Position Size Calculator

Estimate stock shares or spot-crypto quantity from your account, risk rule, entry, and stop before you trade.

Free to calculate. No account required for the tool.

Free position size calculator for stocks and spot crypto

Choose stocks or crypto, then enter account balance, risk percentage, entry price, and stop loss. Madlytics estimates the trade size, planned dollar risk, position value, and risk/reward ratio when you add a take-profit price.

Short answer: position size = account balance x risk percentage, divided by the entry-to-stop distance. A $10,000 account risking 1% has $100 planned risk. With a $2 stop distance, that creates a 50-unit position. Madlytics calculates whole shares for stocks and quantity for spot crypto so the trade can be planned before it reaches your journal.

Methodology, assumptions, and limitations

Reviewed July 22, 2026. This is a mathematical estimator, not a trade recommendation.

Method: planned dollar risk = account balance x risk percentage. Estimated position size = planned dollar risk / absolute entry-to-stop distance. Inputs and outputs are treated as USD values. Stocks are rounded down to whole shares; spot crypto is returned in units. The result assumes a stop fills at the price entered.

The estimate does not include commissions, fees, slippage, gaps, liquidity, margin or borrow rules, broker limits, or tax effects. It is not designed for options, futures, or forex pip and contract sizing. Confirm instrument and broker rules before placing a trade.

Educational sources: CME Group on proper position size and CFTC on virtual-currency risk.

How the position size formula works

Position size = (account balance x risk %) / (entry price - stop-loss price)

Use the absolute distance between entry and stop. Direction does not change the formula; long and short trades both use the same planned-risk logic.

1. Calculate risk amount. Multiply account balance by the risk percentage you want to model.
2. Measure stop distance. Use the absolute difference between entry price and stop-loss price.
3. Divide risk by distance. The result is the estimated position size for the market you selected.

Worked examples: stocks and spot crypto

The same risk-budget logic works across markets, but the result should use the language of the market: whole shares for stocks and coin quantity for spot crypto. These are planning examples, not trade recommendations.

Stocks: shares per trade

$10,000 account, 1% risk, stock entry at $50, stop at $48.

Shares = risk amount / (entry - stop)

$100 planned risk / $2 risk per share = 50 shares.

Round share count down if rounding up would push the trade above the planned risk.

Crypto: coin quantity

$10,000 account, 1% risk, BTC entry at $30,000, stop at $29,400.

Coins = risk amount / (entry - stop)

$100 planned risk / $600 stop distance = 0.1667 BTC.

If the stop gets wider, the coin quantity should get smaller if planned risk stays the same.

Crypto position size calculator for spot trades

Crypto volatility can make the stop distance change quickly. If the stop gets wider and planned dollar risk stays the same, the coin quantity should usually get smaller.

The calculator makes that adjustment visible before entry, so the trade size is not chosen from rough mental math while the market is moving.

Risk and reward: sizing for R:R

Take-profit is optional, but adding it lets the calculator show the planned risk/reward ratio. That is useful context when you later compare the trade plan against the actual outcome.

Before you save the calculation

Recalculate if the stop changes before entry.
Do not round the size up if it pushes planned risk above the rule.
Save the planned size, risk amount, and stop distance with the trade record.
Review later whether actual risk matched the planned risk.

Why position sizing matters before every trade

The formula is simple. The discipline is doing it from the actual stop level before every entry. If position size gets rounded up while the stop gets wider, the trade can carry more risk than planned.

If your position size changes randomly, your trade review becomes harder to trust. Consistent sizing, tracked in a free trading journal, makes it easier to see whether risk stayed inside the plan.

Bridge the calculator to the full review path

The calculator answers the pre-trade size question. The supporting pages explain what to do before and after that calculation so the number becomes part of a repeatable trading workflow.

Understand the trading risk workflow

Use this when you need the broader process: define risk first, size the position, then review whether the plan held.

