Most people can tell you their salary to the pound and their rent to the pound, and then stop. Between those two numbers sits somewhere between a third and a half of everything they earn, and it is genuinely unaccounted for. Not wasted, necessarily. Unaccounted for.
This lesson fixes that, and it does it with the only method that works: thirty days of writing things down.
There is no shortcut here and I am not going to pretend otherwise. Every budgeting tool you have ever opened asked you to estimate your spending, and the estimate is the part that is wrong. You cannot budget from a number you guessed.
Why the national average is not your answer
Start with what the country spends, because it is useful for exactly one thing and misleading for everything else.
The Office for National Statistics published its family spending figures on 11 June 2026, covering April 2024 to March 2025. Average weekly household expenditure was £676.60. That is £2,931.93 a month, or £35,183.20 a year.
| What | A week | A month | Share |
|---|---|---|---|
| Housing (net), fuel and power | £118.40 | £513.07 | 18% |
| Transport | £96.40 | £417.73 | 14% |
| Everything else, combined | £461.80 | £2,001.13 | 68% |
| Total | £676.60 | £2,931.93 | 100% |
Housing and transport are the two largest categories and the ONS says so plainly. Together they come to £214.80 a week, or 31.7% of spending.
Which leaves 68% of the average household’s money inside a single row labelled “everything else”. That row is the subject of this lesson. It is also why the average is no use to you: it is an average of millions of households, none of which is yours, and its largest component is a bucket.
What the exercise is
For thirty days, every time money leaves your account, you write down three things: the amount, the date, and which of seven categories it belongs to.
That is the whole method. It takes about forty seconds a day.
The seven categories are the ones MoneyHelper uses in its budget planner, and I recommend them over inventing your own because they have already been tested on a very large number of people. MoneyHelper is the free and impartial service run by the Money and Pensions Service, an arm’s length body of government.
- Income. What comes in, after tax.
- Household bills. Rent or mortgage, council tax, energy, water, broadband, phone.
- Living costs. Food, toiletries, cleaning, anything consumed.
- Finance and insurance. Loan and card repayments, insurance premiums, savings transfers.
- Family and friends. Childcare, gifts, birthdays, anything spent on other people.
- Travel. Fuel, tickets, parking, car tax and servicing.
- Leisure. Eating out, subscriptions, hobbies, holidays, everything you chose.
Three rules make the difference between an exercise that works and one you abandon in week two.
Write it down the same day. Not at the weekend. Memory of small spending decays within hours, and the small spending is the entire point.
Do not judge anything while you record it. You are a person taking a measurement. If you start editing your behaviour in week one, you have measured a month that does not exist.
Record the annual bills at one twelfth. The £240 car insurance that landed in March belongs in this month at £20, not at zero. Otherwise every month you measure is wrong by the size of whatever happened not to fall in it.
One thing the exercise cannot do is hold prices still while you measure. The ONS put CPI at 2.9% in the 12 months to July 2026, which means a month measured today is already slightly out of date by the time you finish adding it up. That is an argument for repeating the exercise once a year, not for skipping it.
A worked month
Here is one month recorded properly, for a single person taking home £2,200. The figures are illustrative. The shape is what matters.
| Category | Recorded | Share of income |
|---|---|---|
| Household bills | £1,010.00 | 45.9% |
| Living costs | £312.40 | 14.2% |
| Finance and insurance | £268.00 | 12.2% |
| Leisure | £287.15 | 13.1% |
| Travel | £164.60 | 7.5% |
| Family and friends | £62.00 | 2.8% |
| Total out | £2,104.15 | 95.6% |
| Left | £95.85 | 4.4% |
Now the part the exercise is actually for.
Before tracking, this person would have told you their leisure spending was “maybe a hundred and fifty a month”. It was £287.15. Not because of one extravagant evening, but because £287.15 arrived as a coffee, a lunch, two subscriptions, a round of drinks, a takeaway and a pair of trainers, and no single one of those felt like a decision.
That is the general finding, and it is the reason the method is thirty days of writing rather than one evening of estimating. The categories people misjudge are always the ones made of small frequent amounts, and they misjudge them downwards.
What to do on day 31
Add each column. Then ask three questions, in this order.
Is the total more than my income? If it is, that is the finding, and it outranks everything else on the page. Nothing else in this course matters until that line is the other way round.
Which category surprised me? There will be one. It is usually leisure or living costs, and it is usually out by half or more. That category is where a change has the most effect for the least effort, because you were not choosing it deliberately in the first place.
When did I last check my fixed costs? Household bills were 45.9% of income in the month above, and housing is the largest category in the national figures too. Nobody enjoys ringing a broadband provider. It is still worth more per hour than anything you will do to your coffee habit.
The counterweight
Tracking does not create money, and I want to be honest that for a great many households the finding will be that the sums do not work at any level of care.
The FCA’s Financial Lives survey, whose 2024 findings were released in May 2025, found that one in ten UK adults have no cash savings at all and a further 21% have less than £1,000. One in four have low financial resilience, meaning they have missed payments, are struggling to keep up with commitments, or have nothing to fall back on. Among those who did hold cash savings, the median amount was £5,000.
Those are not people who failed to track. A month of measurement tells you where you stand; it does not by itself change where you stand. What it changes is that every later decision in this course gets made on your figures instead of on a guess, and that is worth forty seconds a day.
Summary box
- Tracking beats estimating, because the categories people get wrong are made of small frequent amounts and they always guess low.
- Record amount, date and category on the same day, for thirty days, without editing your behaviour while you measure.
- Use seven categories: income, household bills, living costs, finance and insurance, family and friends, travel, leisure.
- Spread annual bills at one twelfth so no month is distorted by what happened to land in it.
- On day 31 ask three questions: is the total above my income, which category surprised me, and when did I last check my fixed costs.
- National averages are context, not a target. Average weekly household spending is £676.60, but 68% of it sits in a category labelled “everything else”.
Frequently asked questions
How long does the exercise actually take each day? About forty seconds, if you do it the same day. It takes far longer if you leave it to the weekend, because you then have to reconstruct the week from a bank statement.
Can I use my banking app’s categories instead? You can, and it is better than nothing, but check its work. Bank categorisation misfiles supermarkets that also sell fuel, and it cannot know whether a transfer was savings or spending.
What if my income varies? Track for thirty days anyway, then repeat in a month that looks different. Two months of real figures tell you your range, which is more useful to a variable earner than any single average.
Should I count savings as spending? Put savings transfers in finance and insurance, so they show up as money that left. You want the picture of what is committed, not a flattering one.
Updated on 11 September 2026.
Sources
- ONS, family spending in the UK, April 2024 to March 2025, released 11 June 2026
- FCA, Financial Lives 2024 survey, findings released May 2025
- MoneyHelper, budget planner, Money and Pensions Service
- ONS, consumer price inflation, published 19 August 2026
Fluid Academy teaches money skills. It does not give personal financial advice.…