01 Step one
Pick your legs.
Choose 2–5 selections you'd consider on their own merit. If you wouldn't bet a leg straight, it doesn't belong in a parlay.
L1 Chiefs -3.5
selected L2 Cel/Hea O 218.5
selected L3 Ohtani 1+ HR
selected Protocol
Build your parlay in four steps.
A precise, repeatable workflow. Each step has its own measurement. No vibes, only math.
02 Step two
Check implied probabilities.
Convert each leg's American odds into a percentage. This is what the market thinks. Negative odds → |odds| / (|odds| + 100). Positive odds → 100 / (odds + 100).
Chiefs -3.5 -110 · 52.4%
Cel/Hea O 218.5 +110 · 47.6%
Ohtani 1+ HR -140 · 58.3%
03 Step three
See your edge.
Multiply your fair probabilities to get the true probability of the parlay. Compare to the market's combined implied probability. A positive gap is your edge.
Market combined
14.5%
+595
Your true
18.6%
+439 fair
Edge: +28.2%
04 Step four
Decide your stake.
Use the Kelly criterion to size the bet to your edge. Full Kelly is aggressive — quarter Kelly is sane. The output is a percentage of bankroll, not a fixed dollar amount.
Kelly recommendation
Full Kelly
4.7%
Half
2.4%
Quarter
1.2%
On a $1,000 bankroll, that's $47, $24, or $12. Smaller is safer — variance on parlays is severe, and Kelly assumes your fair probabilities are correct.
Ready
Run the protocol on a live slip.
Open the builder, see the math update per leg, and inspect the EV breakdown for any 3-leg combination.