Boston, April
Boston Marathon Pacing Plan
A point-to-point net-downhill course from Hopkinton to Boston's Back Bay — but the net drop hides a brutal middle: the Newton hills start around mile 16 and climax with Heartbreak Hill at mile 20-21, arriving right when glycogen stores are lowest. Wellesley College's 'Scream Tunnel' around the halfway mark is famous for being audible nearly a mile away in either direction.
Distance
26.4 mi
Elevation gain
+97m / -231m
Typically run in
April
Typical race-day weather
49°F, 8 mph
Weather is a 10-year seasonal average for this course's location and month, not a forecast for a specific date — see FAQ.
Elevation profile
Sample strategy — 3:45:00 goal
A real, AI-generated excerpt of what Splitsmith produces for this exact course — not a hand-written example. Upload your own goal and recent results to get the full plan.
KM 0-6 — The first six kilometers drop net downhill (grade eases from -3.6% at the start to -2.1% by km5), and the data confirms it: km1 clocks 4:24/km, km5 4:47/km, km6 4:58/km — all noticeably faster than your 5:18/km average pace. Resist running by feel here; hold closer to 5:00-5:10/km even though the descent lets you go quicker. Every second gained on this downhill costs your quads later at the Newton hills, so bank nothing and cross km6 near 29:49 still in control.
KM 7-15 — KM7-15 is rolling and mostly flat, with paces settling between 5:10 and 5:30/km as small grade changes (+0.6% at km7, +0.5% just ahead at km16) nudge you slightly slower than average. Run by effort, not urgency — this stretch is where the race quietly evens itself out after the fast downhill start. You should cross km15 near 1:17:39; if your watch reads meaningfully faster than that, ease off now.
KM 16-24 — Grade stays mild through km16-24 but leans persistently uphill (km16-18 at +0.2 to +0.5%, km23-24 back to +0.2 to +0.5%), which is why pace drifts to 5:24-5:30/km even at honest effort. Use the brief downhill dip at km19 (-1.1%, 5:02/km) to recover, not to surge. You'll pass the half in this stretch — expect roughly 1:49:39 at km21 — and it should feel slightly conservative, not smooth.
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Build my Boston Marathon plan →Splitsmith is an independent pacing-plan tool and is not an official partner, sponsor, or affiliate of the Boston Marathon or its organizers. Course data source: digitized from the official course.