PROLINE

How much does PROLINE keep? Margin vs sportsbooks

Enter the prices of one PROLINE event to see its margin: the chances added up, minus one whole. Then compare a sportsbook on the same game and the same market type.

Example: change any number

Outcomes
Lottery line
Sportsbook line
Show odds as

Lottery line keeps

8.2%

Sportsbook line keeps

3.5%

Bet $100 on every outcome so each one pays the same: the lottery line gives back $91.76, the sportsbook line $96.50.

OutcomeLotterySportsbook$10 pays
Home fair 42.9%2.102.25$21.00 vs $22.50
Tie fair 23.3%4.004.15$40.00 vs $41.50
Away fair 33.9%2.752.85$27.50 vs $28.50

Fair chances are from the sportsbook line with its margin removed in proportion.

Ticket margin by number of picks

  1. 1 pick8.2% vs 3.5%
  2. 2 picks15.8% vs 6.9%
  3. 3 picks22.7% vs 10.1%
  4. 4 picks29.1% vs 13.3%
  5. 5 picks35.0% vs 16.3%
  6. 6 picks40.3% vs 19.3%
  7. 7 picks45.2% vs 22.1%
  8. 8 picks49.7% vs 24.8%

Red: lottery line, blue: sportsbook line. Each pick taken from a market like this one.

How it is calculated
  • Booksum = sum of 1 ÷ price over all outcomes. Lottery: 108.98%, sportsbook: 103.63%.
  • The line keeps 1 − 1 ÷ booksum of the money spread over all outcomes.
  • With k picks: 1 − (1 ÷ booksum) to the power k.
Woman cutting a thin strip off a paper slip with scissors

Measure the margin of one event

  1. Pick one event and marketTake one game and one market type, for example the 3-way line: home, tie, away.
  2. Write down every priceUse decimal prices, for example 2.40, 4.20 and 2.70. PROLINE calculates payouts on decimal odds, whatever format is shown.
  3. Turn prices into chancesDivide 1 by each decimal price. The result is the chance that price implies.
  4. Add the chancesHere the total is 102.5%. Fair chances would add up to exactly one whole.
  5. Take the extra partEverything above one whole is the margin: 2.5%. The share of each dollar the book keeps is a little smaller: margin ÷ total.
  6. Repeat on the sportsbookUse the same game, the same market type and the same time frame. Then compare the two margins.

The margin formula

Margin = (1 ÷ price A + 1 ÷ price B + 1 ÷ price C) minus one

Example: Prices 2.40, 4.20 and 2.70: chances add up to 102.5%, so the margin is 2.5%.

Compare the same market type

3-way line (1X2)

  • Three outcomes: home, tie (X), away.
  • Add three chances to get the margin.
  • Compare only with another 3-way line. See the 60-minute line.
  • Example: chances total 102.5%, margin 2.5%.

2-way line (moneyline)

  • Two outcomes, no tie to pick.
  • Add two chances to get the margin.
  • On PROLINE, Draw No Bet (moneyline) is void if the game ends in a draw.
  • Example: 52.4% + 52.4% = 104.8% (rounded); the exact margin is 4.76%.
  • Share kept: 4.55%, or $4.55 per hundred dollars staked.

More legs, bigger share kept

TicketShare of stakes the book keeps
Single bet4.55%
Two-leg parlay8.9%
Three-leg parlay13.0%
Four-leg parlay17.0%

Each leg here keeps 4.55% (a 52.4% + 52.4% = 104.8% line). Kept share = one minus (one minus 4.55%) to the power of legs. Two legs: 8.9%.

Check other prices

Margin calculator

Any two- or three-outcome market: the margin and the fair, no-vig price.

Parlay calculator

Multiply the legs of a ticket and see the total price and payout.

Expected value calculator

Compare a price with your own estimate of the chance. It is only as good as the estimate.

How PROLINE works

Tickets, markets and what your ticket pays.

Sources

  • olg.ca /en/proline/proline-game-conditions.html · checked Oct 27, 2026

Questions

Is PROLINE worth it compared with a sportsbook?

This page does not rank them. Measure the margin on the same event and market type on both sides, then compare. Whether you can use a sportsbook depends on the laws of your province; this page is not legal advice.

Are PROLINE odds worse than sportsbook odds?

There is no single answer. Margins differ by event and market. Enter both sets of prices for one game in the margin calculator and compare the two results.

Can I compare a 3-way price with a moneyline price?

Not directly. A 3-way line includes a tie outcome; a moneyline has no tie to pick. Compare 3-way with 3-way and 2-way with 2-way, with the same time frame.

Why does a parlay have a higher margin than a single?

The payout multiplies the decimal odds of every leg. Each leg carries its own margin, so the share kept grows with every leg added.