“Free bet” is not a single calculation type. The most important detail is whether the promotional stake is returned with the winnings. That one rule changes the value of the back bet and the stake you need to lay at the exchange.
Stake returned and stake not returned
With a stake-returned free bet, the original promotional stake is included in the bookmaker's return if the selection wins. With a stake-not-returned free bet, you receive the winnings but not the promotional stake itself. The difference is reflected in the calculator mode and in the expected result.
Do not infer the rule from the promotion's headline. Read the current terms and check whether the rule applies to the whole reward, to a particular product, or only after additional wagering.
Check the free-bet conditions first
- Whether the free bet is stake returned or stake not returned.
- The expiry date and whether the bet must be placed or settled by then.
- Minimum odds, eligible markets and whether singles are required.
- Whether the reward can be split or must be used in one bet.
- Any maximum winnings, commission, cash-out or withdrawal restrictions.
A reward can also have a separate qualifying condition before it becomes usable. Keep the qualifying bet and the free-bet conversion as separate records in your tracker.
Plan the conversion, then sanity-check it
Enter the free-bet value, back odds, lay odds and exchange commission in the correct mode. The calculator should show the back stake, lay stake, liability and expected result. Check that the lay liability is affordable and that the exchange has enough money and liquidity.
Compare both settlement outcomes before placing the bet. If the figures look unexpectedly positive, unusually negative or different from the promotion's rule, stop and check the mode and inputs. A free-bet calculation that uses the wrong stake rule can be wrong while still looking plausible.
Record the reward through settlement
Save the planned bet and note the free-bet expiry. When it settles, record the bookmaker result, exchange result, commission and any withdrawal or balance movement. The reconciliation guide covers the final check.
If the terminology is still unfamiliar, use the matched betting glossary alongside the calculator rather than relying on an old example.