Last updated: July 21, 2026
In Summary
A free bet calculator tells you exactly how to turn a sportsbook bonus bet into real cash you can withdraw, instead of leaving its value on the table. The trick is that most "free bets" only pay you the profit if they win, not the stake, so a $100 bonus bet is never worth a full $100. To capture as much of it as possible, you place the free bet on one side of a market and a real-money hedge on the other side at a second book. Do the math right and you lock in a similar profit regardless of which side wins. A calculator does that math in one click: you enter the free bet amount and the two prices, and it returns the exact hedge stake, the profit you keep, and your conversion rate. OddsShopper's Free Bet Converter is free to use and does this instantly, and the conversion rate is almost always better when you use the bonus bet on longer odds. This guide shows the formula, a full worked example, and the rate to expect.
Watch The Video
In our OddsShopper walkthrough, we take a $50 DraftKings free bet and turn it into cash by betting both sides through the Free Bet Converter — the kind of move that, once it is laid out, makes you think "how come I didn't think of that?" Seeing the hedge stake populate on a real slip is faster than reading the math, so watch it run start to finish before your next bonus lands.
What A Free Bet Calculator Does
A free bet calculator (also called a bonus bet or free bet conversion calculator) answers one question: if I have a bonus bet, what is the most cash I can safely walk away with?
You feed it three things:
- the face value of your free bet (say $100),
- the odds you plan to use the free bet on, and
- the odds on the opposite outcome at another sportsbook, where you will place a real-money hedge.
It returns the hedge amount to bet, the profit you keep either way, and the conversion rate, which is that profit expressed as a percentage of the free bet's face value. This is the same hedging idea behind arbitrage betting, pointed at a bonus instead of a mispriced line.
The reason you need a calculator at all is that the right hedge stake is not obvious, and the answer changes with every price. Get the stake wrong and you are no longer balanced: you end up rooting for one side and gambling part of the bonus instead of banking it.
Why A Free Bet Is Worth Less Than Its Face Value
Most people miss the part that follows. There are two kinds of "free bets," and they are worth very different amounts.
| Type | What you keep if it wins | Roughly worth | What books usually call it |
|---|---|---|---|
| SNR (Stake Not Returned) | Profit only, not the stake | ~60-80% of face | "Bonus bet," "free bet" |
| SR (Stake Returned) | Stake plus profit, like cash | ~100% of face | Rare; true "free bet" / site credit |
Almost every promo a U.S. sportsbook hands out today is an SNR bonus bet. If you place a $100 SNR bonus bet at +100 (decimal 2.00) and it wins, your account does not show $200. It shows $100, because the $100 stake was never yours to keep, only the profit. This is why a $100 bonus bet is realistically worth somewhere in the $60 to $80 range once you convert it, not a clean $100.
Knowing which kind you hold matters: an SR free bet is much closer to a cash stake and needs little converting, though a book's terms can still limit how and when you withdraw it. The SNR bonus bet is the one this calculator is built for.
The Free Bet Conversion Formula
To balance the two bets, you want the same profit whether your free bet wins or your hedge wins. With a free bet of value F at decimal back odds O(b), hedged on the other side at decimal odds O(h), the hedge stake is:
Hedge stake = F × (O(b) − 1) ÷ O(h)
And the profit you lock in either way is:
Profit either way = F × (O(b) − 1) × (O(h) − 1) ÷ O(h)
You do not have to memorize this. The point is to see why the result moves: the longer your back odds O(b), the bigger that (O(b) − 1) term, and the more of the bonus you keep. It is the single most important lesson in this whole guide, and the next two sections show it in numbers.
A Worked Example: Converting A $100 Bonus Bet
Say you have a $100 SNR bonus bet and a two-way market (a tennis match works well, since there are only two outcomes). You decide to use the bonus on the underdog.
- Free Bet: the underdog at +400 (decimal 5.00) on DraftKings, using your $100 bonus bet.
- Hedge: the favorite at −455 (decimal ≈1.22) on FanDuel, with real cash.
Plug it into the formula: hedge stake = 100 × (5.00 − 1) ÷ 1.22 = $327.87 (rounding the hedge decimal to 1.22).
Now check both outcomes:
| Outcome | Free bet (underdog, +400) | Hedge (favorite, $327.87) | Your net profit |
|---|---|---|---|
| Underdog Wins | +$400 profit (stake not returned) | −$327.87 (hedge loses) | +$72.13 |
| Favorite Wins | $0 (bonus bet loses, cost you nothing) | +$72.13 profit | +$72.13 |
Either way you bank about $72 in withdrawable cash from a $100 bonus bet, a 72% conversion rate, and the result of the match no longer matters to you. That balance is the whole point.
Two honest notes. First, you had to put up $327.87 of your own money on the hedge, more than the face value of the bonus, and that cash is tied up until the match settles. Second, this is low-risk, not risk-free: if a price moves before you place the second leg, or a book voids or restricts the bonus, the balance can break. We will cover that below.
Skip the arithmetic. The moment you type your three numbers in, the tool surfaces the exact hedge stake, the profit you keep either way, and your conversion rate — so you never run the formula by hand or risk a rounding slip on the hedge. That is what the OddsShopper Free Bet Converter is for. New to OddsShopper? It is a suite of tools that scans every major US sportsbook and shows you the best price on every side of a market. You can try the full toolkit free for 7 days, and code FREEBET20 takes 20% off OS Pro or OS Core if you subscribe.
How The Conversion Rate Changes With The Odds
Most free bets quietly leak their value right here. The same $100 bonus converts to wildly different amounts depending on the odds you use it on. Burn it on a heavy favorite and you keep only about a third, because the free bet's profit (the only part you keep) is small. Use it on a longer-priced underdog and you keep far more.
