How is this calculated?

This calculator uses compound interest formulas, historical market return assumptions, and standard financial planning methodologies to project your investment growth over time.

What rate of return should I assume?

A balanced portfolio has historically returned 7-10% annually before inflation (about 5-7% after). Conservative estimates use 6-7%, aggressive portfolios may assume 8-10%. Lower is safer for planning.

Should I invest or pay off debt first?

Pay off high-interest debt (above 7%) first. For lower-rate debt like mortgages, investing often makes more sense mathematically, but being debt-free has psychological benefits too.

Stock Average Price Calculator

Calculate your average cost per share across multiple stock purchases to track your cost basis.

Your data stays in your browser. Nothing is stored or sent to any server.

Built by Abiot Y. Derbie, PhD — Postdoctoral Research Fellow. Quantitative researcher specializing in statistical modeling and data-driven decision systems.

Enter Your Details

Buy 1: Shares

Buy 1: Price/Share

Buy 2: Shares

Buy 2: Price/Share

Buy 3: Shares

Buy 3: Price/Share

Current Price/Share

Average Cost Per Share

Total Shares

Total Invested

Current Value

Gain/Loss

What This Means For You

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This calculator is for informational and educational purposes only. Results are estimates based on the information you provide and standard financial formulas. This is not financial advice. Consult a qualified financial advisor for decisions specific to your situation. Full Disclaimer

Things to Know

Essential concepts for understanding your results

Dollar Cost Average

How does averaging down affect your cost basis?

Average Price = Total Amount Invested ÷ Total Shares Owned. Buying 50 shares at $80 ($4,000) then 50 more at $60 ($3,000): 100 shares for $7,000 = $70 average, not the $70 midpoint. The second purchase at a lower price pulls the average down significantly. This is the mathematical basis of dollar-cost averaging — buying at regular intervals automatically ensures you buy more shares when prices are low and fewer when high.

When Averaging Down Works

Is averaging down a good strategy?

Averaging down works for index funds and diversified ETFs — broad markets always recover eventually, so buying at lower prices improves long-term returns. It is dangerous for individual stocks — a stock dropping from $100 to $50 might go to $0 (Enron, Lehman Brothers, Silicon Valley Bank). Averaging down on a failing company just increases your losses. The rule: average down on the market, never on a single stock unless you have high conviction based on fundamental analysis.

Lot Selection

How does lot selection affect taxes when selling averaged positions?

When selling part of an averaged position, you can choose specific lots (highest cost first = minimize gains, lowest cost first = maximize gains for tax-loss harvesting) or let your broker use FIFO (first-in, first-out — default). If you bought at $80 and $60 then sell at $70: selling the $80 lot realizes a $10 loss (deductible), while selling the $60 lot realizes a $10 gain (taxable). Specific lot identification can save thousands in taxes — always review lot options before selling.

Stock Average Price Calculator: Find Your Cost Basis Across Multiple Purchases

Whether you are looking for a stock average price estimator, calculate stock average price, how to calculate stock average price, stock average price formula, free stock average price calculator, or stock average price returns — this free stock average price calculator provides accurate estimates to help you plan and make informed financial decisions.

A stock average calculator computes your weighted average cost per share when you have bought the same stock at different prices over time. Your average cost (cost basis) determines your profit or loss when selling and your capital gains tax obligation.

Formula: Average Price = Total Amount Invested ÷ Total Shares Owned

Enter each purchase (shares and price) above. The calculator shows your weighted average cost, total investment, and current gain/loss at any target price.

Example Average Cost Calculation

Purchases: 50 shares at $40 = $2,000. 30 shares at $35 = $1,050. 40 shares at $45 = $1,800. 25 shares at $30 = $750.

Total invested: $5,600. Total shares: 145. Average cost: $5,600 ÷ 145 = $38.62/share.

If the stock is currently at $50: unrealized gain = ($50 - $38.62) × 145 = $1,650 (29.5% return). At $35: unrealized loss = ($35 - $38.62) × 145 = -$525 (-9.4%).

"Averaging down" vs "averaging up": Buying more shares at a lower price (averaging down) reduces your average cost, requiring less recovery to break even. Buying the $30 batch reduced the average from $40 to $38.62. However, averaging down on a declining stock is only smart if your investment thesis remains intact — if the company's fundamentals are deteriorating, buying more magnifies losses. Averaging up (buying more as the price rises) increases your average cost but is a sign of a winning investment.

Frequently Asked Questions

How do I calculate my average stock price?

Total dollars invested across all purchases ÷ total shares owned = average cost per share. Enter each purchase lot above for instant calculation. Your brokerage also tracks cost basis — check your account's "positions" or "tax lots" page for the official figure used for tax reporting.

Does averaging down work?

It reduces your breakeven price, requiring less recovery to profit. Buying 100 shares at $50, then 100 more at $30: average drops from $50 to $40. The stock only needs to recover to $40 (not $50) to break even. However, averaging down only works if the stock eventually recovers. For fundamentally strong companies in a temporary dip: effective strategy. For declining businesses: throwing good money after bad.

How does cost basis affect my taxes?

Your cost basis determines your capital gain or loss when selling. Sell at $50 with $38.62 average cost: $11.38/share gain taxed at 0-20% (long-term) or 10-37% (short-term). When selling partial positions, you can choose specific lots: sell higher-cost lots first to minimize the taxable gain, or sell lower-cost lots to maximize the deductible loss. Your brokerage's default is usually FIFO (first in, first out).

Should I average down or cut my losses?

Ask: has my original investment thesis changed? If the thesis is intact and the decline is market-wide or temporary: averaging down is rational. If the company's fundamentals have deteriorated (revenue declining, competitive position weakening, management issues): cutting losses preserves capital for better opportunities. A common mistake: emotional averaging down because you "can't accept the loss" — this turns a small loss into a large one.

What is dollar cost averaging into a single stock?

Investing fixed amounts at regular intervals into the same stock — automatically buying more shares when cheap and fewer when expensive. It is the same concept as DCA into index funds but with concentrated single-stock risk. DCA works best for broad-market index funds where long-term recovery is virtually certain. For individual stocks: DCA amplifies risk because single companies can go to zero. See our DCA Calculator.

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