Free tool · Australia

Sinking fund calculator

Enter six numbers about your building and see whether its sinking fund is on track — the year it runs short, and the contribution that would keep it solvent. No login, no email. It runs the same engine behind Plinth.

Your building

Six numbers. Everything recomputes as you type.

We build a starter register from your building’s age, type and size, then project the fund 15 years. Indicative only — a real plan uses your actual register.

Underfunded

On the current levy, the fund runs short in 2040.

Recommended levy

$63,000

$3k above current

Runs short

2040

fund goes negative

15-yr works

$1.3m

escalated to 2040

Lowest balance

−$3k

in 2040

Reserve balance — 2026 to 2040

Your fund, year by year, against the safety floor.

−$34k$115k$264k$413k$562kSafety floor $50kRuns short 2040Now'27'29'31'33'35'37'39'40

This is the same engine behind Plinth — refine it with your real register on a live plan.

How the calculator works

Most “sinking fund calculators” just compound a savings target. This one models the building. From the age, type and size you enter, it assembles a realistic starter register of the capital items a building like yours has — roof and waterproofing, façade, lifts, fire systems, switchboard and the rest — and places each one in its lifecycle, so an older building shows works coming due sooner.

It then projects the fund 15 years: each work escalated to the dollars of the year it falls due, the balance drawn down as works happen and topped up by your levy and interest. The verdict and the recommended levy come from keeping that balance above a safety floor in every year — not from a flat percentage rule.

It’s a fast, honest first read, not a statutory plan. To turn it into a living plan you update as works are done — with documents, renewals and quotes that feed back into the forecast — see the forecasting software or open a live plan.

Questions

Is this sinking fund calculator free?
Yes — it's free and needs no login. Enter your building's basics and it projects the fund 15 years and shows the levy needed to keep it solvent.
How accurate is it?
It's an indicative first read. It builds a starter asset register from your building's age, type and size, then runs Plinth's real forecasting engine. A formal plan uses your building's actual register, genuine quotes and a condition assessment.
What is the recommended levy figure?
It's the flat annual contribution that would keep your fund above its safety floor across the whole 15-year projection — the levy that avoids a shortfall and a special levy down the track.
Does it work for NSW, VIC and QLD?
Yes. The maths is the same wherever you are — only the name changes (capital works fund in NSW, maintenance fund in VIC, sinking fund in QLD). The calculator models the fund regardless of the label your state uses.