The pattern below uses a roughly fair hedge price on the other side. Treat these as illustrative, since your real number depends on the exact hedge you can find:
| Free Bet Odds | Decimal | Approx. cash from a $100 bonus bet |
|---|---|---|
| −200 (Favorite) | 1.50 | $33 (33%) |
| +100 (Even) | 2.00 | $50 (50%) |
| +200 | 3.00 | $66 (66%) |
| +400 | 5.00 | $72-80 (72-80%) |
| +1000 | 11.0 | $80-90 |
The row I keep coming back to is the jump from −200 to +400: the same $100 bonus that converts to about $33 on a heavy favorite banks $72-80 on a +400 underdog — more than double the cash, from one promo, just by choosing the price. The takeaway is blunt: never use an SNR bonus bet on a short favorite if you are trying to convert it. The longer the odds, the more of the bonus you keep. The catch is that many promos set a minimum odds requirement (often around −200 or longer), so read the terms and aim for the longest eligible price you are comfortable hedging. To find the best price on each side, shop the line across books on the OddsShopper odds screen before you lock anything in. A better hedge price means a higher conversion rate, the same way line shopping adds free value to any bet.
How To Convert A Free Bet, Step By Step
- Confirm the bonus type and terms. Make sure it is an SNR bonus bet, and check the minimum odds, eligible markets, and expiry date.
- Find a two-way market (a moneyline, a total, a tennis or fight winner) where you can back both sides.
- Pick the longest eligible odds for the free bet side, then find the best available price on the opposite outcome at a second book.
- Run the numbers through the Free Bet Converter to get the exact hedge stake and your conversion rate.
- Place the free bet first, confirm it accepted, then place the cash hedge at the price you planned. Order matters, because the bonus is the leg you cannot easily replace.
- Wait for both to settle. Your profit is the same regardless of which side wins.
The Risks: Low-Risk, Not Risk-Free
Converting a bonus bet is one of the safest plays in betting, but "safe" is not "certain," and any calculator that promises a certainty is overselling it. It also helps to know what this is not: you are realizing the value of a promo, which is different from hedging a normal bet you would otherwise want to keep. Cashing out or hedging a wager that is already priced in your favor usually gives back the very edge you found, so save this play for bonus bets.
- Lines Move. If the hedge price drifts between your two bets, your two legs no longer balance. Place them close together, and pull the best available hedge price off a real-time multi-book scan the second before you confirm, so you are hedging at the sharpest number and not last night's line.
- Books Can Void Or Restrict. A sportsbook can settle a market differently than you expect, limit your account, or pull a bonus that breached its terms. The math only holds if both bets stand and settle normally.
- Your Cash Is Committed. The hedge ties up real money, often more than the bonus is worth, until the event ends.
- Terms Vary. Minimum odds, eligible sports, one-time use, and short expiry windows all shape how much you can realistically convert.
None of this makes conversion a bad idea. It is still the most reliable way to turn a promo into withdrawable cash. It just means you treat that profit as "very likely" rather than "promised," and you keep your bets within what you can afford. (Betting is for ages 21+ where legal.)
Frequently Asked Questions
What is a free bet conversion calculator? It is a tool that takes your bonus bet amount and two prices, then tells you the exact hedge stake to bet on the opposite side so you keep a similar profit either way, once both bets are placed at those prices. OddsShopper's Free Bet Converter does it instantly.
How much is a $100 free bet actually worth? Usually $60 to $80 in real cash, because most bonus bets are SNR (stake not returned), so you only keep the profit. The exact figure depends on the odds you use it on, which is why longer odds convert better.
What is a good free bet conversion rate? Anything in the 70-80% range is strong. You hit the higher end by using the bonus on longer odds and finding a tight hedge price on the other side. Short favorites can drop you below 30%.
Should I use my free bet on a favorite or an underdog? An underdog, almost always. The free bet only pays its profit, and longer odds mean a bigger profit, so a +400 bonus bet keeps far more value than a −200 one. Just respect the promo's minimum-odds rule.
Do I need a betting exchange to convert a free bet? No. You can hedge at a second sportsbook, which is how most U.S. bettors do it. An exchange can squeeze out a slightly higher conversion rate through lower fees, but it is not required.
Is converting a free bet the same as arbitrage? The hedging math is the same, but the source of the edge differs. Conversion banks the value of a promo; arbitrage banks a gap between two books' prices on a normal market. Both are about expected value over the long run.
Can I lose money converting a free bet? A correctly sized conversion produces a similar positive result on either side, but a loss is possible if the odds move between your two bets, a book voids or restricts a wager, the promo terms are breached, or the hedge is mis-sized. Running the math through the calculator and placing the free bet first is exactly how you keep those failure modes off the table. Treat the profit as very likely, not promised.
- Devig Calculator: Find Fair No-Vig Odds From -110 Prices
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- What Is A Free Bet? How Bonus Bets Actually Work
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- Free Sports Betting Picks: Where To Find And Vet Them
Get The Most Out Of Every Bonus Bet
A calculator turns a bonus bet into cash. The bigger edge is spending the free bet well in the first place: filter to a clean two-way market that will not get voided, take the longest eligible price you can find a tight hedge against, and check both numbers at the moment you place — not the moment you planned. That is the difference between an 80% conversion and a 50% one on the same promo.
OddsShopper is built for exactly that. It scans every major US sportsbook in real time, flags the bets priced in your favor with Portfolio EV, and the free Free Bet Converter handles the conversion math for you. Once the bonus is banked, our free expert picks today are a good place to point that fresh cash. Try the full toolkit free for 7 days, then code FREEBET20 takes 20% off your first payment on OS Pro or OS Core.
