How the maths works
How to use it
- List every expense that arrives once or twice a year: car registration, insurance premiums, holiday gifts, annual subscriptions, vehicle maintenance, school costs, pet vaccinations.
- Enter the full annual cost of each, not the monthly share — the calculator divides.
- Move the resulting monthly figure to a separate account on payday, automatically.
A worked example
Car registration $180, holiday gifts $600, car maintenance $480, subscriptions $200 and an insurance premium $240 total $1,700 a year — $142 a month. None of those five are surprises. They only feel like emergencies because nothing was set aside, and each one lands on a credit card at 22% APR instead.
Where this sits in the Financial Literacy resource
A calculator tells you where you are. It does not tell you what to do next, and a number without a plan behind it tends to produce anxiety rather than progress. These stages are free, need no account, and cover the decision this calculator is measuring.
Common questions
What is a Life Just Happened Fund?
Money set aside every month for the things you know are coming but that do not arrive monthly. It is not an emergency fund — an emergency fund covers what you cannot predict, this covers what you can. Keeping them apart is what stops the registration renewal from eating the cushion you were saving for a real emergency.
Is this the same as a sinking fund?
Yes. "Sinking fund" is the textbook name, borrowed from corporate finance where it means money a company sets aside to retire a bond. It describes the mechanism accurately and tells you nothing about why you would want one. We call it a Life Just Happened Fund because that is when you reach for it — the tyre, the vet, the school trip, the December that arrives every single year and surprises everybody anyway.
Where should I keep the money?
In its own account, labelled for the purpose, separate from both checking and your emergency fund. The label matters more than it sounds: money in an account called "Life Just Happened" gets spent on exactly that, and money sitting in checking gets spent on whatever happens next.
How is this different from just budgeting?
A monthly budget only sees monthly bills, so an annual $600 expense is invisible for eleven months and then breaks the budget in the twelfth. This converts it into a $50 monthly line your budget can actually see and plan around.
What this calculator is not
It is an educational model, not a projection and certainly not advice. It knows nothing about your income, your state, your debts or your benefits status, and it ignores taxes and fees unless the page says otherwise. If you receive SSI or SSDI some of this maths works differently and getting it wrong can cost you eligibility — start with the Disability Wealth Guide instead. Our sourcing and correction policy is on the editorial standards page.
Nothing here is stored. Every calculation runs in your browser. No numbers are transmitted, logged or saved to any server, and no account is required. Close the tab and it is gone.