Stock Average Calculator — Share Average Price & Average Down
Work out the average buy price of any NSE or BSE stock you bought in more than one lot. See exactly how many shares you need to buy to average down (or up) to a target price, and how FIFO decides your taxable gain when you sell.
What is your average share price?
Your average share price (also called average buy price or average cost) is the total amount you paid for a stock divided by the number of shares you own. It is your break-even price: above it you are in profit, below it you are at a loss. Your broker's holdings screen shows the same number as "Avg. price".
A share average calculator matters when you buy the same stock more than once at different prices, whether through a fall, a staggered entry, or a monthly stock SIP. Each purchase pulls your average towards its own price, in proportion to how many shares it added.
How to use this calculator
- Average Price: enter each buy (quantity and price). You get your average, total invested and, if you enter today's price, your profit or loss and the rise needed to break even. Tick Include charges to see your true cost.
- Average Down / Up: enter your current holding and the market price, then either a target average or a fixed amount to invest. You get the number of shares to buy, the new average, and how much bigger your position becomes.
- Sell & Tax (FIFO): enter dated buys and a sale. You get the gain your holdings screen shows next to the gain the Income Tax Department sees, split into STCG and LTCG with an estimated tax.
Stock average formula
Q = shares bought in each purchase, P = price paid in that purchase.
To include costs: add all buy-side charges to the top line before dividing.
Worked example
Suppose you bought the same stock three times as it fell:
| Purchase | Shares | Price | Amount |
|---|---|---|---|
| 1st buy | 100 | ₹1,500 | ₹1,50,000 |
| 2nd buy | 50 | ₹1,350 | ₹67,500 |
| 3rd buy | 150 | ₹1,200 | ₹1,80,000 |
| Total | 300 | ₹3,97,500 |
Average price = ₹3,97,500 ÷ 300 = ₹1,325. If the stock now trades at ₹1,280, you are down ₹45 a share (₹13,500 in total), and the stock needs to rise 3.52% for you to break even.
How many shares to buy to average down
To bring your average down to a target price, solve the average formula for the unknown quantity. With Q shares held at average A, buying n more shares at the market price P gives a new average of (Q×A + n×P) ÷ (Q + n). Setting that equal to your target T and solving for n gives:
Amount needed = n × P. Round n up to a whole share.
Only works when T is between P and A. The same formula handles averaging up when P is above A.
Example: 200 shares at ₹850, stock now at ₹620
To reach a ₹700 average: n = 200 × (850 − 700) ÷ (700 − 620) = 30,000 ÷ 80 = 375 shares, costing ₹2,32,500. Your break-even rise falls from 37.1% to 12.9%. But your money in this one stock grows from ₹1,24,000 to ₹3,56,500, about 2.9 times as much.
Here is what each target average costs:
| Target average | Shares to buy at ₹620 | Amount needed |
|---|---|---|
| ₹800 | 56 | ₹34,720 |
| ₹750 | 154 | ₹95,480 |
| ₹700 | 375 | ₹2,32,500 |
| ₹650 | 1,334 | ₹8,27,080 |
| ₹630 | 4,400 | ₹27,28,000 |
The cost rises sharply as the target gets closer to the market price, because each new share only pulls the average part of the way. Your average can never reach the market price, however much you buy. The first ₹50 of reduction costs ₹34,720. The last ₹20 (₹650 → ₹630) costs over ₹19 lakh more.
Averaging down vs averaging up
| Averaging down | Averaging up | |
|---|---|---|
| When | Price is below your average | Price is above your average |
| Effect on average | Lowers it | Raises it |
| You are adding to | A position that is losing | A position that is winning |
| Main risk | The price keeps falling and too much of your money ends up in one stock | Buying near a short-term top |
| Better suited to | Sound businesses in a broad market fall, within a pre-set allocation limit | Trend followers adding to confirmed strength |
Averaging down is not a strategy on its own. It only helps if the stock recovers. Before adding, ask whether you would buy the stock fresh at today's price if you didn't already own it. If not, a lower average just makes the loss bigger. A common rule is to cap any single stock at 5–10% of your portfolio. Use our Position Size Calculator to size the extra buy against your risk limit.
Equal-amount buying: why your average beats the average price
If you invest a fixed rupee amount each time, as in a monthly stock SIP or mutual fund SIP, you automatically buy more shares when the price is low and fewer when it is high. Say you invest ₹10,000 in three months at ₹100, ₹80 and ₹125:
| Month | Price | Invested | Shares bought |
|---|---|---|---|
| 1 | ₹100 | ₹10,000 | 100 |
| 2 | ₹80 | ₹10,000 | 125 |
| 3 | ₹125 | ₹10,000 | 80 |
| Total | ₹30,000 | 305 |
Your average cost is ₹30,000 ÷ 305 = ₹98.36, lower than the ₹101.67 simple average of the three prices. With equal amounts invested, this always holds (mathematically, your cost is the harmonic mean of the prices). The gap grows when prices swing more. This is rupee cost averaging, and it is why SIPs smooth out entry prices without any timing.
