Stock calculators
Six calculators for the sums that come up when you read a quote page or plan a trade. Each one prints the working line by line, so you can check it and see which input moves the answer most.
- P/E Ratio Calculator
Price and earnings per share in, P/E and earnings yield out, trailing or forward.
Background: P/E ratio
- PEG Ratio Calculator
Divide a P/E by the expected growth rate, and see how sensitive the answer is to that rate.
Background: PEG ratio
- DCF Fair Value Calculator
A two-stage discounted cash flow model with every assumption on the screen.
Background: the DCF walkthrough
- Dividend Yield Calculator
Current yield, yield on cost and the payout ratio against earnings and free cash flow.
Background: dividend yield
- Position Size Calculator
Shares to buy from your account size, the risk you accept and the distance to your stop.
Background: average true range
- CAGR Calculator
Compound annual growth rate between two values, for revenue, earnings or a share price.
Background: portfolio returns
Before you trust an output
Every calculator here runs in your browser and sends nothing anywhere. The answers are only as good as the inputs, and the inputs that matter most are the ones you have to estimate: a growth rate, a discount rate, where your stop goes. A calculator will happily turn a guess into a number with two decimal places.
Which one to open depends on the question. Valuing a company against its earnings is the P/E and PEG pair; valuing the cash it will produce is the DCF. Deciding how many shares to buy is the position size calculator, and it should come before the order, never after. Checking whether an income stock can afford its dividend is the dividend calculator, and comparing growth rates across companies or years is the CAGR calculator.
Change one input at a time and watch the output. If a small change in the growth rate doubles a fair value, the model is telling you how little it knows. That is worth knowing before you act on it.