The available advancebet amount can be viewed on your bet slip. Click on the "find out" button opposite "available advancebet" and you will see the funds available as an advancebet.

On which types of event can I use my advancebet?
Advance bets can only be placed either on Live sports events or on sports events that are due to start within 48 hours.

Terms of Advancebets:
Additional Advancebets can be placed even if you already have unsettled Advancebets.
1xBit reserves the right to offer or cancel this bonus at the discretion of the company without stating a reason.
Advancebets are offered based on an evaluation of the potential returns from your unsettled bets.
All bets placed before Advancebets and settled within 48 hours after placing of Advancebets will be used to cover the Advancebets made.
If, after settlement of the bets made before Advancebets, the returns do not cover the amount of the Advancebets used, the Advancebets are deemed void.
Deposits made after using an Advancebet cannot be used for covering the Advancebets.
Example
Your account balance is mBTC260. You have made the following bets:

mBTC100 at odds of 1.5 – potential returns are mBTC150.
mBTC150 at odds of 2 – potential returns are mBTC300.
Now your available balance is mBTC10.

We offer you an Advancebet of mBTC100. Now you are able to place bets with a combined stake of up to mBTC110.

You place a bet with a stake of mBTC30 (mBTC10 of your available balance and mBTC20 of the Advancebet amount) at odds of 1.5. Potential returns are mBTC45.

You also place a bet with a stake of mBTC50 (from your Advancebet balance) at odds of 2. Potential returns are mBTC100.

Let's consider 3 possible outcomes:
Bets made using the Advancebet amount have won. Expected payouts are mBTC45 and mBTC100. Bets made using own account balance have lost. Bets using the Advancebet amount will be deemed void. Your own funds of mBTC10 that were part of your Advancebet stake will be refunded to your account.
Bets made using the Advancebet amount have lost. Bets using own account balance have won. The payout is (150+300)=mBTC450. mBTC50 and mBTC20 was used as Advancebets (plus mBTC10 of your own funds). The amount of the Advancebets made will be deducted from the payout (150+300)-50-20 =mBTC380. So, mBTC380 will be credited to your account.
Bets made using the Advancebet amount have lost. Bets made using own funds have lost. In this case, bets made as Advancebets will be deemed void. mBTC10 of your own funds used as part of your Advancebet stake is deemed to be lost.