Including brokerage, STT and charges in your average
Your broker's "Avg. price" usually leaves out charges, so your true break-even is a little higher. For delivery (CNC) buys in India, these charges apply on the buy side:
| Charge (delivery, buy side) | Typical rate |
|---|---|
| Securities Transaction Tax (STT) | 0.1% of trade value |
| Stamp duty | 0.015% of trade value |
| Exchange transaction charge | About 0.003% (NSE) |
| SEBI turnover fee | ₹10 per crore |
| GST | 18% on brokerage + exchange + SEBI charges |
| Brokerage | ₹0 to 0.5%, depending on broker |
At zero brokerage, buy-side charges come to roughly 0.12%, about ₹471 on the ₹3,97,500 example above, which lifts the true average from ₹1,325 to about ₹1,326.57. Selling adds another 0.1% STT plus a flat DP charge per stock per day, so a delivery round trip costs roughly 0.25% before brokerage. Rates vary by broker, so take the exact figures from your contract note.
For income tax, brokerage can be added to your cost of acquisition, but STT can't be deducted when you compute capital gains.
Does selling change your average? Holdings average vs FIFO
There are two different "averages", and they serve different purposes:
- Holdings screen (weighted average): when you sell part of a position, the remaining shares keep the same average. This is what most broker apps show.
- Income tax (FIFO): for shares in a demat account, CBDT Circular No. 768 (1998) says the shares bought first are treated as sold first. The cost, holding period and STCG/LTCG class of the shares you sell come from your oldest lots. FIFO is generally applied separately within each demat account.
Example where the two disagree
You bought 100 shares at ₹500 in March 2024 and 100 more at ₹300 in January 2026. Your app shows 200 shares at a ₹400 average. In October 2026 you sell 100 at ₹450.
| Holdings view | Tax view (FIFO) | |
|---|---|---|
| Cost of 100 shares sold | ₹400 each (average) | ₹500 each (the March 2024 lot) |
| Result | Profit of ₹5,000 | Long-term capital loss of ₹5,000 |
| Shares left | 100 at ₹400 | 100 at ₹300 (short-term until Jan 2027) |
Your ITR uses the FIFO figure. In this case the "profit" is a loss for tax, which you can set off against long-term gains and carry forward for up to 8 years if you file on time. Use the Sell & Tax (FIFO) tab to check before you sell, especially near the 12-month mark, where waiting a few days can move a lot from 20% STCG to 12.5% LTCG.
Bonus issues, stock splits and rights issues
| Event | Your shares | Displayed average | Cost for tax | Holding period starts |
|---|---|---|---|---|
| Bonus 1:1 | 100 → 200 | ₹1,000 → ₹500 | Original shares keep ₹1,000; bonus shares cost ₹0 | Bonus shares: from allotment date |
| Split 1:5 (₹10 → ₹2 face value) | 100 → 500 | ₹1,000 → ₹200 | Original cost spread over all 500 shares (₹200 each) | Original purchase date |
| Rights issue | Plus the rights shares | Blended with the rights price | Rights price paid | Rights shares: from allotment date |
Because bonus shares have a nil cost and a new holding period, selling right after a bonus can produce a much bigger short-term gain than your blended average suggests. Enter bonus shares in the FIFO tab as a separate lot at ₹0 on the allotment date.
Capital gains tax on shares: FY 2026-27 quick reference
| Listed equity shares (STT paid) | Holding period | Tax rate |
|---|---|---|
| Short-term capital gain (STCG) | 12 months or less | 20% + 4% cess |
| Long-term capital gain (LTCG) | More than 12 months | 12.5% + 4% cess on gains above ₹1.25 lakh per financial year |
A short-term capital loss can be set off against both STCG and LTCG. A long-term loss can be set off only against LTCG. For shares bought before 1 February 2018, the cost for LTCG may be raised to the market value on 31 January 2018 (grandfathering). For a full computation, use our Capital Gains Tax Calculator.
Five mistakes investors make with average price
- Averaging the prices, not the amounts. Always weight by quantity.
- Treating the average as a target. The market doesn't know your average. A stock has no reason to come back to it.
- Averaging down without a limit. Set a maximum allocation for each stock before the first buy.
- Using the app's average for tax. Capital gains follow FIFO, lot by lot.
- Forgetting charges. On small, frequent buys, STT, stamp duty and DP charges noticeably raise your real break-even.
For a plain mean, median and mode of any list of numbers, use our general Average Calculator. To measure the actual annualised return on a stock you bought in several instalments, use the XIRR Calculator.
