Don't just run the race.
Outsmart it.
Upload your course or pick your marathon. Splitsmith turns the elevation profile, race-day weather and your fitness into a km-by-km pacing strategy — with a printable pace band and Garmin export.
Free preview — first 30% of your race, up to 10K · No account needed to start
Your race has a shape. Your pacing should too.
Even splits fail on real courses. Splitsmith models the hills, the wind and the late-race fade — before the gun goes off.
Pick your course
Choose from 20 major races with verified elevation profiles, or upload any GPX file.
Set your goal
Target time plus a recent result. We check it's realistic — and tell you if it isn't.
Get your strategy
Split-by-split pacing (min/km or min/mi — auto-set by your race, switchable anytime) adjusted for gradient and race-day forecast, with coach-style notes on where the race is won and lost.
Take it with you
Works with every watch: printable pace band, a lock-screen card, a Garmin course export, and copy-in guides for COROS and Apple Watch.
Not just numbers. A strategy.
A sample from the founder's own Frankfurt Marathon sub-3 plan:
KM 0–5 — The start is crowded and flat. Everyone around you is going out too fast. Sit at 4:18/km, a few seconds slower than goal pace. You'll bank nothing here and that's the point.
KM 28–34 — The quiet grind through Niederrad. No crowds, no landmarks — this is where a 3:02 stays a 3:02. Lock onto 4:14 and take the field back one runner at a time.
KM 40–42.2 — Forecast says 11°C and calm. Empty the tank at 4:08 — the finish is indoors, on the red carpet of the Festhalle. Arrive with nothing left.
Cheaper than a pair of socks. Worth minutes.
One bad pacing decision costs more than this.
Race Pass
- Full km-by-km pacing strategy + AI race notes
- What-if scenarios & goal adjustments for your race
- Weather re-checks until race day (incl. 48h forecast update)
- Printable pace band + lock-screen card
- Garmin course export + COROS/Apple Watch guides
Racing a full season? A multi-race Season Pass is coming — start with your next race for now.
Why I built this. I ran 3:02 in Warsaw. Two minutes and change from sub-3 — the kind of gap you don't close with more training, you close with a smarter race. I'm building Splitsmith for my own sub-3 attempt in Frankfurt, and every plan it generates is the plan I'll be racing with. I'm user #1.
FAQ
How is this different from Garmin PacePro?
PacePro adjusts for elevation only, with generic settings. Splitsmith also models race-day weather, realistic late-race fade, and your recent fitness — and explains the strategy in plain language, so you know why each split is what it is.
Miles or kilometers?
Both. The default follows your race (US and UK races show min/mi, the rest min/km) and you can switch anytime. Pace bands and PDFs come in whichever unit you pick.
My race isn't listed.
Upload the GPX (every race publishes one, or grab it from last year's Strava activities) and you'll get the same full plan.
What if the weather forecast changes?
Engine recalculation — splits re-solved for the latest forecast, including the reliable 48-hours-out window — is unlimited and free for the life of your plan. AI narrative regeneration (the written race-day notes) has a soft limit of 5 per plan.
Is this a subscription?
No. A Race Pass is a one-time $9 purchase for one race — no recurring charges, nothing to cancel. If you race often, a multi-race Season Pass is in the works.
Do you need access to my Strava?
No — a recent race result typed in is enough. Connecting Strava (via the official MCP connector) just makes the goal-check smarter. Your data is only ever shown to you.
Is a goal time really predictable?
No model owns race day. Splitsmith gives you the highest-probability strategy for your goal — and warns you honestly when a goal doesn't match your recent results.