Position Sizing & Weighted Average Engine

Stock Average & Break-Even Calculator

Compute your blended average cost when accumulating shares, or reverse-engineer exactly how many shares you need to buy to drag your break-even point down to a specific target.

Currency & Engine Mode
⚠️ Mathematical Impossibility: Your Target Average must be strictly between your Current Average Price and the New Market Price. You cannot average down to a price lower than what you are currently buying it for.
Current Portfolio Position
New Accumulation (The Buy Order)
Final Position Matrix
New Average Cost
0.00
Break-even adjusted
Total Shares Owned
0
Combined position
New Capital Required
0
Cost of new shares
Total Capital Deployed
0
Gross invested amount
Blended Weight Visualization Old Cost Basis New Capital Added

Legacy Position

Shares0
Price0
Invested0

New Purchase Order

Shares0
Price0
Invested0

Final Consolidated P&L

Total Shares0
Break-Even Price0
Current Market Value0
Unrealized P&L0
Required Upward Move to Break Even 0.00%

The Real-World Story: Catching the Falling Knife

"Averaging down" is one of the most common—and highly debated—strategies in trading. When a stock you own drops by 30%, you are faced with a choice: take the loss, wait for it to recover (which could take years), or buy more shares at the new, cheaper price. By buying more, you pull your Weighted Average Cost down, meaning the stock doesn't have to rally all the way back to your original purchase price for you to break even and escape the trade.

However, inexperienced traders often average down blindly. If you own 1,000 shares at ₹200, and the stock drops to ₹100, buying just 50 more shares at ₹100 does almost nothing to your average (it drops to ₹195). To pull the average down significantly, the new capital deployed must heavily outweigh the old capital. This is why averaging down can quickly concentrate too much risk into a single failing asset.

The Reverse Target Engine

This calculator features a professional Reverse-Targeting Mode. Instead of guessing how many shares to buy, you define the exit strategy first. If you are trapped at ₹150, the stock is currently at ₹100, and there is a massive technical resistance wall at ₹120, you can type "120" into the Target Goal. The engine will use algebraic reversal to tell you exactly how many shares you must buy right now to anchor your break-even point perfectly at that ₹120 exit window.