Stock Average Calculator
Compute your weighted-average buy price across multiple purchases of a stock.
Weighted average of your buy prices across all transactions; ignores brokerage, charges, and taxes.
Independent · No commissions · No fund-house data — how the numbers are computed
How it works
This calculator finds your true average buy price when you have bought the same stock more than once at different prices. Add each transaction's quantity and price — it computes the weighted average price, total quantity and total amount invested. Buying 100 shares at ₹50 and 200 at ₹55 gives an average of ₹53.33 on 300 shares, not the ₹52.50 a simple average of the two prices would suggest.
The average is weighted by quantity: total money invested divided by total shares held. Larger lots pull the average toward their price, which is why a small dip-buy moves a big position's average less than intuition expects. The result is the reference price for your position — the market price above it means the position is in profit, below it a loss.
The calculator ignores brokerage, statutory charges and taxes, so the true cost basis sits slightly above the computed average. It also applies to averaging in either direction: buying more after a fall lowers the average ("averaging down"), and adding after a rise lifts it — both are just the same weighted arithmetic.
Average price = Σ(qᵢ × pᵢ) / Σqᵢqᵢ and pᵢ are the quantity and price of each buy. The numerator is the total amount invested across all lots and the denominator the total shares held — a weighted average, so larger lots influence the result more.
Frequently asked questions
How is the average stock price calculated across multiple buys?
It is the weighted average: total money invested divided by total shares held, or Σ(quantity × price) ÷ Σ(quantity). Buying 100 shares at ₹50 (₹5,000) and 200 shares at ₹55 (₹11,000) means ₹16,000 invested across 300 shares — an average of ₹53.33. A simple average of the two prices (₹52.50) would be wrong because the second lot, being twice the size, carries twice the weight.
What is averaging down?
Averaging down is buying more of a stock after its price has fallen below your earlier purchase price, which lowers your weighted average cost. Holding 100 shares bought at ₹100 and buying 100 more at ₹60 brings the average to ₹80 — the stock now needs to recover to ₹80, not ₹100, for the position to break even. The arithmetic is the same weighted average this calculator computes; whether the underlying business justifies the added exposure is a separate question.
Why does buying a small quantity barely move my average price?
Because the average is weighted by quantity, not by the number of transactions. Each lot pulls the average toward its price in proportion to its size relative to the whole position. Adding 10 shares at ₹40 to 1,000 held at ₹100 moves the average only to about ₹99.41 — the new lot is 1% of the position, so it gets 1% of the influence. Meaningfully shifting a large position's average requires a comparably large purchase.
Does this average include brokerage and charges?
No — this calculator averages the raw buy prices and ignores brokerage, STT, stamp duty, GST and other transaction charges, so the true cost basis is slightly higher than the computed average. For tax purposes, note also that capital gains in India are computed lot by lot on a first-in-first-out (FIFO) basis per demat account, not against the blended average price.
Go further
The per-trade charges this average deliberately leaves out.
Capital and leverage math for the position you are averaging.
Tax computes gains lot by lot in purchase order, not on your average.
Turn entry-versus-current price into an annualized return.