Available balance is the part of your equity that is still free after margin for open futures positions has been locked. For traders searching available balance, the key point is simple: it shows what is left to support new orders or cover changes in your account before you close a trade. In this guide, futures means USDT-margined perpetuals, and equity means your account value after open-position gains, losses, and funding are included. You can see those figures in the play-money portfolio and your funding entries in the play-money wallet. On ZK Futures, every balance is play money in test USDT, and a new account starts with 1,205.50 test USDT.
What available balance means in futures
In futures, equity is your account value after unrealized PnL is included. Margin is the collateral assigned to support a futures position. Those two ideas are the base for reading available balance correctly.
Available balance is not the same as your total balance. A futures account can show more equity than you can freely use, because some of that equity may already be tied up in open positions as margin. That is why traders usually read available balance as the portion of equity that is still free, not as the full account amount.
With isolated margin, each position has its own margin allocation. Isolated margin means only the margin assigned to that position is at risk of liquidation. In practice, opening one trade reduces what is left for other trades, but it does not pool all positions into one shared margin bucket.
That is also why available balance matters in the play-money terminal. It helps show how much room is left before a trader becomes overextended. Many interfaces also show used margin next to available balance, and those two numbers are easier to understand together than on their own.
A simple example makes the arithmetic clearer:
- equity: 1,205.50 USDT
- initial margin locked in one position: 100 USDT
- remaining equity before any unrealized PnL or funding effects: 1,105.50 USDT
That remaining amount is what the interface can show as available balance. If you are comparing markets, the play-money market list can help you see where the same account equity may be split across different perpetuals.
How leverage and initial margin change it
Leverage lets a trader control a position value larger than the margin posted for it. Position value is the notional size of the contract exposure in USDT. The key formula is simple: initial margin = position value / leverage.
When a position opens, that initial margin is locked from available balance. So if your equity stays the same but you choose a different leverage setting, the amount removed from available balance changes right away.
A basic example:
- position value: 1,000 USDT
- at 10x leverage, initial margin: 100 USDT
That means 100 USDT is locked to support the position, and available balance drops by that amount at entry.
Now compare the same 1,000 USDT position at other leverage levels:
- at 2x leverage, initial margin: 500 USDT
- at 10x leverage, initial margin: 100 USDT
- at 100x leverage, initial margin: 10 USDT
This is why higher leverage can make available balance look larger after entry: less margin is locked upfront. But the trade is not safer. The position value is still 1,000 USDT, so the market exposure has not shrunk; only the margin buffer has.
The arithmetic behind that buffer is worth remembering. With 10x leverage, a 10% adverse move uses up the initial margin. With 100x leverage, a 1% adverse move does. With 2x leverage, a 50% adverse move does. That is the same idea discussed in risk and reward: less posted margin does not mean less risk.
In other words, lower initial margin changes how much balance is free today, not how large the position really is. That is why leverage should be read together with liquidation risk, entry level, and cost basis in futures. It also helps explain why fast moves, including a short squeeze, can make a thin margin buffer disappear quickly.
Why unrealized PnL, mark price, and liquidation matter
Unrealized PnL is the open gain or loss on a position that has not been closed yet. It matters because available balance is tied to account equity, so it can change while the trade is still open.
That change is based on the mark price. Mark price is the reference price used to value an open futures position for margin checks. This is different from the latest trade price, which may jump around for a moment after a fast fill or a thin print. If you are used to spot trading, this is one of the main reasons futures balances can behave differently from what you might expect after a market order on spot.
The level that matters most after that is the liquidation price. Liquidation price is the mark price where a position no longer has enough equity to stay open under the maintenance rule.
In this setup:
- maintenance margin is 0.5% of the position value at the mark price
- liquidation happens when margin plus unrealized PnL falls to that level
- with isolated margin, the loss is capped at the position's margin
The formulas are:
- long liquidation price = entry price x (1 - 1/leverage) / (1 - 0.005)
- short liquidation price = entry price x (1 + 1/leverage) / (1 + 0.005)
So available balance can look fine while one position is still close to liquidation. That is why this figure should be read as spare room in the account, not as proof that an open trade is safe.