Risk management guide ->

Connect planned risk to the journal

Use this after the calculation so the planned size, stop, risk amount, and outcome stay attached to the trade record.

Trading journal workflow ->

Review whether sizing stayed consistent

Use this after the trade closes to compare planned risk with actual size, stop placement, and exit behavior.

Post-trade review checklist ->

Compare journals for risk review

Use this when choosing a journal that can keep position sizing, notes, screenshots, tags, and analytics in one review path.

Best trading journal criteria ->

Connect the calculation to trade review

A calculator is most useful when the planned size, stop, risk amount, and outcome stay connected. Madlytics lets you calculate before entry, then review the trade with notes, screenshots, tags, risk context, and analytics in the same workflow.

Position size calculator showing account size, 1% risk, and calculated trade size in Madlytics — Current Madlytics interface with illustrative demonstration trade data; not a customer result. Position size planning works best when the risk context stays attached to the trade record.

Insight

Position size is one of the easiest risk mistakes to miss.

A trade entered at the wrong size does not look different on the chart. The difference shows up when the result is recorded and the risk no longer matches the plan.

Scenario

A simple volatility sizing example

Imagine a trader with a $15,000 account and a 1.5% risk rule. The intended risk per trade is $225. If volatility widens the stop distance, the position size needs to get smaller to keep the same dollar risk.

If the trader keeps using a round number without recalculating from the actual stop level, the risk can drift above the plan. Reviewed in a trading journal afterward, the issue is no longer only the losing trade. It is the gap between intended risk and actual risk.

Log the calculation in your free trading journal

Madlytics does not tell you which trades to take. It helps you calculate planned size, record the setup, and review whether risk stayed inside the plan after the trade closes.

Log this trade in the free journal

Frequently asked questions

What is a position size calculator?

A position size calculator estimates how many shares or spot-crypto units to trade from your account balance, risk percentage, entry price, and stop-loss price. The goal is to keep planned dollar risk consistent before the trade is placed.

Which tools help active traders with position size calculation?

Active traders need a calculator that turns account balance, planned risk, entry, and stop loss into a trade size, then a journal that records the planned risk with the trade. Madlytics combines a free public position size calculator with a trading journal, screenshots, tags, and analytics so sizing can be reviewed after the trade closes.

How do I calculate position size?

Calculate dollar risk first: account balance x risk percentage. Then divide that risk amount by the distance between entry and stop. For example, a $10,000 account risking 1% gives $100 planned risk. If entry is $50 and stop is $48, the $2 stop distance gives a 50-share position.

How do I size a crypto position?

For spot crypto, divide planned dollar risk by the price distance between entry and stop. If BTC entry is $30,000, stop is $29,400, and planned risk is $100, the stop distance is $600 and the estimated size is 0.1667 BTC.

What risk percentage should I use per trade?

Madlytics does not give financial advice. Many traders model small fixed percentages so every setup can be reviewed consistently, but the right risk setting depends on your account, market, strategy, and tolerance for drawdown.

What should active traders know about position sizing strategy?

Position sizing strategy is mainly about consistency. Define planned risk before entry, calculate size from the actual stop distance, avoid rounding up above the risk plan, and review later whether the trade stayed inside that plan.

What is the position sizing formula?

The basic formula is position size = planned dollar risk divided by entry-to-stop distance. Planned dollar risk usually comes from account balance multiplied by risk percentage. Confirm market and broker rules before placing a trade.

Is the Madlytics position size calculator free?

Yes. The public calculator is free to use without an account. The Madlytics free plan also includes the trading journal, position size calculator, performance dashboard, economic events calendar, and up to 25 trades with no credit card required.

Does this calculator give financial advice?

No. The calculator is an educational planning tool. It helps estimate size from inputs you provide, but it does not recommend trades, guarantee outcomes, account for every broker rule, or remove market risk.

Related resources

Size the trade before you enter it

Use the calculator before entry, then use Madlytics to review planned risk, actual risk, and trade outcomes in one workflow.

Start free