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Kelly Criterion Calculator

Compute the optimal fraction of your bankroll to stake from your win probability and win/loss ratio, with half and quarter Kelly.

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Kelly Criterion Calculator is free to use as often as you like, directly from this page. You will find it under Investing & markets, with Capital Gains Yield Calculator and Dividend Payout Ratio Calculator for the neighbouring cases.

How to use it

  1. Open the tool — no signup or install needed.
  2. Enter your input or adjust the available options.
  3. Get your result instantly, then copy or download it.

Frequently asked questions

What is Kelly Criterion Calculator?

Compute the optimal fraction of your bankroll to stake from your win probability and win/loss ratio, with half and quarter Kelly.

When would I actually use this?

Comparing two investments that pay at different times, deciding whether a project clears its cost of capital, and sanity-checking a valuation someone else produced.

What is the most common mistake?

Trusting a valuation without asking what share of it comes from the terminal value. Past 70%, the answer is an assumption about the distant future dressed up as a calculation.

How is Kelly Criterion Calculator different from Capital Gains Yield Calculator?

They sit next to each other but answer different questions: Capital Gains Yield Calculator is the one to open when you need it to compute the capital gains yield from the purchase and current price, with dividend yield, total return and the annualised equivalent. Pick whichever matches what you're starting from — both are free.

Is there a tool for the next step?

Dividend Payout Ratio Calculator is the closest one after this: Two ways in — total dividends over net income, or DPS over EPS — with the retention ratio as its complement and what each level implies.

What else is worth having open alongside it?

Dividend Reinvestment (DRIP) Calculator and Effective Yield Calculator — they come up in the same task often enough to be worth a second tab.

Where do the figures come from?

Discounting, IRR and payback are defined identically everywhere, so the arithmetic is not in dispute — the assumptions you feed it are. Change the discount rate by a point and re-read the answer.

Further reading

All guides →
ExplainerRisk/Reward Ratio Explained: The Win Rate Each Ratio RequiresA 1:3 ratio does not make you right more often — it lets you be wrong three times out of four and still break even. Here is the inversion, a table of ratio against required win rate, and what costs do to both.GuidePosition Sizing: What the 1 Percent Rule Actually ConstrainsThe rule caps the loss, not the position. Here is the formula, a worked example, and what a run of ten losses costs at 1 percent versus 2 percent.ExplainerPrice Return, Total Return and Yield Are Three Different NumbersThe index quoted in the news is almost always a price index. At 5 percent price growth and a 2.5 percent reinvested yield, 30 years turn $10,000 into $43,219 on price and $90,656 on total return — the price measure misses 58.8 percent of the gain.ExplainerDividend Reinvestment: What Actually Drives the DifferenceReinvesting a 3 percent yield for 30 years turns 100 shares into 242.7 and multiplies the final position by exactly that factor: $32,434 becomes $78,726. Tax at 30 percent on each dividend costs $18,223 of it — nearly two and a half times the tax actually paid.ExplainerTax-Equivalent Yield: Comparing a Tax-Free Bond With a Taxable OneTaxable-equivalent yield = tax-free yield ÷ (1 − marginal rate). A 3.00 percent tax-free yield is worth 3.85 percent at a 22 percent marginal rate and 5.07 percent at 40.8 percent. The trap is that it is the marginal rate, surtaxes and social levies included — leaving them out costs 0.85 points of yield.ExplainerPaying Off a Loan Early: What Actually ChangesAn overpayment earns exactly the loan's rate, risk-free and after tax. On $200,000 at 5.00 percent over 25 years, $20,000 paid at the start saves $42,092 of interest; the same sum at year 16 saves $11,088; applied to the payment instead of the term it saves only $15,075.