Parlay math, made obvious
Stack legs,
measure edge.
ParlayLab is a transparent parlay builder. Type the American odds for each leg and the calculator on the right gives you the combined line, implied probability, and payout per dollar staked — in real time, with no markup.
- Open source
- 100%
- Stake
- $0
- Legs
- 2–10
math is in the page
demo only
add or trim
Parlay calculator
Enter American odds for each leg (e.g. -110, +200).
Combined
+595
6.95 dec
Implied prob
14.4%
odds of hitting
Total payout
$695.45
Profit
+$595.45
Math runs in your browser. Nothing is logged. Demo only — no real wager is placed.
Bench protocol
A leg, taken from moneyline to staked dollar.
Specimen 02 · Chiefs -3.5 @ -110
-
Step 01 · Read
Moneyline
-110
book price as listed
-
Step 02 · Convert
Implied %
52.4%
110 / (110 + 100)
-
Step 03 · Estimate
Fair %
55.0%
your model, sims, or both
-
Step 04 · Stake
EV / $100
+$4.76
Kelly suggests 1.8u
Every leg ParlayLab logs walks this same four-step pipe. If the fair price ≤ the implied price, the lab refuses to sign off on the slip.
Walkthroughs
Three quick demos.
03 / 03
Build a slip from scratch
Open three leg slots. Pick spreads, totals, and props. Watch the combined odds and implied probability calculate in real time.
Open the builder →
See where the edge is
Per-leg probabilities, payout distribution, fair vs market price. Three inline charts cut the math down to plain shapes.
View the breakdown →
Build your own, methodically
Pick legs, check probabilities, see your edge, size the stake. A four-step protocol with a Kelly suggestion at the end.
Walk the protocol →