Comprehensive Guide
Learn more in our Personal Finance Guide.
How it works
A multi-goal sinking fund plan answers the question single-pot calculators cannot: with one limited monthly surplus and several named targets, how should each dollar split, and when does everything actually land? This planner runs a rolling allocation rather than a static percentage split. The near-term goal — travel here, due in twelve months — takes its mathematically exact payment off the top ($262 on defaults); the remaining $438 divides across the other pots pro-rata by target size, so the $12,000 emergency top-up outpaces the $9,000 car fund. Then the part that matters happens dynamically: whenever any pot reaches its target, its monthly deposit rolls forward to the next open goal, accelerating everything behind it. The simulation tracks all three pots compounding at your APY simultaneously and reports completion months, total interest earned (~$590 on these defaults) and the milestone table. The insight most planners miss is that equal-percentage splits are rarely optimal — hard deadlines deserve exact funding while flexible goals can absorb leftovers, and letting completed pots roll their deposits forward shaves months off the final finish compared with splitting evenly forever. Re-run after any change in surplus, because allocation shares shift non-linearly as deadlines and balances interact.Formula
Near-term payment = target × r ÷ ((1+r)^D − 1) | Remainder splits pro-rata by target | Completed pots roll their deposit into the next open goal
Tips
- Give only genuinely dated goals hard deadlines; let flexible ones absorb the rolling extras.
- Re-check allocation after every raise — surplus changes move completion months non-linearly.
- Keep pots in labelled buckets of one high-yield account rather than separate banks.
- If a deadline forces an unaffordable payment, extend the date before shrinking other goals.
- Audit pots quarterly; balances drift from reality as purchases happen mid-cycle.