Crypto position size calculator: risk, stop and lot step

Quote currencyA label only; nothing is converted

Account balanceThe amount available for this trade

Risk per trade (%)Your own figure; the calculator does not suggest one

Fee rate (%)Charged on the buy and again on the sell

Entry priceThe planned buy price

Stop priceBelow the entry; this calculator covers spot buys only

Target priceOptional; for the risk/reward ratio

Lot stepThe smallest quantity increment your platform allows; 8 decimals if empty

Position quantity—

Position value—

Position as a share of the balance—

Amount at risk—

Risk per unit (fees included)—

Loss at the stop (fees included)—

Balance cap—

Risk/reward ratio—

Net profit at the target (after fees)—

All default values are hypothetical, and the calculator suggests no risk percentage. It covers spot buys without leverage and assumes the stop fills at its price, which may not happen; the real loss can be larger.

Position size formula for crypto

Position size is the amount you are willing to lose at the stop, divided by what one unit loses at the stop once fees are counted. The calculator applies:

Risk amount = balance × risk per trade ÷ 100

Risk per unit = (entry − stop) + (entry + stop) × fee rate ÷ 100

Quantity = risk amount ÷ risk per unit, rounded down to the lot step

Position value = quantity × entry

Risk/reward = (target − entry) ÷ (entry − stop)

The fee term counts the buy and the sell, because a trade stopped out pays both. Without leverage the position cannot cost more than the balance, so the quantity is also limited to balance ÷ (entry × (1 + fee rate ÷ 100)), and the "Balance cap" row says when this applied.

Worked example

The balance cap shows up with a tight stop. With a balance of 1,000, 5% risk, entry at 1,500 and a stop at 1,490, at the same fee and lot step, the risk amount alone would allow about 3.849 units, but the balance pays for 0.666, so the quantity stops there and the loss at the stop is 8.65 USDT rather than 50.

Why a stop may not fill at its price

The result assumes the stop fills exactly at the stop price, which no order type promises. FINRA notes that a stop order becomes a market order once the stop price is reached, and in a fast market a sell can fill well below that level.

In the example, a fill at 1,350 instead of 1,425 costs 150 + (1,500 + 1,350) × 0.1% = 152.85 per unit, or 196.11 USDT on 1.283 units. That is nearly twice the planned 100 USDT. A stop-limit order avoids a fill below its limit, but FINRA warns there is no guarantee it executes, and then the position stays open.

Crypto trades around the clock, and thin order books can move far between two prices. This page covers the arithmetic of sizing and takes no view on where a stop or a target should go.

Lot step and minimum order size

The lot step is the smallest quantity increment a market allows, and rounding down to it keeps the loss within the risk amount.

Binance's spot API documentation, for example, states a LOT_SIZE filter with a minimum quantity, a maximum quantity and a step size, and a NOTIONAL filter that sets limits on price × quantity. Values differ by market and change over time, so read them from your own platform. If the step field is empty, the calculator rounds down to 8 decimals.

If the result is 0, the risk amount or the balance does not cover one step, and a hint under the step field says which. If the quantity is positive but below the platform's minimum order value, the order would be rejected, a check this calculator does not make. The same sizing matters in software that places orders: see trading bot risk management.

Spot only: no short side and no leverage

The calculator accepts only a stop below the entry and a target above it, so it covers a spot buy, without leverage or short selling.

Futures and margin positions need a liquidation check as well, because liquidation can come before the stop; the liquidation price calculator estimates that level and carries its own warnings. For readers in Turkey, Article 14 of Communiqué III-35/B.2 of the Capital Markets Board (SPK, also CMB) bars leveraged and short trading in crypto assets listed on platforms, and Article 99/A of Law No. 6362 treats foreign platforms' activity aimed at Turkish residents as unlicensed.

Fees and slippage also matter across many trades; compare them with the crypto trading fee calculator.

Which values to enter

• Balance: the amount available for this trade, in the quote currency. The currency field only changes the label.
• Risk per trade: your own figure, from above 0 to 100.
• Entry, stop and target: your planned prices. The target is optional and is used only for the risk/reward ratio and the profit row.
• Fee rate: the taker rate is the safer input for a stop that fills as a market order.
• Lot step: from your market's rules, for example 0.001.

Frequently asked questions

How do I calculate position size in crypto?

Divide the amount you accept losing at the stop by the distance between entry and stop plus fees, then round down to the lot step. With 100 at risk and 77.925 risk per unit, the quantity is 1.283 at a step of 0.001.

What percentage should I risk per trade?

This page does not suggest one. The 1% default is only an example, and the choice depends on your own rules and on how much you can afford to lose.

How do I work out the risk/reward ratio?

Divide the distance from entry to target by the distance from entry to stop. With entry at 1,500, stop at 1,425 and target at 1,650, that is 150 ÷ 75, shown as 1:2. The ratio says nothing about which level the price reaches first.

Why can my loss be larger than the risk amount?

A triggered stop usually becomes a market order, and in a fast market it can fill well below the stop price. The calculation assumes a fill at the stop.

Does this calculator work with leverage or futures?

No. It covers spot buys, and the quantity is capped by your balance. Leveraged positions also need a liquidation estimate, which is on a separate page.

Sources

• FINRA: Stop orders, factors to consider during volatile markets (26 March 2025) (opens in a new tab)
• FINRA: Order types (market and limit orders) (opens in a new tab)
• Binance Spot API documentation: Filters (LOT_SIZE, NOTIONAL) (opens in a new tab)
• Resmî Gazete: SPK Communiqué III-35/B.2, 13 March 2025, no. 32840, Article 14 (Turkish) (opens in a new tab)
• Capital Markets Law No. 6362, consolidated text, Article 99/A (Turkish) (opens in a new tab)

This calculator is general information, not tax, legal or investment advice. Results depend on the values you enter; fees, margin rules and tax rules differ by exchange and country and change over time, so check the official source and ask a licensed adviser about your own situation. Sources, checks and corrections: see the editorial policy.