Habits
How to turn a vague goal into a monthly number
Save more is not a goal, it is a mood. A goal has three parts, and the moment all three exist it converts into a single monthly figure that either fits your month or does not. That arithmetic is uncomfortable and it is the entire value of the exercise.
Ask someone what they are saving for and the answers tend to be a house, a cushion, the future. None of those can be acted on, because none of them contains a number or a date. The work of goal setting is almost entirely the work of turning a sentence into three specific pieces of information.
The three parts of a real goal
- An amount. A specific figure, even if it is a rough one. Fifteen thousand, not enough for a deposit. If you genuinely do not know the amount, finding it out is the goal for this month.
- A date. Not a season and not soon. A month and a year, because the date is what turns the amount into a rate.
- A place. Where the money sits while it waits, which follows almost entirely from the date rather than from your feelings about markets.
Miss any one and the goal stops being actionable. An amount with no date has no monthly figure. A date with no amount cannot be checked. An amount and a date with no place is how house deposits end up exposed to a market fall eleven months before completion.
Converting a goal into a monthly figure
Divide the amount by the number of months. That is the whole calculation, and for anything under about five years it is close enough that interest barely changes the answer.
Fifteen thousand in five years
- Ignoring interest entirely $250 a month
- If the account pays 2 percent a year $238 a month
- What 250 a month would actually reach at 2 percent $15,762
Arithmetic at a fixed 2 percent compounded monthly, not a forecast and not a rate anybody is offering. The gap between 250 and 238 is the point: over five years, interest is a rounding adjustment. The monthly amount does the work.
That is worth sitting with, because it inverts the way most people approach the subject. For short and medium goals, the return is nearly irrelevant and the contribution is everything. Only over decades does the growth rate begin to dominate, which is exactly the shape shown in compound interest explained.
A shorter example, since not every goal is five years away: 3,000 in eighteen months is 167 a month, near enough. Now you know whether the goal is real, and you found out in ten seconds rather than in eighteen months.
Where each goal should sit
The date decides this, and it decides it far more firmly than most people expect.
| Goal | Typical horizon | What the money needs |
|---|---|---|
| Emergency buffer | No date at all | Reachable in a day, amount cannot move |
| Car, wedding, course | 1 to 3 years | Certainty on a known date |
| House deposit | 3 to 7 years | Depends on how fixed the date is |
| Long term wealth | 10 years and beyond | Growth, low cost, and not being interrupted |
The reasoning behind that table is the subject of saving and investing are two different jobs, and the only row without a date is the buffer, which is sized in months of essential spending instead. That one is covered in how to build an emergency fund.
What to do when the number is impossible
Frequently the monthly figure comes out at 640 and there is 300 available. This is not a failure of the exercise, it is the exercise working. A goal that was never going to happen has been identified in ten minutes rather than discovered in year three.
Only four things can move, and it is worth being explicit about them because vagueness at this point is what makes goals quietly disappear.
- The amount. Often the softest of the four. Many target figures are inherited assumptions rather than researched requirements.
- The date. Moving a five year goal to seven cuts the monthly figure by nearly a third. If the date is not contractually fixed, it is negotiable.
- What comes in. Slower to change and usually the largest lever over a period of years.
- What goes out. Which requires knowing what actually goes out, the job of a spending record.
Ordering goals that compete
Most households have four or five goals at once and a single stream of money. Rather than splitting it five ways and progressing at nobody speed, the ordering used throughout this site is a sequence.
- A small starter buffer, around a thousand, which absorbs the ordinary shocks.
- Expensive debt, cleared hard, because a guaranteed 18 percent cost outranks any uncertain return.
- The buffer completed, to three to six months of essential spending.
- Everything else, which is where dated goals and long term investing run in parallel.
The reason for a sequence rather than a split is momentum. Finishing something changes behaviour in a way that inching towards five things does not, and the first two steps also remove the situations most likely to derail every later step.
Reviewing without rewriting
Once a year, or after any real change in income or household. That is often enough.
The review has two questions and neither is about markets. Is the date still true, and is the monthly figure still being paid. If both are yes, the review is finished and nothing needs to change. Reviewing more often creates the temptation to renegotiate a plan you wrote when you were thinking clearly, which is precisely the temptation a written plan exists to resist.
Common questions
How many goals should I have at once?
As many as you like on paper, and one or two receiving money. A stream of money divided five ways progresses slowly on all five, and the psychological cost of never finishing anything is the reason most goal lists are abandoned.
Should long term goals have a date if the date is decades away?
Yes, even an approximate one, because the date is what decides where the money sits. A goal thirty years out belongs somewhere quite different from one four years out, and without a date that decision never gets made.
What if my income is irregular?
Set the monthly figure at a level that survives a poor month, and treat better months as opportunities to add rather than as the baseline. A commitment sized for your best month is a commitment that breaks in your worst one.
Do I need a separate account for each goal?
Not necessarily, though it helps considerably. Money in a single pot gets spent according to whichever goal feels urgent this week, and separation is the cheapest way to stop goals borrowing from each other.
The amounts and rates on this page are illustrative arithmetic used to demonstrate a method. They are not forecasts, not offers, and take no account of your income, your obligations or the rules where you live.