Buying Power Calculator
From cash, margin multiplier and unrealised P/L, compute your available buying power for trading.
Input Data
Results
At a glance:Buying power is the maximum market value you can buy in a brokerage account. buying power = (cash + unrealised P/L) x margin multiplier. Example: cash 100k, 4x, no P/L → 400k; if you already hold 100k of margin stock, available = 400k - 100k = 300k. Margin amplifies gains AND losses; a margin call can force liquidation in a downturn. In Hong Kong, securities margin is subject to SFC and exchange rules (e.g. 50% initial margin for many positions); broker terms vary. Estimate only, not advice.
Formula
Buying power = nominal amount × (base CPI ÷ current CPI).
$$$PP = Amount \\times \\dfrac{CPI_{base}}{CPI_{current}}$$$$$$Amount$ $CPI_{base}$ $CPI_{current}$$$$$$1{,}000 \\times \\dfrac{100}{120} \\approx 833.33$$$How to Use
- Enter the cash balance and the margin multiplier.
- Enter any unrealised P/L on open positions.
- View the available buying power.
FAQ
What is buying power?
The maximum market value you could buy in the account with your cash and margin. With a 4x multiplier, HK$100,000 cash gives HK$400,000 of buying power. It shows spare capacity and the leverage you carry.
How does margin multiply risk?
Margin lets you control more than your cash; gains and losses are both magnified versus the cash put in. A small adverse move can blow up the loss ratio and trigger a margin call — the broker demands more cash or sells your holdings, possibly at the worst time. Use leverage with strict risk control.
What is a margin call?
When your equity falls below the maintenance requirement (after losses), the broker asks you to top up cash or close positions. If you cannot, it liquidates — often locking in losses. Keep a buffer and never run buying power to the limit.
Does Hong Kong regulate margin?
Yes. Hong Kong securities margin trading is supervised by the SFC and exchanges; many stock positions require a 50% initial margin (2x) and a maintenance level. Leveraged FX/commodity products may have stricter or different rules. Broker terms differ — read your agreement.
How does this relate to day-trading buying power?
Some markets allow intraday 4x for pattern day traders; the principle is the same (multiplier times cash), but it may only apply to positions closed same day. This tool uses the multiplier you enter; set it per your account and product rules.
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References
Content review: Calculatorism Finance Team. Results are for reference only; please refer to the relevant authorities for the official figures.