The two hedges
With an original stake S at odds O, and the other side now at odds H:
same result either way: h = S × O / H
cover the original stake: h = S / (H - 1)
When it works and when it doesn't
A hedge only fixes a positive result if the price on the other side has lengthened enough relative to yours. If it hasn't, the same formula fixes a small loss instead. The calculator shows both results so you can see which one you are buying.
Placing both sides at once, at prices whose implied probabilities already add up to less than 1 across two books, is a surebet. The surebet calculator splits that stake.
Things to check
The hedge has to be the exact opposite of the original bet under the same rules: same market, same period, same line, same treatment of extra time or retirements. A hedge on a slightly different market can lose alongside the original.

