Stock Average Calculator

How to use

1. 1Pick the currency and add a label for the position you are tracking (ticker, fund name, anything you want).
2. 2For each purchase add a row with the share count, the price per share, and the broker fee or trading commission (leave fee blank if there was none).
3. 3Read the headline weighted average cost per share, plus total shares, total invested, total fees, and the break-even price.
4. 4Optional: enter today's market price to see your current value, unrealized profit or loss, and P/L percent. Gains show in green and losses in rose.
5. 5Optional: in the Average down section enter a new buy price and a target average to learn exactly how many more shares you need to buy. The result rounds up to whole shares so it is actionable.
6. 6Use Copy average to grab the headline number, Copy full report (CSV) to paste into a spreadsheet, or the per-row Copy buttons next to any line item.

About this tool

Stock Average Calculator finds the weighted average cost per share across any number of buy orders. Add a row for each buy with the share count, the price per share, and an optional broker fee or trading commission. The result panel reports your total shares, your total invested (with and without fees), the weighted average price per share, the break-even price (the price at which selling all shares returns the capital you put in), and an optional unrealized P/L block when you fill in today's market price. The average-down section solves the question retail investors actually search for: 'I already average X, the stock now trades at Y, how many more shares do I need to buy at Y to drop my average to a target Z?' The tool solves the algebra in one step and rounds the result up to whole shares so the answer is actionable at any broker. The same math works in reverse for averaging up to a target. Eight currencies are supported (USD, EUR, GBP, CAD, AUD, INR, JPY, TRY) and a no-symbol decimal mode lets you use it as a generic weighted price calculator. Fractional shares and decimal prices work for crypto positions across exchanges, fractional share brokerages, and any market that allows non-integer share counts. Quick-fill chips load common scenarios: a monthly dollar cost average plan, an average-down after a drawdown, a multi-exchange crypto position with fees, and a UK stock with a fixed broker commission. The lot table below the result panel shows each buy's contribution as a percent of the position, and a Copy CSV button drops the full report (lots and summary) into a spreadsheet. The calculator is purely a cost basis tool: it does not handle stock splits, dividend reinvestment, FIFO or LIFO tax lot accounting, currency conversion on foreign buys, or capital gains tax. Everything runs locally in your browser; no portfolio data is uploaded.

Free to use. Works in your browser. No signup, no login.