Find your average cost per share after buying at two prices — the math behind averaging down (or up).
Average cost = total invested ÷ total shares. Averaging down lowers your break-even but adds money to a losing position — only sound if your thesis still holds. Excludes commissions and taxes. Not investment advice.
When you buy the same stock at two prices, your cost basis becomes the weighted average — total dollars invested divided by total shares. Buying more at a lower price ("averaging down") pulls your average cost — and your break-even — below the first purchase, but it also commits more money to a position that's currently down.
Only if your reason for owning the stock still holds. It lowers your break-even, but it also increases your exposure to a position the market is currently marking down. Don't average down out of hope.
This covers two lots. For many purchases, keep a running total of dollars invested and shares — the average is always total cost ÷ total shares.
Related: stock profit calculator · dividend yield calculator · dollar-cost averaging calculator · all free calculators.
More free retirement & investing tools — no signup, works on any device.
Yes. The Stock Average Calculator is completely free, runs in your browser, and never asks for a signup, email, or download. Enter your numbers and the result updates instantly.
It uses standard formulas and recalculates the moment you change a value, so the math is exact for the inputs you enter. Treat the result as a reliable planning estimate; for decisions with legal or tax consequences, confirm the figures with a qualified professional.
Yes. The calculator is mobile-friendly and works on any phone, tablet, or computer — there is no app to install and nothing to save.
Yes. Scroll to “Add this free calculator to your site” above and copy the embed snippet to place the live calculator on your blog or website for free.
Last reviewed: September 2026. Free to use, no signup — Stock Average Calculator by ToolWise Digital.
Copy the snippet to embed the live calculator on your blog or website — free for any site. The small “Calculator by ToolWise Digital” credit line keeps it free; you're welcome to remove it, but we appreciate you leaving it.
Ready-made Google Sheets & Excel trackers for money, taxes, and small business — each with a free phone version.
Browse the shop →Subscribe and we'll email you our Simple Monthly Budget (Google Sheets & Excel, plus a phone version) — free. Then the occasional short note on pricing, bookkeeping, and the money side of a small business. No spam — unsubscribe anytime.