Stock average calculator for stocks, ETFs & crypto
Stop guessing how much to invest. Know your exact break-even price and new average cost before you commit a single dollar — whether you're averaging down or sizing a DCA entry.
avgr.app provides mathematical calculations only. Not financial advice.
Free forever · No account needed
See it in action
Watch the calculator work
Enter a position, drag the slider, and see the diminishing-returns curve update in real time.
How it works
Know your break-even in three steps
See your exact new average cost, break-even price, and the full diminishing-returns curve — before you commit a single dollar.
Enter your position
Tell avgr how many shares you hold, your average buy price, and the current market price. Works with any stock, ETF, or crypto — no ticker lookup needed, just the numbers.
Shares owned
Avg buy price
Market price
See exactly where each dollar stops helping
avgr plots the full diminishing-returns curve — so you can see how much your average price drops as you add capital, and exactly where returns become marginal. There is a hard mathematical ceiling no amount of money can cross.
Each dollar you add helps less than the one before. The curve never crosses the dashed line.
Know the exact number before you buy
Drag the slider to any capital amount. Instantly see your new average price, break-even point, cost basis improvement, shares added, and capital efficiency — all in real time. No guesswork, no spreadsheets.
New avg
$163.33
was $180.00
Improvement
$16.67
−9.26%
Capital
$3,100
20 shares
Shares
20
added
Efficiency
0.537%
per $100
The concept
What is an average down calculator?
An average down calculator helps investors compute their new average cost per share after buying additional shares at a lower price. When a stock drops below your original buy price, purchasing more shares lowers your cost basis — but the improvement shrinks with every dollar you add.
avgr goes further than a simple calculator. It plots the full diminishing-returns curve so you can see exactly how much each additional dollar improves your average price — and where the returns become marginal. It also shows your break-even point: the new average price you need to recover your position.
Works for any asset priced per unit — stocks, ETFs, index funds, and crypto. No ticker lookup required; the calculator works entirely from the numbers you provide.
Key concepts
Strategy comparison
Average down vs dollar cost averaging (DCA)
Both strategies involve buying more shares over time, but they serve different goals and carry different risks.
Averaging down
You buy more shares after the price drops below your original purchase price. The goal is to lower your average cost basis so you need a smaller recovery to break even.
- ·Triggered by a price drop in a position you already hold
- ·Lowers your break-even price immediately
- ·Returns diminish sharply — the curve always flattens
- ·High risk if the stock continues to fall
avgr calculates the exact new average price, break-even, and diminishing-returns curve for this strategy.
Dollar cost averaging (DCA)
You invest a fixed amount on a regular schedule regardless of price — weekly, monthly, or quarterly. The goal is to smooth out entry price over time rather than react to price movements.
- ·Not triggered by price — follows a fixed calendar schedule
- ·Reduces timing risk over the long term
- ·Average price moves gradually with the market
- ·Lower emotional pressure than reactive buying
DCA is a passive, schedule-driven strategy. avgr is designed for the reactive, position-based scenario.
FAQ
Common questions
Everything you need to know about averaging down, how the calculator works, and what it can and cannot tell you.
Concept
What is averaging down in stocks?
What is averaging down in stocks?
Averaging down means buying more shares of a stock after its price has fallen below your original purchase price. Each new purchase lowers your weighted average cost per share (cost basis). The crucial insight is that the improvement follows the law of diminishing returns — every dollar you add helps less than the dollar before it, and there is a hard ceiling no amount of capital can cross.
Math
Why does the improvement curve flatten out so quickly?
Why does the improvement curve flatten out so quickly?
Because your new average is a weighted mean of all your purchases. Your existing position anchors the result — as you add more shares, each new purchase represents a smaller fraction of your total holding, so its influence on the average shrinks. The mathematical ceiling is the current market price: no amount of capital can push your average cost below the price you are paying today.
Compatibility
Can I use this for ETFs, index funds, or crypto?
Can I use this for ETFs, index funds, or crypto?
Yes. avgr works with any asset priced per unit — stocks, ETFs, index funds, REITs, ADRs, or anything else you can express as shares owned + average buy price + current price. There is no ticker lookup; the calculator only works with the numbers you provide, so the math is identical regardless of asset class.
Disclaimer
Is avgr financial advice?
Is avgr financial advice?
No. avgr is a pure math tool — it computes arithmetic relationships between numbers you enter. It does not recommend whether you should buy, sell, or hold any security. A lower average cost per share does not guarantee profitability; a stock can keep falling regardless of how low your cost basis is. Always consult a qualified, licensed financial adviser before making investment decisions.
Accuracy
How accurate are the calculations?
How accurate are the calculations?
avgr uses Elixir's Decimal library with 28-digit precision to eliminate the floating-point rounding errors that affect spreadsheets and most online calculators. Shares are always floored to the nearest whole unit (discrete share purchases). The curve is plotted at 121 evenly spaced points across the full capital range, then interpolated at 60fps client-side.
Stop sizing your buys by instinct
See the exact curve. Know the real improvement. Decide with data.
Open the calculatorFree forever · No account needed