What's a Good Bonus Bet Conversion Rate? The Math Behind 70% to 80%
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Key takeaways
- Conversion rate = locked cash ÷ bonus amount. With no margin at all, the ceiling is 1 − 1 ÷ promo decimal odds.
- Market margin eats into the rate, and the damage grows with the odds. The best conversions come from long odds where two books disagree, most often on alternate totals and spreads.
- Hedge cash needed rises steeply with odds: a $100 bonus at +500 needs over $400 of hedge.
- 70% is a solid conversion. 80%+ usually means you found two books that disagree.
When people talk about converting bonus bets, the number they quote is the conversion rate: how many cents of withdrawable cash you get for each dollar of bonus. A 75% conversion on a $200 bonus means $150 in your pocket.
This guide explains where that number comes from, why it tops out around 80% in practice, and how to pick odds that land near the top of the range without tying up all your cash.
The formula
For a bonus bet of size B at decimal odds d₁, hedged at decimal odds d₂:
Two things drive the result: how long the promo odds are and how much margin the two prices share. It’s easiest to see them separately.
The ceiling: conversion with zero margin
Imagine a perfectly fair market where the two prices’ implied probabilities add up to exactly 100%. Then the formula simplifies to:
| Promo odds | Decimal | Maximum conversion |
|---|---|---|
| +100 | 2.00 | 50.0% |
| +200 | 3.00 | 66.7% |
| +300 | 4.00 | 75.0% |
| +400 | 5.00 | 80.0% |
| +500 | 6.00 | 83.3% |
| +1000 | 11.00 | 90.9% |
The pattern comes from the stake the sportsbook keeps. At +100, half of a winning bet’s total return would be stake, so you can never capture more than half the bonus. At +1000, the stake is under a tenth of the return.
The reality: margin makes longshots worse
Real markets have margin. Say the two prices you pick add up to a combined implied probability of I (for example 102% or 104%). The conversion rate becomes:
The margin term gets multiplied by (d₁ − 1), so every extra percent of margin costs more at longer odds. Here’s what that looks like:
| Promo odds | Tight pair (102%) | Typical pair (104%) | Hedge per $100 of bonus (102%) |
|---|---|---|---|
| +100 | 48.0% | 46.0% | $52 |
| +200 | 62.7% | 58.7% | $137 |
| +300 | 69.0% | 63.0% | $231 |
| +400 | 72.0% | 64.0% | $328 |
| +500 | 73.3% | 63.3% | $427 |
| +700 | 73.5% | 59.5% | $627 |
| +1000 | 70.9% | 50.9% | $929 |
Three things stand out:
- Margin matters more than odds. The difference between a 102% pair and a 104% pair at +500 is ten percentage points of conversion.
- The best odds depend on the margin. With a tight pair, anything from +300 to +700 converts well. With a typical pair, the peak is around +300 to +400.
- Hedge cash grows fast. At +700 you need more than six times the bonus in hedge money.
On main lines, longshot prices usually carry more margin than favorites, which pulls the best conversions back toward the +250 to +600 range. Alternate lines are the big exception.
Alternate lines: where 80%+ conversions live
Alternate totals and spreads far from the main line are often priced by each sportsbook’s own formula, and those formulas disagree. The best over at one book and the best under at another can add up to barely more than 100%, even at +800 or longer. That’s the tight pair you want, at the long odds that convert best.
Here’s what that looks like for a $50 bonus bet on NFL alternate totals, with the over at the promo book and the under at a different book:
| Alternate total | Hedge needed | Cash locked | Conversion | Combined market |
|---|---|---|---|---|
| Over at +900 / Under at −950 | $407.14 | $42.86 | 85.7% | 100.5% |
| Over at +850 / Under at −900 | $382.50 | $42.50 | 85.0% | 100.5% |
| Over at +800 / Under at −850 | $357.89 | $42.11 | 84.2% | 100.6% |
Two things to watch:
- The hedge is large. At these odds you need seven to eight times the bonus in cash. A $500 bonus would need around $4,000 of hedge.
- The lines must match exactly. Same game, same number (Over 61.5 against Under 61.5), and the same settlement rules at both books.
Run the numbers: How much cash can I lock in from this bonus bet or no-sweat promo? Open the Bonus Bet Converter
How to find tight pairs
A “tight pair” means the best price on one side at the promo book plus the best price on the other side anywhere else adds up to close to 100%. To find them:
- Compare the promo book’s price with every other book you hold. The hedge only needs to be the best available price, not the same book every time.
- Look where books disagree. Books that move slowly or shade toward popular teams create gaps. Big-favorite markets in the NBA, NHL, and MLB are common hunting grounds.
- Use alternate lines. Alt spreads and totals let you pick a price range, which widens your options.
- Check at different times. Opening lines and the hours before tip-off often show the widest disagreements.
This search is exactly what promo conversion software automates: it pulls prices from every book in your state and ranks each pairing by conversion rate for your specific bonus amount.
Let software find the hedge for every promo
ProfitDuel's Promo Converter scans the books in your state and tells you which market to use for each bonus bet, no-sweat bet, or deposit match, plus exactly how much to hedge.
Start the $1 ProfitDuel trialAffiliate link. The $1, 3-day trial applies to ProfitDuel's Starter plan as listed in September 2026. 21+ and in states where online sports betting is legal.How much cash do you need?
The hedge per $100 column tells the story. To convert a $1,000 bonus at +400 with a 102% pair, you need about $3,280 of cash at the hedge book. If you don’t have that, you have two options:
- Take shorter odds. At +200 the same bonus needs about $1,370 and converts around 63%.
- Split the bonus, if the book allows it, and convert the pieces over several days as hedge winnings come back.
Remember that hedge money is only tied up until the game settles. A bankroll of $1,500 to $2,500 lets most people convert typical welcome offers at good rates. Our bankroll guide covers this in more depth.
What counts as a good conversion?
| Conversion rate | What it means |
|---|---|
| Under 60% | Acceptable if the bonus is about to expire. Otherwise keep looking. |
| 60% to 70% | Typical, especially at shorter odds or with limited books. |
| 70% to 80% | Strong. You found a good pair at sensible odds. |
| 80%+ | Excellent. Usually two books disagreeing, or a near-arbitrage. |
Aim for 70% and don’t agonize over the last couple of points. The real limit on your profit isn’t the conversion rate. It’s how many promos you can claim before your accounts dry up, which we cover in why sportsbooks limit winners.
Frequently asked questions
Is 60% a bad conversion rate?
It’s below average but not a disaster. A 60% conversion on a bonus that expires tomorrow beats a 75% conversion you never get around to. If time allows, look for markets where the combined implied probability of your two prices is closer to 100%.
Why do some people report 90%+ conversions?
Occasionally two books disagree by enough that the pairing is close to an arbitrage on its own, and a very long bonus bet on top of that can convert above 85%. These are rare and usually short-lived.
Should I split a big bonus bet into smaller ones?
If the book allows it, smaller tokens let you use longer odds without a massive hedge and spread the risk of one market going wrong. They also mean more bets to place and track.
Let software find the hedge for every promo
ProfitDuel's Promo Converter scans the books in your state and tells you which market to use for each bonus bet, no-sweat bet, or deposit match, plus exactly how much to hedge.
Start the $1 ProfitDuel trialAffiliate link. The $1, 3-day trial applies to ProfitDuel's Starter plan as listed in September 2026. 21+ and in states where online sports betting is legal.