Walk through an example.
Imagine 1,000 in spendable cash, 100 in card debt, 300 in unpaid bills due before payday and 100 still allocated to savings goals. That leaves 500 in free cash. If only 400 remains in your flexible spending plan, the safe-to-spend estimate is 400.
If free cash falls to 250 while your spending plan still has 400, the estimate falls to 250. A negative result shows a shortfall; the calculator does not hide it by rounding up to zero.
What the number cannot know.
Use one currency for every input. Enter only cash that is spendable now; do not include expected future income or reserved goal savings. Subtract only the savings allocations you still intend to make, so money already moved out is not counted twice.
The calculator uses the same two-limit principle as Plumb, with totals you supply. It does not reconstruct category history, determine bill due dates, convert currencies or check your accounts. Unrecorded spending and stale balances can change the result.
Why is safe-to-spend different from my balance?
Your recorded balance can include money needed for bills, card debt or savings allocations. The estimate also checks how much remains in your flexible spending plan, so the smaller of those two limits may be below your balance. If a number looks wrong, check recent purchases, transfers and account balances, then open Show the math in Plumb.
Keep the explanation close to the number.
In Plumb, record income and expenses, set up your plan and open “Show the math” on Home. It explains what is included in your wallet’s estimate. Read the expense-tracking guide or learn about manual budgeting.
Free to download. Optional in-app subscriptions.