Will the Downhill Index Lower the 2027 Cutoff?

Published September 16, 2026 · Estimates, updated each registration cycle

Short answer: probably yes, a little, but nobody can say how much, and it is not a reason to feel safe on a thin buffer. The 2027 race is the first to apply a downhill index, and qualifier registration closes at 5:00 p.m. Eastern on Friday, September 18, 2026. Our central estimate for the cutoff is still about 5:15, with a realistic range of roughly 3:30 to 7:00.

What the index does to the applicant pool

The cutoff is not a target the BAA picks. It is the byproduct of sorting every accepted application by buffer and drawing a line where the field fills. So anything that changes the shape of the applicant pool changes the cutoff, and the index changes it in exactly one direction: it makes some fast times slower on paper.

The tiers are published. A course with a net drop of 1,500 to 2,999 feet adds 5:00 to the submitted time. A drop of 3,000 to 5,999 feet adds 10:00. A course dropping 6,000 feet or more cannot be used to qualify at all. For the full breakdown of which races cross the line, see which marathons are too downhill for Boston 2027 and the rule explained.

Picture the pool as a queue sorted by buffer. Every runner who qualified on a REVEL race or St. George moves five or ten minutes back in that queue. Some of them drop out of qualifying range entirely and never apply. The runners ahead of them do not move, but the line that fills the field now falls further down a queue that has lost part of its fast front end. That is downward pressure on the cutoff.

Why the effect is smaller than it sounds

Three things blunt it. First, steep downhill qualifiers are a visible minority, not a majority: they dominate running forum conversation far more than they dominate the field. Second, the rule was announced well before registration, so many runners who would have used a downhill time simply ran a different qualifier instead, and that time is in the pool at full value. Third, a lower cutoff makes Boston look more attainable, which over time pulls in more applicants and pushes the cutoff back up.

There is also a counterweight inside the same announcement. The new Boston Qualifier Selection hands about 1,000 places to randomly drawn applicants who did not beat the cutoff. Those places come out of the same field size, so roughly a thousand fewer spots are filled strictly by buffer. On its own that pushes the cutoff up, not down.

What this means for your application

If you qualified on a flat or rolling course, the index is mild good news and nothing more. Treat 5:15 as your planning number, not 3:30. For reference, the 2026 race settled at 4:34 and the 2025 race at 6:51, so a year-over-year swing of two minutes is ordinary even without a rule change.

If you qualified on a steep course, do the adjustment yourself before you decide how hopeful to be. Add 5:00 or 10:00 to your finish time, then run that adjusted number through the cutoff predictor. The tool works from the time you enter and does not apply the index for you, so an unadjusted downhill time will read as more optimistic than your real position.

Either way, the decision is unchanged while registration is open: if you hold a qualifying time, apply. There is no penalty for applying and missing, the entry fee is only charged on acceptance, and a submitted application is the only way into the random selection draw. The real number arrives when the BAA notifies applicants in early October.