Stocks
Stock Average Calculator
Blend two lots into a volume-weighted average price.
How the calculation works
The tool computes a volume-weighted average price across two lots: total dollars spent divided by total shares. That average is the break-even price before additional fees if you treated both lots as one position.
Formula & example
Average = (shares₁×price₁ + shares₂×price₂) ÷ (shares₁ + shares₂)
100 @ $40 and 50 @ $36 → average = $5,800 ÷ 150 ≈ $38.67.
Why use this calculator
Mental averages drift when lot sizes differ. Weighting by shares prevents treating a small cheap add as equal to a large expensive lot.
When to use it
Use when you received multiple fills or bought in two tranches and need a single average cost for planning exits.
Tips for accurate results
- For more than two lots, chain averages or sum all cost/shares.
- Tax lots may differ from average cost.
FAQ
Is average cost the same as tax cost basis?
Not always. Brokers may use specific identification or other methods. This is an educational average-cost view.