Tools · Mega Backdoor Roth
Mega backdoor Roth
capacity.
If your 401(k) plan allows after-tax contributions and in-service rollovers, you can shelter tens of thousands more per year in a Roth wrapper than the standard limit. This tool shows your remaining capacity.
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This page covers US-specific 401(k) rules. The mega backdoor Roth is unique to the US 401(k) / 403(b) / solo 401(k) structure. It does not exist in other countries' workplace retirement systems.
Age 50+ unlocks catch-up contributions.
2026 limit: $24,500 ($32,000 with 50+ catch-up).
Check with your plan administrator whether both (a) after-tax contributions are allowed, and (b) in-service rollovers or in-plan conversions are allowed. Without both, the mega backdoor is not available.
YOUR MEGA BACKDOOR CAPACITY
$0
per year of additional tax-free savings room.
TOTAL 401(K) LIMIT
$72,000
YOUR CONTRIBUTION
$0
EMPLOYER MATCH
$0
REMAINING CAPACITY
$0
LIFETIME IMPACT
Enter values to see projection.
What this tool assumes
- 2026 total 401(k) contribution limit (415(c)): $72,000; catch-up at 50+ adds $7,500 for $80,500 total.
- 2026 employee elective-deferral limit (402(g)): $24,500; catch-up at 50+ adds $7,500 for $32,000 total.
- Mega backdoor is only possible if your plan allows after-tax contributions and in-service conversions or rollovers.
- After-tax contributions can exceed the employee contribution limit up to the total plan limit.
- In-service rollover or in-plan conversion moves after-tax dollars to Roth immediately; earnings before the conversion are taxable.
The mega backdoor Roth is one of the most powerful retirement tools available to US W-2 employees. Educational only; not financial advice.