Stock Average Down Calculator
Average cost per share across several purchases of one stock, the new average after buying more, and the gain or loss at a current price you enter. How it works
Use the Stock Average Down Calculator
About the Stock Average Down Calculator
Buy 100 shares at $50 and another 100 at $30 and your average cost is $40.00 a share: $8,000.00 of total cost ÷ 200 shares. The stock average down calculator adds up any number of purchases of one stock, shares × price for each, and divides by the total shares.
Averaging down 100 shares bought at $50 with a second buy at $30
| Shares bought at $30 | Total shares | Total cost | New average cost |
|---|---|---|---|
| 50 | 150 | $6,500.00 | $43.3333 |
| 100 | 200 | $8,000.00 | $40.00 |
| 200 | 300 | $11,000.00 | $36.6667 |
| 300 | 400 | $14,000.00 | $35.00 |
Each extra share at $30 pulls the average toward $30 but never below it. Commissions are not included.
Frequently asked questions
- How do I calculate my average cost per share?
- Multiply each purchase’s shares by its price, add the costs and divide by the total number of shares. 10 shares at $150 and 15 at $120.50 cost $3,307.50 for 25 shares, an average of $132.30. The Purchase breakdown table under the result shows each buy’s cost and the average after it: 100 shares at $50, then 100 at $30, then 200 at $30 take the average from $50.00 to $40.00 to $35.00.
- How many shares do I need to buy to average down?
- Shares to buy = shares you hold × (current average − target average) ÷ (target average − new price). Holding 100 shares at $50 and buying at $30, a $40 target needs 100 × 10 ÷ 10 = 100 shares and a $35 target needs 100 × 15 ÷ 5 = 300. The calculator does not solve this for you, so enter the result as a new row to check it: those rows give $40.00 and $35.00. The target must be above the new price.
- Is averaging down the same as dollar-cost averaging?
- No. Averaging down is not dollar-cost averaging: it means buying more after the price has fallen, to lower your average cost. Dollar-cost averaging means investing a fixed amount on a schedule, whatever the price.
- Does buying at a higher price raise my average cost?
- Yes. 100 shares at $50 plus 50 at $60 average $53.3333. The calculator works the same way in both directions.
- How do I see my gain or loss at today’s price?
- Type the price in Current price per share. With 100 shares at $50 and 100 at $30 (average $40.00) and a price of $35, the market value is $7,000.00, the unrealized loss -$1,000.00 (-12.5%) and the gap to break-even $5.00 per share, a 14.29% rise from $35. At $45 the gain is +$1,000.00 (+12.5%) and the page says the position is at or above break-even. The price is not looked up and does not change the average cost.
- Are my purchases saved?
- Yes, in this browser’s local storage, with the current price you typed, so they are still there when you come back. Clear Saved Values removes them.
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