How to Use the Cost Averaging Down Calculator
Averaging down means buying more shares of a stock you already hold after its price has dropped, lowering your overall average cost. Enter your current shares and average cost, plus the additional shares and the percentage change versus your existing average, and this tool instantly calculates your new cost basis and the cash required.
Since averaging down typically happens after a price drop, you'll usually enter a negative value for the change rate — for example, enter -20 if you're buying 20% below your existing average. Check whether the resulting new cost basis is meaningfully lower and whether you can actually afford the additional cash required before committing.
Keep in mind that averaging down works very differently depending on why the price fell. If it's a temporary market pullback, lowering your cost basis can pay off — but if the company's fundamentals have genuinely deteriorated, adding more shares can deepen your losses, so weigh the decision carefully.
Frequently Asked Questions
Buying more shares at a price below your existing average pulls the total cost divided by total shares down. Conversely, buying at a price above your existing average actually raises your cost basis.
No. If the price drop reflects a real deterioration in the company's fundamentals rather than a temporary pullback, averaging down can deepen your losses. Check the reason behind the decline before deciding.
Yes. The rate reflects how far the new buy price differs from your existing average, so in the typical averaging-down scenario (a price drop), just enter a negative (-) value.