Averaging Cost Calculator
Compute the weighted average cost of batched stock or fund purchases: add any number of batches, see the averaged cost and floating profit or loss.
Purchase batches
Average cost · 9.50
Cost share by batch
What is it
When you buy the same stock or fund several times at different prices, the real cost per share is the weighted average — total paid divided by total shares. Averaging down lowers it, but you should check the math: each batch shifts the average by its own weight.
Notes & fun facts
“Lower your average” sounds wise, but the second batch only helps if its weight matters. This calculator shows the exact new average the moment you add a batch, and the donut reveals which batch dominates your cost.
Origin & history
Weighted average cost has been the standard basis for Chinese broker position reports since the 2000s, replacing FIFO for individual stock positions. The same math applies to mutual funds that publish an averaged NAV cost.
Related keywords
Feedback
Found a problem with a tool or have a suggestion? Email us — we read every message.
