Free Stock Average Calculator

How it works

Bought the same stock at different prices? Add each purchase — shares and price per share — and this calculator works out your total shares, total invested and your true average cost per share. Add today’s price to instantly see your profit or loss.

How the math works

Your average cost is a weighted average — bigger purchases count more than smaller ones:

Average cost per share = Total amount invested / Total shares

Each purchase contributes shares × price to the total invested. Buying 10 shares at $100 and 20 shares at $150 is not an average of $125 — it is ($1,000 + $3,000) / 30 shares = $133.33, because twice as much money went in at the higher price. Profit or loss at any current price is simply (current price − average cost) × total shares.

Everyday uses

• Averaging down: see how a dip purchase pulls your average cost toward your break-even point.
• Break-even checks: your average cost is exactly the price where profit and loss are both zero.
• Brokerage cross-check: verify the cost basis your broker shows, especially after several partial buys.

Frequently asked questions

Does this include brokerage commissions and fees?

Not by default. If your broker charges a per-trade fee, add it to that purchase by slightly increasing the price per share (fee divided by shares), or add the fee to the total for that row’s price. Most US brokers are commission-free for stocks, so the plain average is usually exact.

Should I average down on a falling stock?

This calculator only does the math — averaging down lowers your break-even but also concentrates more money in one position. Whether that is wise depends on why the price fell, not on the average itself.

Can I use this for crypto or mutual funds too?

Yes — the weighted-average math is identical for any asset bought in lots. Enter each buy’s units and unit price, whether they are shares, coins or fund units.