Duration.

Horizon-based budgeting

Know what your money is for — and where it ought to sit.

Duration is a budgeting app for money that doesn't all sit in one account. Every amount gets a purpose and a time horizon, and the horizon decides where it is held — as cash, in a low-risk fund, in shares. Duration keeps the plan and the accounts in step.

Register interest Read the concept →
Horizon ↓ when you'll need it
Buckets → what it's for
Out-of-pocket Debit account
GroceriesBillsTransportEveryday
Short-term Low-risk fund
Home maintenanceInsuranceTrip to Japan
Medium-term Mixed fund
Car replacementRenovation
Long-term Equities
Pension top-upChildren's fund
The horizon decides the vehicle Buckets hold the purpose

If you budget with envelopes and keep your savings invested, you already know the gap.

Getting spending under control is the hard part, and there are good tools that help you do it. But they stay mostly silent on where the money then sits — anything you've invested tends to fall out of the budget and into "tracking accounts", off to one side.

And where it sits matters. Money you'll need in a year belongs somewhere different from money you'll need in three years, or five — cash, a low-risk fund, shares, matched to when you'll spend it. Duration keeps that decision in the same picture as the budget, instead of in your head, on a fund platform, or in a spreadsheet.

The app

Every purpose, under the horizon that holds it.

Buckets is where the second axis lives: what each amount is for, grouped by when you'll need it. Nothing here is stored — every figure is derived from the ledger, as of the day you're reading it.

The Buckets view: eight buckets grouped under four horizons, each with its status, a goal bar where one is set, and columns for this cycle's activity, the amount allocated, and the balance.
Buckets · a worked example Amounts read in your own currency and conventions

Spotlight · getting the data in

Transactions arrive on their own.

Connect an account and each transaction comes in as it lands — nothing typed, nothing exported by hand. CSV covers anything a feed can't reach, invested accounts included.

The part that matters is what happens next. Duration matches what arrives against what is already in the ledger, holds back the duplicates rather than quietly doubling a figure, and tells you whether the account ties out. Sort them when you have time — an unsorted transaction is honest about being unsorted.

Spotlight · drift

See the plan and the accounts side by side.

Allocated is what you've promised each horizon; funded is what the accounts actually hold. The difference is drift. On payday you might assign 2,000 to short-term while it is still sitting in your debit account — short-term reads 2,000 under, out-of-pocket 2,000 over, and one transfer closes both.

A worked tier ladder · drift = allocated − funded
Horizon Held in Allocated Funded Drift
Out-of-pocket Debit account 10,000 12,000 −2,000
Short-term Low-risk fund 40,000 38,000 +2,000
Medium-term Mixed fund 80,000 80,000 —
Long-term Equities 200,000 200,000 —

Spotlight · goals

Goals that match how you actually save.

A goal is two decisions. When: a date, or a recurring anchor — the 25th of every month, a weekday, a yearly date. What: contribute a sum, or hold a balance. Four combinations, no tangle of target types — enough for the sinking funds you top up each month and the one-offs you save toward by a date.

And spending from a bucket never erases what you saved toward it — a drawdown is the goal doing its job, not backsliding.

Spotlight · traceability

Every number traces back.

Duration stores no balances. Every figure is derived from a journal of postings, as of any date you ask — so the numbers cannot quietly disagree with the record. Corrections keep the original date, deletions are recoverable, and the whole ledger is searchable and yours to export.

Also

Shared costs, separate budgets
Split expenses with a partner without merging books. Who owes whom is held as claims, not cash — each of you sees your own share, and the two sides always reconcile.
Any currency, any country
A book is kept in its own accounting currency, and amounts and dates read in your own conventions. Duration assumes no home market.

Stated plainly

  • No optimiser

    Duration records your decisions and shows you their consequences. It will not move your money for you, or tell you that now is the moment to act.

  • Friction on purpose

    Deciding where money goes is the one part worth doing by hand — it is where the judgement lives. The tool is here to inform that, not to automate it away.

Register interest

Being built now, in earnest.

Duration is in active development, and will open to others once it does what it promises — no sooner. If the picture above is one you recognise, leave your address and you will hear when there is something worth trying.

No newsletter and no marketing lists — just the occasional note when there is real news about Duration. Your address is used for nothing else, and you can ask to be removed at any time.