Know Exactly How Much to Invest in Any Stock
This free calculator gives you a volatility-adjusted position size in 10 seconds — so you never risk too much on a single trade.
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3 Simple Steps
How It Works
Get your personalised position sizes in under a minute.
Enter Your Details
Pop in your portfolio size, risk tolerance, and the ticker you're looking at. Takes 30 seconds.
Get Your Numbers
The calculator analyses real volatility data and returns a position size tailored to your risk level.
Invest Smarter
Use your results to size every position properly — no more guessing, no more concentrated bets.
The Problem
Why "Equal Allocation" Is a Myth
Putting 10% of your portfolio into Apple, 10% into Nvidia, 10% into Tesla, and so on might feel balanced.
It isn't.
Nvidia moves nearly twice as much as Apple on any given day. Same percentage allocation, completely different risk exposure. Your "balanced" portfolio is actually a concentrated bet on your most volatile holdings.
The Cost of Guessing
Every time you pick a position size without accounting for volatility, you're either risking too much (and losing sleep) or risking too little (and missing returns). This calculator removes the guesswork.
What's Inside
Everything You Need to Size Positions Properly
Single Stock Calculator
Enter any US ticker — get a position size based on its actual volatility, not guesswork.
Full Portfolio Mode
Balance your entire portfolio in one go — see how all your positions stack up against each other.
Risk Tolerance Settings
Conservative, balanced, or aggressive — adjust recommendations to match your comfort level.
Plain English Explanations
No jargon. Every number comes with a clear explanation of why — so you actually learn.
How It Works
Three Steps. Ten Seconds.
Enter your email
Get instant access — no waiting, no sales calls, no nonsense.
Type in a ticker
Works with any US stock — AAPL, NVDA, TSLA, whatever you're considering.
Get your number
A volatility-adjusted position size with a clear explanation of why.
FINK translates the markets into simple, actionable insights. The position sizing approach alone changed how I think about risk — I finally sleep at night knowing my portfolio is properly balanced.
Built by FINK
Who's Behind This?
David Belle
15+ years in financial markets, teaching retail investors how to approach investing systematically. This calculator uses the same volatility-adjustment principles taught in the FINK Academy — now available free.
Ready to Size Your Next Position?
Get the calculator free. Takes 10 seconds to access.