one step above) | Roth win at the displayed value | 401(k) $50,240.88, Roth IRA $51,234.28, difference $993.40 — Roth IRA wins by $993.40; tax now $769.50, tax at withdrawal $6,851.03, total contributions $225,000.00. |
| Retirement rate 22% | same model | 401(k) $44,531.69, Roth IRA $44,531.69, difference $0.00 — TIE; tax now $1,650.00, tax at withdrawal $12,560.22, total contributions $225,000.00. |
| Retirement rate 24% | same model | 401(k) $43,389.85, Roth IRA $44,531.69, difference $1,141.84 — Roth IRA wins by $1,141.84; tax now $1,650.00, tax at withdrawal $13,702.06, total contributions $225,000.00. |
| Current rate 12%, retirement rate 12% | same model | 401(k) $50,240.88, Roth IRA $50,240.88, difference $0.00 — TIE; tax now $900.00, tax at withdrawal $6,851.03, total contributions $225,000.00. |
| Contribution $10,000 | same model | 401(k) $66,987.84, Roth IRA $59,375.59, difference -$7,612.25 — 401(k) wins by $7,612.25; tax now $2,200.00, tax at withdrawal $9,134.71, total contributions $300,000.00. |
| Years 20 | same model | 401(k) $25,539.92, Roth IRA $22,637.65, difference -$2,902.27 — 401(k) wins by $2,902.27; tax now $1,650.00, tax at withdrawal $3,482.72, total contributions $150,000.00. |
| Return 5% | same model | 401(k) $28,524.82, Roth IRA $25,283.36, difference -$3,241.46 — 401(k) wins by $3,241.46; tax now $1,650.00, tax at withdrawal $3,889.75, total contributions $225,000.00. |
The math is first-principles: the growth factor is (1+r)^N, the 401(k) after-tax value is C × F × (1 − t_ret), the Roth IRA after-tax value is C × (1 − t_now) × F, the tax paid now is C × t_now, the tax paid at withdrawal is C × F × t_ret, and the total contributions are C × N. Every figure is rounded to cents half-up, and every gap is the difference of the displayed values — each side rounded to cents first, then subtracted. What the model cannot do is make the decision for you: the whole answer turns on the two tax rates — at equal rates the accounts TIE exactly, at a 12.00% retirement rate the 401(k) wins by $5,709.19, at a 24.00% retirement rate the Roth wins by $1,141.84. The 401(k) may come with an employer match, which this comparison does NOT model (a match usually beats either account alone). The Roth IRA has an income phase-out ($153,000–$168,000 single for 2026) and a $7,500 annual limit, so above $7,500 the extra dollars would go to a Roth 401(k) or a taxable account, not a Roth IRA. Required minimum distributions apply to the traditional 401(k), not to the Roth IRA. Returns are assumed constant — real returns vary — and state taxes are not modelled. Use this page to compare the two accounts on the same dollars, then check your own rates, your employer match, and the Roth limits before you choose.
Bright Side Kit. "401(k) vs Roth IRA Calculator: Which Wins at Retirement" https://brightoolbox.com/401k-vs-roth-ira/ Accessed October 26, 2026.401(k) wins by $5,709.19. On $7,500.00 a year for 30 years at a 7.00% return, a current rate of 22.00% and a retirement rate of 12.00%, the 401(k) is worth $50,240.88 after tax and the Roth IRA $44,531.69, a difference of -$5,709.19. The Roth pays $1,650.00 tax now, the 401(k) pays $6,851.03 at withdrawal, on $225,000.00 of contributions.
Because the retirement rate (12.00%) is lower than the current rate (22.00%). The 401(k) keeps the full $7,500.00 growing for 30 years and pays 12.00% on the grown $57,091.91 pot — $6,851.03. The Roth pays 22.00% up front, so only $5,850.00 a year grows, and that smaller base ends at $44,531.69. The extra growth on the untaxed dollars is worth more than the extra tax at the end.
Whenever the two tax rates are equal. At a 22.00% retirement rate both are worth $44,531.69, and at 12.00% now and 12.00% in retirement both are worth $50,240.88. The tax is the same dollars, just paid at different times — the 401(k) pays at withdrawal, the Roth pays now.
Anything above 22.00%. The tie rate is exactly the current rate of 22.00%. At a 23.00% retirement rate the Roth wins by $570.92, and at a 24.00% retirement rate it wins by $1,141.84. Below 22.00% the 401(k) wins — at 21.00% it wins by $570.92.
29 years. At 29 years the 401(k) lead is $5,335.70; at 28 years it is only $4,986.63. 29 years is the smallest term that reaches a $5,000 lead — a step reverse, not a continuous one.
$13,136.71 a year (exact $13136.7117). At $13,136.71 the lead is $10,000.00; at $1 less, $13,135.71, it is $9,999.24; at $1 more, $13,137.71, it is $10,000.76. Note the Roth IRA limit is $7,500 a year, so a contribution this large could not go into a Roth IRA at all.
The Roth IRA phases out at $153,000–$168,000 of income for a single filer in 2026 — above it you cannot contribute directly. The annual limit is $7,500, so above $7,500 the extra dollars would go to a Roth 401(k) or a taxable account, not a Roth IRA. The $24,500 edge on this page (401(k) $164,120.22, Roth IRA $145,470.19, 401(k) wins by $18,650.03) is a model-level comparison of the same dollars, not a contribution you could actually make to a Roth IRA.
No. The 401(k) may come with an employer match, which this comparison does NOT model — a match usually beats either account alone, so check your plan before you choose. Required minimum distributions apply to the traditional 401(k), not to the Roth IRA, and returns are assumed constant — real returns vary.