Bid-ask spread calculator
This bid-ask spread calculator shows what the gap between bid and ask costs you. With a bid of 99.90 and an ask of 100.10 the spread is 0.20, or 0.2% of the mid price. Buy 50 units and sell at once and you lose 10 plus fees; the result appears instantly, with the steps.
Example: Bid price 99.9 · Ask price 100.1 · Number of units 50 · Fee per order 1 → Result: Spread 0.20 · 0.2 % of the mid price. Source: Wikipedia – Bid-ask spread. Updated: .
How it is calculated
The spread is the difference between the ask price and the bid price. You buy at the ask and sell at the bid. Anyone who buys a security and sells it again at once therefore pays at least the spread.
The formulas
- Spread: ask − bid
- Mid price: (ask + bid) ÷ 2
- Spread in percent: spread ÷ mid price × 100
- Round-trip cost: spread × units + 2 × fee per order
- Break-even: cost ÷ (ask × units) × 100: the percentage the price must rise for buying and selling to be cost-neutral.
What influences the spread?
Large, heavily traded assets usually have very tight spreads, rarely traded or volatile ones wide spreads. Outside trading hours and in sharp price moves the spread often widens. With a limit order you set the price yourself and avoid being filled at a poor price.
The calculator accepts any currency and treats the fee as a fixed amount per order. Percentage fees, taxes and other costs are not included.
Frequently asked questions
What is the bid-ask spread?
The difference between the highest price buyers are willing to pay (bid) and the lowest price sellers ask (ask). It is a cost of every trade.
How do I calculate the spread in percent?
Spread divided by the mid price times 100. With a bid of 99.90 and an ask of 100.10 that is 0.20 ÷ 100 × 100 = 0.2%.
What does it cost to buy and sell again at once?
Spread times units plus twice the fee. For 50 units, a spread of 0.20 and a fee of 1 per order that is 12.
What does break-even mean here?
The price rise in percent the security needs after buying at the ask so that selling at the bid including fees is possible without a loss.
How can I reduce the cost of the spread?
Trade liquid assets during main trading hours and use limit orders. Check bid and ask before you order.
Sources and legal basis
As of: · Editorial policy
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