When credits are purchased in several packs at different unit prices, a weighted average uses total acquisition cost divided by total acquired credits. Averaging the displayed unit prices without considering pack size can give the wrong result. Keep the calculation tied to actual purchases and distinguish it from the service’s current advertised price.
Use totals as the starting point
Add the actual credit quantities and purchase amounts. If you include fees or currency conversion, identify them explicitly and apply the same basis consistently. Do not mix a fee-inclusive purchase with a fee-exclusive one without a note.
Keep accounting method and stock balance distinct
A weighted average is one way to understand acquisition cost. It does not describe the service’s internal balance logic or establish a tax-accounting method. Use appropriate professional guidance for formal accounting requirements.
Recalculate after a new purchase
A new pack at a different price changes the average for the combined pool under this simple model. Keep dated purchase records so the result can be reproduced. Avoid replacing historical costs with today’s price.
A practical sequence
- Add the credits actually acquired.
- Add the corresponding acquisition costs.
- Divide total cost by total credits on a consistent basis.
An example
One Starter purchase of 10 credits for $228.90 and one Growth purchase of 25 for $547.50 provide 35 credits at a combined purchase cost of $776.40. Dividing $776.40 by 35 gives about $22.18 per credit when displayed to cents. Keep the underlying totals for later calculations rather than multiplying back from the rounded display.
Questions about this topic
Can I just average $22.89 and $21.90?
No. The pack quantities differ. Add the purchase totals and divide by the combined credit quantity.
Is this a formal tax-accounting recommendation?
No. It is an arithmetic planning example; formal treatment needs appropriate guidance.
