New average cost
Multiply current shares by the current average cost, add the value of the new buy, and divide by total shares after the buy.
Formula guide
Break-even logic
This page treats the new blended average cost as the break-even price before fees, taxes, and slippage.
Cost reduction
The cost reduction percentage compares the old average cost against the new blended average cost.
What it does not include
Broker commissions, taxes, currency conversion costs, and corporate actions are excluded from the simplified model.
When to use this tool
Comparing multiple add-on plans
Test whether buying more shares now materially improves your break-even level or only adds risk without enough cost improvement.
Checking recovery targets
Use the new blended cost to decide what price move is required to recover capital after a drawdown.
Planning staged entries
Run the tool repeatedly with different lower prices and share sizes to compare several potential entry layers.
Reviewing capital usage
The capital bars show how much new money the position requires versus what is already deployed.
Related calculators
FAQ
What is averaging down?
Averaging down means buying more shares at a lower price than your current average cost so the blended cost basis decreases.
Does this calculator include trading fees?
No. It shows the clean cost-basis math first. If your broker charges meaningful fees, keep a small buffer above the break-even number.
Can I use this for ETFs as well as stocks?
Yes. The math is identical as long as you enter the correct share counts and prices.
Why can averaging down still be risky?
Because lowering the average cost also increases total capital exposure. If the thesis is broken, the larger position can deepen losses.