Stock Average Price Calculator
Combine purchases of one security into price-only and fee-inclusive averages. See total shares, consideration, fees and outlay in a consistent major currency unit.
Purchase arithmetic, not a valuation, tax basis, exit break-even price or personalized investment advice. No sales, FX or corporate-action processing.
Purchase-weighted averages
Enter every purchase field and confirm the basis, or load the verified example.
A purchase average is not a universal tax basis, investment return, profit figure or exit break-even price. No selling costs or tax adjustments are included. Averaging down adds capital exposure and does not remove risk.
120 significant decimal digits internally; half-even currency display at 2 places with tiny nonzero markers. Displayed components round independently and may not add exactly. Direct fee increment preserves small fees independently of rounded averages. No financial values are saved, sent or placed in URLs. Positive quantities/prices, nonnegative explicit fees; at most 100 rows. Monetary totals capped at 2e26 and averages at 2e24, with unsupported outputs rejected rather than clipped.
Understand the purchase average
Quantities weight each price. Keep purchase fees separate and do not confuse the resulting average with a tax-lot method or a sale profit calculation.
Read the complete Stock Average Price guideFormula and methodology
Q = Σq; C = Σ(q×p); F = Σf.
Price-only = C/Q; fee-inclusive = (C+F)/Q.
Direct fee increment = F/Q.
Multiply each quantity by its purchase price and sum those products to obtain purchase consideration C. Sum quantities to obtain Q and supplied purchase fees to obtain F. Price-only average is C/Q. Fee-inclusive purchase average is (C+F)/Q. Fees are added once to total outlay, not once per share.
Verified worked examples
Consider ten shares at 100 and twenty shares at 80, with separate purchase fees of 2 and 3 in the same monetary unit. The quantity is 30, consideration is 2600, fees total 5 and outlay is 2605. Price-only average is 86.666666… and fee-inclusive average is 86.833333… per share. The direct fee increment is 0.166666… per share.
Inputs and interpretation
Choose the display market and currency. Enter every quantity, price and purchase fee using an ungrouped decimal point, then confirm the consistent purchase-only basis. A blank fee is missing information; it never becomes zero automatically. Load the worked example to check the controls, then replace every assumption before interpreting your own purchases.
Assumptions and limitations
All supplied lots must represent purchases of one identical security. Quantities and prices are positive, fees are nonnegative and every amount uses the same major currency unit. There is no live ticker lookup, automatic exchange rate, sales ledger, short position, borrowing cost or account synchronization.
Supported domain and common mistakes
The calculator accepts one through 100 purchase rows. Quantity and price range from 0.000000000001 through 1000000000000; fees range from explicit zero through 1000000000000. Strings are trimmed, limited to 48 characters and 12 fractional decimal places. Grouping separators, currency symbols, percentages, negative values and exponent notation are rejected rather than reinterpreted.
Do not average prices without weighting quantities. Do not enter a total trade value as the price per share, a per-share charge as the total purchase fee, or a fee percentage as a monetary amount. A ten-share purchase with a total fee of 2 uses 2 in the fee field, not 20 and not 0.2 unless that is the actual total charge.
Frequently asked questions
How is the average weighted?
Must I enter a zero purchase fee?
Can I enter sales or negative quantities?
Does changing the currency convert my prices?
Is this my tax basis or exit break-even price?
How are tiny purchase fees handled?
Are my purchase records stored or sent?
Sources and educational scope
The Capital Intelligence provides financial calculators and educational explanations, not personalized investment advice. It is personally operated by Arunangshu Das, an individual in India. An arithmetic average does not establish suitability, safety or future returns. Consult the appropriate professional for decisions that depend on personal circumstances.
Reviewed . AI-assisted content under operator editorial responsibility; no independent expert financial review is claimed.