Updated August 3, 2026. Quick answer: the 457(b) special catch-up lets you defer up to twice the normal limit in the three years before your plan’s normal retirement age — but only to the extent you under-contributed in earlier years. And in any year you use it, the age-50 catch-up does not apply at all. They are an either/or, by statute.
The formula, exactly as written
457(b)(3) sets the ceiling for those years at the lesser of:
- (A) twice the dollar amount in effect under 457(b)(2)(A), or
- (B) the normal ceiling for the year plus “so much of the plan ceiling … for taxable years before the taxable year as has not previously been used.”
Limb (B) is the one that gets left out of every summary. The doubled figure is a cap, not an entitlement: you can only catch up on room you actually left unused. A worker who maxed the plan every year has no unused ceiling and therefore gets no special catch-up at all — limb (B) is zero above the normal $24,500.
The coordination rule people get wrong
A governmental 457(b) is an “applicable employer plan” for the age-50 catch-up (414(v)(6)(A)(iii)), so in ordinary years the age-50 catch-up is available. But 414(v)(6)(C) is explicit: “This subsection shall not apply to a participant for any year for which a higher limitation applies to the participant under section 457(b)(3).”
You take whichever is larger, never both. In a special-catch-up year the age-50 catch-up switches off entirely by operation of statute — it is not added on top, and a plan cannot let you stack them.
Working out whether it is worth using
Two comparisons. First, is limb (B) actually bigger than $24,500 + $8,000 (or + $11,250 at ages 60 to 63)? If you have little unused room, the ordinary age-50 catch-up wins and the special catch-up is worse. Second, what does your plan define as normal retirement age? The three-year window is measured against the plan’s definition, not against 65 or your pension’s full-benefit age, and plans differ.
You will need your deferral history to compute unused ceiling. Most plan administrators will calculate it for you on request, and it is worth asking early: the window is three years wide and it does not reopen.
Related: funding both plans · why catch-up sits outside 415(c).
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Penalty and limit statements on this page are read from the Internal Revenue Code itself (26 U.S.C. 72, 402, 414, 457 and 4974) and from IRS Notice 2025-67 for the 2026 figures. General information, not tax advice; your plan document can be more restrictive than the Code, and it governs what your plan actually allows.