Free tool · No signup · Updated August 11, 2026
Sinking Fund Calculator
The bills that wreck budgets aren’t emergencies — they’re the ones you knew were coming and never funded. Add yours below and the calculator gives you the single monthly number your budget has been missing.
Runs entirely in your browser — nothing you type is sent anywhere
| Expense | Total $ | Months away | Saved $ | Repeats | Per month |
|---|
Why the two numbers differ
Set aside every month is your catch-up figure: it divides what’s still owed on each item by the months you have left before it lands. It’s higher, because you’re starting late on some items — almost everyone is.
Steady state is what the same list costs once every fund has run a full cycle: annual items become one-twelfth of their cost per month, and one-off items drop off the list for good. That’s your real long-run number, and it’s the one to build your budget around.
If the catch-up number is uncomfortable, that’s information, not failure. It’s the size of the hole you’ve been falling into every year — usually on a credit card, at 24% APR.
What belongs in a sinking fund
Anything predictable that doesn’t arrive monthly. The test is simple: would this surprise you if it happened, or only if it happened this month? Only the first kind is an emergency.
- Vehicle — registration, insurance if paid in instalments, tyres, brakes, the annual service
- Home — property tax, HOA dues, boiler service, and a standing repairs fund (a rough rule: 1% of the home’s value a year)
- Health — dental work, glasses, the deductible you reset every January, the vet
- Annual subscriptions — the ones that renew at full price while you remember the promo price
- Occasions — Christmas, birthdays, weddings you already know about, travel home
Keep them in one savings account and track the balances in a sheet — you do not need five bank accounts, you need the amounts written down somewhere you’ll actually look.
LedgerLens Zero-Based Budget Toolkit
This page gives you the number. The toolkit is where the balances live between now and the due date.
- Sinking funds tracker — every fund, its target, its balance, and the monthly contribution
- Zero-based budget sheet with a live “left to assign” figure
- Debt payoff planner — snowball and avalanche side by side
- Net worth tracker and a budgeting-app break-even calculator
- Excel/Google Sheets, real formulas, yours forever — no subscription
Instant download link on your receipt. This is our own product, not an affiliate offer.
Related tools and reading
- Emergency Fund Calculator — how many months you actually need, from your risk factors
- Debt Snowball vs Avalanche Calculator — free, no signup
- Best Budgeting Apps 2026 — six apps, prices verified from official pages
- YNAB vs Monarch 2026 — the head-to-head, with 3-year cost math