A goal without a date and a number is a wish. The whole method below is converting one into the other, and then automating it so willpower is not involved.
Sizing a goal in four lines
The arithmetic is deliberately simple. Complexity is where good intentions go to die.
- 1Write the goal as a thing, not a feeling. "A 10% deposit on a $300,000 flat" beats "buy a place".
- 2Write the total cost, including the parts people forget: fees, tax, moving, furniture.
- 3Write the date. A real month and year, not "in a couple of years".
- 4Divide the total by the number of months. That is the monthly figure, and it is either possible or it is not.
If the number is impossible, the goal is wrong
That is useful information, not failure. Move the date, reduce the target, or accept it is not this decade’s goal. What does not work is keeping an impossible number and feeling bad monthly.
Where the money should sit
The single decision that matters is horizon. Not appetite, not what someone at work is doing — how long until you spend it.
| Time until you need it | Where it belongs | Why |
|---|---|---|
| Under 1 year | Instant-access savings | Certainty beats return over this distance. |
| 1 to 3 years | Savings, possibly a notice account | A market fall here would not have time to recover. |
| 3 to 5 years | Mostly savings | Recovery is possible but not assured. Do not gamble a deposit. |
| 5 to 10 years | A cautious or balanced portfolio | Long enough that inflation becomes the bigger risk than volatility. |
| 10 years or more | A growth portfolio | Time to absorb falls, and inflation to outrun. |
The house deposit rule
Money for a deposit you plan to use within a few years does not belong in the market. People who ignore this and are unlucky lose the house, not just the percentage.
When goals compete
Most people have several goals and not enough money for all of them at once. Ranking them honestly beats funding all of them badly.
- Sequential
- Fund one at a time, in order. Fastest to a visible result, which matters for motivation more than people admit.
- Weighted
- Split the monthly amount by priority. Slower on each, but nothing stalls entirely.
- Deadline-driven
- Fund whatever has the nearest immovable date. The right approach when a date is genuinely fixed.
Some goals are really one goal
A wedding, a honeymoon and a first home are often the same eighteen months. Treat them as one total with one date and the arithmetic stops lying to you.
When you fall behind
- 1Look at why. A one-off cost is different from a monthly figure that was never realistic.
- 2Do not raid the emergency fund. That is a different pot with a different job.
- 3Move the date before you abandon the goal. A goal reached later still counts.
- 4Reduce the transfer rather than stopping it. Stopping is much harder to reverse than reducing.
- 5Re-run the four lines. A goal set two years ago may not be the right one now.
Documents you may also need
Financial Planning
Working out what your money is for, in the right order: an emergency fund first, then the goals with dates on them, then the long horizon.
Financial PlanningYour Emergency Fund
How much to hold, where to keep it, how to build it when money is tight, and what actually counts as an emergency.
Financial PlanningTax-Efficient Saving
Using the allowances you already have, in the right order, before reaching for anything complicated — and why the tax tail should not wag the dog.
This document was last updated on 1 August 2026. We publish the current version here at all times; superseded versions are available on request.
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