What this tool is for
The worksheet is a prompt to separate past investment from a choice about the future. It does not know your values or predict outcomes. It simply asks what each option costs and returns from today forward.
How to use it
Enter only costs you would still have to pay and benefits you could still receive. Do not include money already spent, time already invested, or effort that cannot be recovered. Then estimate the best realistic alternative, including any switching cost or opportunity cost.
Examples of sunk costs
A subscription already paid for, a degree partly completed, a project with months of work behind it, or a losing investment can all create pressure to continue. The past can explain why a decision feels difficult, but it cannot change which option has more value from this point on.
Use judgment, not just arithmetic
Some benefits cannot be reduced to money. Add notes about uncertainty, reversibility, relationships, health, and learning. A small difference in a spreadsheet is not a command; it is a reason to examine the assumptions before deciding.
A useful final question
If you had not already spent anything, which option would you choose today? That question will not answer every case, but it often exposes whether a past investment is carrying more weight than a future benefit.