Position Size Calculator

Size every trade by a model, not a guess — equity and futures (with margin). Built on Van Tharp's position-sizing framework: pick a model, learn how it works, and apply it.

Learn: What is Position Sizing? →

Percent Risk

Risk a fixed % of your account on every trade.

Account equity
Risk per trade
Entry price
Stop-loss price

Your position

Position size200 shares
Capital at risk
₹1,000
Risk of equity
1%
Position value
₹20,000
Save your risk profile & auto-size every trade

How the Percent Risk model works

You decide the most you are willing to lose on one trade as a percentage of your account — commonly 0.5–2%. Position size is that rupee amount divided by your per-unit risk (the distance from entry to stop). Because size scales with the stop distance, a tight stop lets you hold more units and a wide stop fewer, so every trade risks the same fraction of capital. For futures, per-unit risk is multiplied by the lot size, and the result is capped by the margin your equity can cover.

When to use it

The default for most discretionary traders. Use it whenever you have a defined entry and stop-loss.

Framework popularised by Dr. Van K. Tharp; explanation written by Tracktions. Further reading.

Formula

Position Size = (Account × Risk %) ÷ (Entry − Stop Loss)

Worked Examples

Equity trade at 1% risk

Inputs

Account Size
₹1,00,000
Risk per Trade
1%
Entry Price
₹250
Stop-Loss Price
₹245

Outputs

Risk per Share
₹5
Position Size
200 shares
Capital at Risk
₹1,000
Position Value
₹50,000

You risk ₹1,000 (1% of ₹1,00,000). With a ₹5 gap between entry and stop, you can buy 200 shares before that loss is reached.

Tighter stop — same risk budget

Inputs

Account Size
₹1,00,000
Risk per Trade
1%
Entry Price
₹250
Stop-Loss Price
₹248

Outputs

Risk per Share
₹2
Position Size
500 shares
Capital at Risk
₹1,000
Position Value
₹1,25,000

A tighter stop forces a larger position to hit the same ₹1,000 risk budget — illustrating why stop placement drives position size, not the other way around.

Common Mistakes

  • Setting position size before defining the stop-loss.
  • Risking more than 1–2% per trade early in a system's lifecycle.
  • Ignoring brokerage and slippage, which erode the true risk amount.
  • Treating capital allocation (how much you buy) as the same as capital at risk (how much you can lose).
  • Using a mental stop instead of a hard stop when calculating size — the math only holds if the stop is honoured.

Frequently Asked Questions

What percentage should I risk per trade? +

Most systematic traders risk 0.5–2% per trade. Beginners are advised to start at 0.5–1% until they have at least 50 trades of live performance data. Risking more amplifies both wins and losses in ways that make it harder to distinguish skill from luck.

Can I use this calculator for options? +

Yes — treat the option premium as your effective stop-loss distance. Enter the premium you are willing to lose as the risk amount and set the entry price to the underlying's price. Note that options have non-linear risk profiles and this calculator assumes a fixed worst-case loss.

Does it work for futures? +

Yes — switch to the Percent Risk (Futures) model. The calculator accounts for lot size, tick value, and margin so that the displayed position size is in contracts rather than shares.

What if my stop changes after I enter? +

Recalculate position size any time you move your stop. Widening a stop mid-trade without reducing size increases your actual risk beyond your plan. It is safer to set the stop at entry and not adjust it wider.

What is the connection to Van Tharp? +

Van Tharp popularised percent-risk position sizing in "Trade Your Way to Financial Freedom". He showed that controlling the dollar amount risked per trade — rather than picking entry signals — is the primary driver of long-term equity curve shape.

Do this automatically in Tracktions

Auto-size trades in Tracktions Risk Console

Educational tool only. Tracktions is a trade-journaling and analytics tool, not investment advice — we are not SEBI-registered advisers and do not provide trade recommendations or assurances of returns. Every result is based solely on the numbers you enter; confirm lot sizes and margins with your broker before trading.