How to use the windfall allocation calculator
- Enter the amount received. Use the money you actually have in hand, such as a bonus after payroll withholding or a refund deposit.
- If you expect tax to be owed on this money, type your own estimate in Set aside for taxes. That share comes off the top before the split.
- Edit the list of uses. Each row has a name and a share, for example debt payoff, emergency fund, investing and spending. Use Add a use for more rows.
- Read the table. The shares can add up to 100% or less, and any money not yet assigned is shown so you can decide what to do with it.
Formula
Money to split = amount received - tax set aside
Amount for a use = money to split x share / 100
Not assigned = money to split - sum of the amounts for every use
Every amount is taken to whole cents. When a share does not divide evenly, the leftover cents go one at a time to the shares with the largest fractional cent, so the amounts add up to the money being split exactly.
A $10,000 bonus split four ways
You receive $10,000 and choose 40% for paying down debt, 30% for an emergency fund, 20% for investing and 10% for spending. The amounts are $4,000, $3,000, $2,000 and $1,000, which add up to the full $10,000 with nothing left unassigned.
Now suppose you also want to set aside 22% for taxes. That is an example figure for this illustration and not a tax rate. The tool takes $2,200 off the top, leaving $7,800 to split. The same shares then give $3,120, $2,340, $1,560 and $780.
Why a plan before the money arrives helps
A one-time sum is easy to spend without noticing, because it does not repeat like a paycheck. Writing the percentages down before you spend anything turns a vague intention into numbers you can check. The split also makes trade-offs visible: giving more to one use means giving less to another.
The percentages in the table are example choices. Nothing on this page says which split is right, and the best answer depends on interest rates on your debts, your savings, your goals and your taxes. Change every row to match your own situation.
What the split does not cover
The tool divides a number. It does not know your balances, the interest rate on your loans, the rules of a retirement account, or how a gift, refund, bonus or inheritance is taxed. Those rules differ by type of money and by where you live, so ask a tax professional if the amount is large.
If you want to turn a share into a longer plan, the debt payoff calculator shows how an extra payment shortens a loan, the emergency fund calculator estimates a buffer target, and the savings goal calculator tracks several goals at once.
Assumptions and limits
- The amount is the money you hold now, in dollars, after anything already withheld.
- The tax set-aside is an estimate you type. The tool does not look up or calculate any tax.
- Shares are percentages of the money left after the set-aside, and they cannot add up to more than 100%.
- Rounding is to whole cents with leftover cents handed out by largest fractional cent, never by dropping money.
Frequently asked questions
How do I split a bonus into percentages?
Enter the bonus, list each use with a share, and the table shows the dollars for each. The example uses 40, 30, 20 and 10 percent, but you can change every share and add rows.
Can the shares add up to less than 100%?
Yes. The unassigned remainder is shown separately so you can hold it for later. The shares cannot add up to more than 100%, because that would assign money you do not have.
Should I set aside money for taxes first?
That depends on the type of money and your situation, which this tool cannot judge. If you expect to owe tax, enter your own estimate and the split works on what is left.
Why do the amounts sometimes differ by a cent from a quick multiplication?
Each share is taken to whole cents and the leftover cent goes to the largest fraction. That keeps the amounts adding up exactly to the money being split instead of drifting by a penny.