Related topics such as cash and carry pricing, what a carry trade means, a liquidity sweep, or counterparty risk in crypto answer different questions. Here, the key point is simpler: mark price decides unrealized PnL, and unrealized PnL helps decide how close a position is to liquidation.
How funding and execution affect your free margin
Funding is the recurring payment exchanged between long and short positions in a perpetual market to help keep the contract near the spot market. It is separate from price-based PnL, but it still changes equity, so it also changes free margin.
The direction is fixed by the funding rate:
- at a positive rate, longs pay shorts
- at a negative rate, shorts pay longs
In ZK Futures, funding is settled every 30 seconds in the demo. Many exchanges use 8-hour funding, and some use hourly funding. Each demo settlement is capped at 0.1% of the position value.
One example is enough. If the funding rate is 0.01% and the position value is 10,000 USDT, the payment for that settlement is 1 USDT. Paying funding lowers equity by 1 USDT. Receiving funding raises equity by 1 USDT. No price move is needed for either change.
Execution changes free margin in a different way. The order book is the queue of bids and asks waiting to trade at specific prices. In this setup, each market matches by price-time priority, which means the best price trades first and orders at the same price fill first in, first out.
That matters because your actual fill sets the entry price of the position. Entry price then affects the distance to liquidation from the moment the trade opens. A fill that lands less favorably can leave less room before the position reaches maintenance margin, even if the leverage setting is unchanged.
So free margin is shaped by two quiet mechanics traders often miss: funding transfers and the exact price where the order fills.
Reading available balance without fooling yourself
Available balance is a useful snapshot, but it is not the whole risk picture. On its own, it does not tell you how large your open positions are, how much exposure they carry, or how close they already are to liquidation.
A trader can still have a positive available balance and be in danger. If a highly leveraged position is already near its liquidation price, that remaining free balance can give a false sense of safety.
The number can also change fast because several parts move at once:
- opening another position locks more margin
- a favorable or adverse mark-price move changes unrealized PnL
- funding payments raise or reduce equity
That is why it helps to think in terms of buffers, not maximum size. Leaving room for volatility is different from using every bit of free margin the moment it appears.
Set risk limits in a way that fits your own situation and keep leverage and liquidation risk in view at the same time. If you want the next step for position sizing and downside awareness, read risk and reward.
Common questions about available balance
Is available balance the same as buying power?
Not exactly. Available balance is the equity not locked as isolated margin for open positions. Buying power is how much position value that free amount can support once leverage is applied.
Because of that, the two numbers can move differently. A smaller available balance can still support a larger position value if leverage is higher, but the margin buffer is thinner and liquidation can come sooner.
Why can available balance fall even if the market barely moves?
Small changes can add up in futures. Available balance may drop because:
- a pending or newly filled order locks initial margin
- funding is settled between longs and shorts
- mark price moves slightly against an open position
- part of the balance is tied to another isolated position
So the number can change without any position being closed.
If I use isolated margin, does available balance protect an open trade?
No. Isolated margin separates one position’s risk from the rest of the account. That means the loss on that position is capped at the margin assigned to it, but the position can still be liquidated when its equity reaches maintenance margin.
Available balance sits outside that position until you use it for something else. It does not automatically become margin for the trade.
How can I read available balance in a safer way?
Treat it as spare room, not as a signal to use maximum size. Check it together with:
- position value
- leverage
- unrealized PnL
- liquidation price
- upcoming funding settlements
On ZK Futures, these figures are shown with play money only. Every balance is play money in test USDT, and a new account starts with 1,205.50 test USDT.
Conclusion
For futures traders, available balance is best read as what stays flexible in the account while isolated positions stand on their own margin. It helps answer practical questions such as whether there is room for another order, how much of equity is already committed, and whether recent funding or mark-price changes have tightened the account.
Keep this number in context:
- free balance can shrink without a trade being closed
- a position can still be near liquidation while available balance remains positive
- in ZK Futures, every balance is play money in test USDT, and a new account starts with 1,205.50 test USDT