How this calculator works
- Step 1Add the shares30A larger buy lot counts more than a smaller one.
- Step 2Add acquisition outlay₹2,600.00Quantity times price, plus separately entered costs.
- Step 3Divide outlay by shares₹86.67This is cost per share across the entered buys.
Each share has equal weight; each buy price does not. Buying different quantities at different prices means the combined average is total acquisition outlay divided by total shares, not a plain average of the quoted prices.
Enter matching lists for share quantities and prices. Optional lot costs are total rupee charges for each buy, not per-share fees or percentages. Blank costs mean the calculation deliberately ignores them.
Worked example: buys of different sizes
- Each trade
trade value = shares × buy price- Combined outlay
C = sum(trade values) + sum(lot costs)- Cost-inclusive average
average = C ÷ total shares
- Lot 110 shares at ₹100.00₹1,000.00
- Lot 220 shares at ₹80.00₹1,600.00
- Total shares30
- Total trade value₹2,600.00
- Total entered acquisition costs₹0.00
- Outlay divided by shares₹86.67
The cheaper lot contains more shares, so it pulls the combined average towards its price. Rearranging the list does not change the result, provided each quantity keeps its matching price and cost.
The ledger shows every lot’s share count, trade value, costs and outlay. Use it to catch a shifted row or duplicated cost before interpreting the headline average.
Price-only and cost-inclusive averages
- Price-only average₹86.67Weights prices by the purchased share quantities.
- Average with the cost example₹87.67Includes total additional costs of ₹30.00.
- Total outlay with those costs₹2,630.00The amount reconciled across both entered lots.
Acquisition costs increase outlay without adding shares. That makes the cost-inclusive average higher than the price-only average when costs are positive. The calculator shows both so the basis is never hidden.
This is not a statutory tax cost basis or a broker statement. It does not decide which charges are deductible, apply FIFO to sold shares, or adjust for corporate actions. Use appropriately adjusted inputs and authoritative records for those purposes.
Solve a hypothetical next price
Target mode fixes the extra quantity and solves the next price needed for an exact cost-inclusive average.
The target question does not look up a quote or decide whether a further purchase is sensible. It asks which hypothetical price would make the combined outlay, including all entered costs, equal the chosen target multiplied by the combined share count.
- Solve the weighted-average equation
next price = [target × (current shares + extra shares) − current outlay − extra costs] ÷ extra shares
- Current acquisition outlay₹2,600.00
- Target cost-inclusive average₹80.00
- Additional shares10
- Combined shares after the hypothetical buy40
- Required combined outlay₹3,200.00
- Hypothetical next price per share₹60.00
Additional costs reduce the share price that would achieve the same target. They are included inside the equation, not added afterwards. The solved price is displayed to six decimals because a two-decimal quote may not reproduce the target exactly.
An actual exchange can impose a different tick size or trading restriction. This tool neither rounds to an exchange tick nor claims the hypothetical price is available.
When a target is not feasible
Even a zero-price extra lot may not lower the average far enough for the entered quantity.
If the target requires a negative next price, the calculator reports that the scenario is infeasible. It does not silently increase the extra quantity, remove costs or show a zero quote as though the target had been met.
An exactly zero solved price is a mathematical boundary and is labelled as such. It is not a real free-share offer. Higher target averages can also produce a solved price above current lot prices; that is still arithmetic, not a trading suggestion.
Input limits and privacy
Match all lot lists in order and avoid thousands-grouping commas inside individual entries.
Use commas, semicolons, spaces or new lines as separators. For one thousand, write 1000 rather than 1,000. Prices and costs use decimal points. Empty comma-separated cells are invalid rather than silently discarded.
You can enter up to one hundred buy lots. Quantities are positive whole shares; fractional shares are not supported. Use one security, one currency and a consistent adjusted share basis. Do not mix pre-split and post-split quantities without adjusting them yourself.
Holdings and target inputs stay in the browser. The URL fragment keeps the lists out of ordinary server requests and analytics. Anyone who receives the full address can still read the entries, so share it only intentionally.
Common stock-average mistakes
Mistake: Take a simple average of buy prices when quantities differ.
Instead: Weight each price by its share quantity, or divide total trade value by total shares.
Mistake: Enter a total lot fee as a per-share amount.
Instead: Enter each lot’s full acquisition costs once in the costs list.
Mistake: Treat a lower acquisition average as proof that a loss disappeared.
Instead: It changes the cost per share and exposure, not the market value of existing holdings.
Mistake: Use the target price as a recommendation or live quote.
Instead: Read it only as a solved hypothetical equation, including its costs and quantity assumptions.
Sources and independent checks
Frequency-expanded shares check the weighted average; appending the solved lot checks the inverse.
The weighted-average equation follows OpenStax’s frequency treatment of the mean. Target mode rearranges that equation. Golden tests compare lot ledgers with individual-share expansion, then append hypothetical lots to reconstruct the target. Sources and review details are listed below.
Related trading tools
An average price includes costs. Charges, returns and timing each have a tool.
To see every charge on an equity trade, including STT and stamp duty, use the brokerage calculator. For the return on a holding with dated buys and sells, try the XIRR calculator.
Read how we test our calculators, or browse more money calculators.