FA-59053 / Payroll withholding rules / Member archive
401(k) deferral limit with catch-up: remaining room report · case 03
Reported remaining deferral room ignores year-to-date contributions.
Case contract
Input {gross, pct, ytd, birth_year, year, net_available}. Requested deferral = gross*pct/100 half-up. Annual cap 23,000.00 plus 7,500.00 catch-up when the employee turns 50 or older during the year. Deferral = min(request, max(0, cap - ytd), net_available). Return [deferral, remaining room after it].
Why this case matters
Deferral limits apply to the calendar year of the age milestone and cannot exceed pay available after taxes.
One recorded failure
Sample boundary fixtureThis sample comes from the broken implementation of a controlled reproducer.
| Boundary fixture | Actual | Expected | Outcome |
|---|---|---|---|
| regression 0 | [1523, 2298477] | [1523, 51988] | Failed |
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