Finance Average down calculator
Add every purchase of a stock and see your true average price, the break even price once fees are counted, and how much more you would have to buy to reach the average you want.
| # | Price paid | Quantity | Value | Weight | Remove |
|---|---|---|---|---|---|
| 1 | $4,250.00 | 45% | |||
| 2 | $5,250.00 | 55% |
Used for the profit and loss figures. Leave it blank to skip them.
Brokerage as a percentage of each transaction. Set both to zero if your broker charges no commission.
Average price
$38.00
Across 2 purchases totalling 250 shares.
Position now
-$1,750.00
-18.42%. $7,750.00 in your account if you sold at this price.
- Total quantity
- 250 shares
- Total spent
- $9,500.00
- Average cost
- $38.00
- Break even price
- $38.00
- Market value
- $7,750.00
- Price move
- -18.42%
The price a sale has to reach before you get your money back, once both fees are paid. The price is below your break even. Selling today realises the loss; holding does not remove it.
How much more to buy
Averaging down is easy to describe and expensive to do carelessly. Set the average you want and see exactly what reaching it costs.
It has to sit between the price now and your current average.
Averaging down lowers your average price. It does not make the position smaller, and it does not make the company better. You are choosing to own more of something that has fallen, so the reason to buy has to be the business, not the fact that you are down on it.
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Cite this page
Reembun. (2026, August 1). Average down calculator. https://reembun.com/average-down-calculator
How to use it
Set the unit
Quantity in shares, or in lots of 100, whichever matches the way your broker reports the position.
Enter every purchase
One row per buy with the price paid and the quantity. Add a purchase for each extra fill.
Add the price now and your fees
Price now drives the profit and loss figures. Buy fee and sell fee turn the plain average into a real break even price.
Plan the next buy
In How much more to buy, set the average price you want and see the quantity and the cash it takes to get there.
What the average price actually is
The average price of a holding is the total spent divided by the total shares. That sounds obvious until someone averages two prices instead, which is only correct when both purchases were the same size.
average price = Σ (price × quantity) ÷ Σ quantityBuying 100 shares at $42.50 and then 150 at $35.00:
| Purchase | Price | Quantity | Cost |
|---|---|---|---|
| First | $42.50 | 100 | $4,250 |
| Second | $35.00 | 150 | $5,250 |
| Total | 250 | $9,500 |
The average is $9,500 ÷ 250 = $38.00. The midpoint of the two prices is $38.75, and using it would flatter the position by 75 cents a share.
Break even is not the same as your average
Your average price is what the shares cost. Break even is the price a sale has to reach for the money to come back, and it sits higher, because a broker charges you on the way in and again on the way out.
average cost = average price × (1 + buy fee)
break even = average cost ÷ (1 − sell fee)At 0.15% to buy and 0.25% to sell, which is close to standard for an Indonesian broker, an average of Rp 4,080 breaks even at about Rp 4,096. Only 0.4%, but it is the difference between a trade that made nothing and a trade that lost money, and it is invisible on the average price your broker displays. With a commission free US broker both fees are zero and the two numbers are the same.
How much more you would have to buy
This is the question the calculator exists to answer, and the arithmetic is unkind. To move an average from A down to a target T by buying at price P:
quantity needed = (T × shares held − total spent) ÷ (P − T)Continuing the example above, with the price now at $31:
| Target average | Shares to buy | Cash required | Position after |
|---|---|---|---|
| $36 | 100 | $3,100 | $12,600 |
| $35 | 188 | $5,828 | $15,328 |
| $34 | 334 | $10,354 | $19,854 |
| $33 | 625 | $19,375 | $28,875 |
Each dollar of average costs more than the last. Getting from $38 to $35 takes $5,828, which is 61% of what you have already committed. Getting to $33 takes more than doubling the position, and by then two thirds of your money in this stock was invested after it fell.
That table is the honest case against averaging down mechanically. It is not an argument against ever doing it. It is an argument for knowing the price of the decision before you make it.
