Stock Average Cost Calculator
Calculate your average cost per share across multiple purchases. See unrealized gains/losses and how buying more shares affects your cost basis.
Your Purchases
Current & Target Price
Average Cost Per Share
225 shares total
Position Summary
| Total Shares | 225 |
| Total Cost Basis | $11,375.00 |
| Average Cost/Share | $50.56 |
| Break-Even Price | $50.56 |
| Current Price | $52.00 |
| Unrealized Gain/Loss | +$325.00 (2.86%) |
Purchase Breakdown
| # | Shares | Price | Cost | Current P/L |
|---|---|---|---|---|
| 1 | 100 | $50.00 | $5,000.00 | +$200.00 (4.0%) |
| 2 | 50 | $45.00 | $2,250.00 | +$350.00 (15.6%) |
| 3 | 75 | $55.00 | $4,125.00 | -$225.00 (-5.5%) |
If You Buy More at $52.00
| Add Shares | Cost | New Avg Cost | Change |
|---|---|---|---|
| +10 | $520.00 | $50.62 | +$0.06 (0.1%) |
| +25 | $1,300.00 | $50.70 | +$0.14 (0.3%) |
| +50 | $2,600.00 | $50.82 | +$0.26 (0.5%) |
| +100 | $5,200.00 | $51.00 | +$0.44 (0.9%) |
| +200 | $10,400.00 | $51.24 | +$0.68 (1.3%) |
Value at Different Prices
| Price Change | Price | Value | Gain/Loss |
|---|---|---|---|
| -30% | $35.39 | $7,962.50 | -$3,412.50 |
| -20% | $40.44 | $9,100.00 | -$2,275.00 |
| -10% | $45.50 | $10,237.50 | -$1,137.50 |
| +0% | $50.56 | $11,375.00 | +$0.00 |
| +10% | $55.61 | $12,512.50 | +$1,137.50 |
| +20% | $60.67 | $13,650.00 | +$2,275.00 |
| +30% | $65.72 | $14,787.50 | +$3,412.50 |
| +50% | $75.83 | $17,062.50 | +$5,687.50 |
Dollar-Cost Averaging
What is Average Cost?
Average cost (cost basis) is your total investment divided by total shares. It determines your break-even price and is used to calculate capital gains when you sell.
Averaging Down
Buying more shares when the price drops lowers your average cost. This can be a good strategy if you believe in the long-term value, but be careful not to throw good money after bad.
Tax Implications
Your cost basis determines capital gains taxes when you sell. You can use specific identification to sell high-cost shares first (minimizing gains) or low-cost shares (maximizing gains for tax-loss harvesting).
Frequently Asked Questions
Average Cost Formula
Average Cost = Total Investment ÷ Total Shares
Example: 100 shares @ $50 + 50 shares @ $40 = $7,000 ÷ 150 shares = $46.67/share
Dollar-Cost Averaging Benefits
- Reduces impact of volatility
- Removes emotion from investing
- Naturally buys more when prices are low
- Simple, disciplined approach
When to Average Down
Consider averaging down when:
- Your investment thesis is still valid
- The drop is market-wide, not company-specific
- You have a long time horizon
- You're not over-concentrated in one stock
Avoid averaging down on fundamentally broken companies.
Tax Lot Methods
- FIFO: First shares bought are first sold
- LIFO: Last shares bought are first sold
- Specific ID: You choose which shares to sell
- Average Cost: Uses average of all shares (mutual funds)