Stock Average Calculator

Find your weighted average buy price across multiple stock purchases. Add as many buy lots as you need and instantly see your average cost, total investment, and estimated profit or loss at any target price.

Your Stock Average

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Average Buy Price
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Total Shares
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Total Invested
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Buy Entries

About This Calculator

What it does
Calculates the weighted average buy price across multiple stock purchases at different prices and quantities. Also shows total shares owned, total amount invested, and optional profit/loss at a target sell price.
Inputs required
Buy price and quantity for each purchase lot. Optional: brokerage per trade, target sell price.
Outputs shown
Weighted average buy price, total shares, total amount invested, number of buy entries, optional break-even price (with brokerage), estimated P&L and return % at target sell price, per-lot contribution table.
Formula used
Average Buy Price = Total Amount Invested ÷ Total Quantity. Total Amount Invested = Σ (Buy Price × Quantity) for each lot. With brokerage: add brokerage per trade to each lot's amount before summing.
Assumptions
All purchases are for the same stock/instrument. Brokerage is a flat amount per trade (not percentage). Tax, STT, and other regulatory charges are not included unless added to the brokerage field. Fractional shares supported.
Last updated
3 March 2026

How to Use This Calculator

  1. Enter your first buy. Fill in the buy price and quantity for Share 1.
  2. Add more buys. Click Add More to add a row for each additional purchase at a different price.
  3. Optional – add brokerage. Open Advanced Options and enter brokerage per trade to see the true break-even sell price that covers your charges.
  4. Optional – enter target sell price. Enter the price at which you plan to sell to instantly see estimated profit/loss and return percentage.
  5. Click Calculate. Results appear with your average buy price, totals, and a per-lot breakdown table.
  6. Add or remove lots anytime. Adjust any entry and recalculate — the table and results update instantly.

What Is Stock Averaging?

Stock averaging is the practice of buying shares of the same company at different prices over time. Because you accumulate shares at varying prices, your actual cost per share is the weighted average — not a simple average — of all your purchase prices.

Knowing your average buy price is essential for:

  • Calculating profit or loss when you sell — your gain is (Sell Price − Average Buy Price) × Quantity.
  • Planning your next buy — see exactly how a new purchase at today's price would affect your average cost.
  • Tax reporting — cost basis for capital gains tax is based on your average acquisition price in most jurisdictions.
  • Setting stop-loss and target levels — you need to know your average cost to set meaningful exit levels.

Weighted Average Price Formula

Average Buy Price = (P₁×Q₁ + P₂×Q₂ + … + Pₙ×Qₙ) ÷ (Q₁ + Q₂ + … + Qₙ)

Where Pᵢ is the buy price of lot i and Qᵢ is the number of shares bought in lot i.

With brokerage charges:

Total Invested = Σ (Pᵢ × Qᵢ + Brokerage per trade)
Break-Even Price = Total Invested ÷ Total Quantity

The break-even price is slightly higher than the average buy price when brokerage is included — it is the minimum price at which you can sell without a loss.

Worked Example

Suppose you bought shares of a company in two lots:

  • Buy 1: 11 shares at ₹890 → ₹9,790
  • Buy 2: 17 shares at ₹900 → ₹15,300

Total Quantity: 11 + 17 = 28 shares

Total Invested: ₹9,790 + ₹15,300 = ₹25,090

Average Buy Price: ₹25,090 ÷ 28 = ₹896.07 per share

Note: A simple average of ₹890 and ₹900 would give ₹895. The weighted average is slightly higher (₹896.07) because you bought more shares at the higher price of ₹900.

If you later sell all 28 shares at ₹950:

P&L: (₹950 − ₹896.07) × 28 = +₹1,510 profit (6.0% return)

Averaging Down vs Averaging Up

Averaging Down

When the stock price falls below your original buy price, buying more shares lowers your average cost. This means the stock needs to recover less ground before you break even or profit.

  • When it helps: You have high conviction in the company's fundamentals and the price drop is temporary or market-driven.
  • When it hurts: You average down into a company that is fundamentally deteriorating — compounding your losses.

Averaging Up

Buying more shares at a higher price than your original purchase raises your average cost but adds to a winning position.

  • When it helps: The company is growing strongly and the stock is trending upward — adding more at a higher price can still generate strong returns if the trend continues.
  • When it hurts: You chase a stock near its peak and pay an inflated average cost, leaving little upside.

Frequently Asked Questions

A stock average calculator computes the weighted average price you paid across multiple purchases of the same stock. When you buy shares at different prices on different dates, the average buy price accounts for how many shares you bought at each price — giving a more accurate cost basis than a simple arithmetic mean.
Average Buy Price = Total Amount Invested ÷ Total Quantity Purchased. Total Amount Invested = Sum of (Buy Price × Quantity) for each purchase lot. For example, buying 11 shares at ₹890 and 17 shares at ₹900 gives: Total = ₹9,790 + ₹15,300 = ₹25,090. Average = ₹25,090 ÷ 28 = ₹896.07 per share.
Averaging down means buying more shares of a stock after its price has fallen below your original purchase price. This lowers your average cost basis, so you need a smaller price recovery to break even or profit. However, it only makes sense if the company's fundamentals remain intact.
Averaging up means buying more shares of a stock after its price has risen above your original purchase price. This raises your average cost but adds to a winning position. It is a disciplined strategy when a stock is trending strongly and you want to increase your exposure.
The basic average price formula excludes brokerage. For the true break-even sell price (the minimum you need to charge to cover all costs), add brokerage per trade to each buy. Use the Advanced Options in this calculator to include brokerage charges automatically.
This calculator supports unlimited lots. Click Add More to add as many buy entries as needed. Each entry requires a buy price and quantity. You can remove any entry using the Remove button next to it.
Cost basis is the total amount you paid to acquire an investment, including brokerage and taxes. It is used to calculate capital gains for tax purposes: Capital Gain = Selling Price − Cost Basis. A lower cost basis means a higher taxable gain when you sell. Weighted average cost is one of the standard methods for calculating cost basis.
Use this calculator when you have bought the same stock multiple times at different prices and want to know: your average cost per share, your total investment in that stock, the profit or loss you would make at a given sell price, and whether a new purchase would average up or average down your position.

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Calculator Category

This tool belongs to Finance Calculators. Browse similar tools for investment, loan, and business finance calculations.

Results are for informational and planning purposes only. This is not investment advice. Stock prices can fall as well as rise. Past purchase prices do not guarantee future returns. Always consult a qualified financial advisor before making investment decisions.