What averaging down does and does not do
It lowers the price at which you turn a profit. True, and it is the whole point.
It increases the size of your position. Also true, and usually unplanned. A holding you sized at 5% of your portfolio becomes 9% after one average down, and the risk you set out to take has changed without you deciding to change it.
It does not reduce the loss you are carrying. Buy 188 more shares at $31 and the position is down $1,750 before the purchase and $1,750 after it, because the new shares are worth exactly what you just paid for them. What changes is the percentage: 18.4% becomes 11.4%, and it does so because the denominator grew, not because anything was recovered.
It does increase what the next fall costs. A further 10% drop takes $775 off the original 250 shares and $1,358 off the enlarged 438. Averaging down buys a lower break even by putting more money in front of the same risk.
It does not improve the company. A price falls for a reason. Sometimes the reason is the market, and sometimes it is earnings, debt, dilution, a regulator or a departing chief executive. Only the first kind is a discount.
Averaging down against dollar cost averaging
They look similar and behave differently.
Dollar cost averaging is a schedule: a fixed amount at a fixed interval, decided in advance, usually into an index. It buys more units when prices are low because the amount is fixed, and it removes the timing decision entirely.
Averaging down is a reaction: a discretionary purchase, triggered by a fall, in a single stock you already own. It concentrates. The first is a policy for people who have accepted they cannot time the market. The second is an active judgement that this particular price is wrong, and it needs to be defended as such.
Lots and shares
Some markets trade in lots rather than individual shares. On the Indonesia Stock Exchange one lot is 100 shares, so a price of Rp 4,500 means Rp 450,000 for the smallest order you can place. Switch the quantity unit at the top of the calculator and every input and result is expressed in lots.
The averaging arithmetic is identical either way, and the calculator works in shares underneath so the two units always agree.
Before you add to a losing position
Ask what has changed since you bought. If you cannot answer without reference to the price, the fall is the only new information you have, and it is the weakest kind.
Then check the size. Run the number through the position size calculator as though it were a new trade at today’s price, and see whether the combined holding is one you would open from scratch today. If it is not, adding to it is a decision you would not make with cash, made with the money you already have committed.
Nothing on this page is advice about a particular stock. It is arithmetic, and arithmetic is the easy part of this decision.
Common questions
How do you calculate the average price after averaging down?
Add up what every purchase cost you, then divide by the total number of shares. Not the average of the two prices: 100 shares at $42.50 and 150 at $35.00 is $9,500 across 250 shares, so the average is $38.00, not $38.75. The second purchase counts for more because it bought more shares.
Does averaging down reduce my loss?
No. It reduces the price at which the position turns positive, which is a different thing. Adding 188 shares at $31 moves the average from $38.00 to $35.00 and the amount invested from $9,500 to $15,328, while the loss at that moment stays $1,750: the new shares are worth what you just paid. The percentage loss falls from 18.4% to 11.4% only because the denominator grew.
What is my break even price?
The price at which selling returns exactly what the position cost, after the fee on the way in and the fee on the way out. With commission free brokers it equals your average price. Where a broker charges 0.15% to buy and 0.25% to sell, an average of 4,080 breaks even at about 4,096, roughly 0.4% above the number on your statement.
How much do I need to buy to reach a target average?
The quantity is (target × shares held − total spent) ÷ (current price − target). The calculator does it for you and rounds up to a whole tradable unit. The result is often uncomfortable: pulling an average from $38 down to $34 when the price is $31 costs more than the original position did.
Is averaging down a good strategy?
It depends entirely on why the price fell. If the business is unchanged and the market is not, buying more at a lower price is the same decision you made originally, only better priced. If the fall reflects something real about earnings, debt or management, averaging down concentrates your money into a deteriorating position. The calculator answers what it costs, not whether to do it.
Does this handle lots as well as shares?
Yes. Switch the quantity unit to lots and every input and result is expressed in lots of 100 shares, which is how the Indonesia Stock Exchange and several other Asian markets trade. The maths runs in shares underneath either way.
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