Food is usually the second or third largest household cost, and unlike rent or council tax, you control it week by week. That makes it the most powerful line in a weekly budget — and the one most often set by guesswork. Too tight and the budget breaks by Thursday; too loose and money that could be building savings drifts into the trolley. The method below sets the figure from evidence — your own — and keeps it current.
Quick answer: Track every food cost for two to four weeks, find your typical week, trim it by five to ten per cent, and test that figure for four weeks. Your weekly food budget should come from your receipts, not from a national average.
Why national averages are a poor guide
Published averages for UK food spending blend single people and families of five, London and the North East, scratch cooks and ready-meal households. Even the accurate ones describe a household that does not exist. Two families of the same size can differ by £40 a week for reasons that are entirely legitimate — dietary needs, working patterns, local prices. Use averages for curiosity; use your own records for budgeting.
Step 1: Gather two to four weeks of real data
For the next few weeks, record every food cost — the main shop, the top-up trips, the meal deals, the school lunch top-ups, the takeaway coffee if it stands in for breakfast. You are not changing anything yet, just measuring. Three weeks is enough for a working figure; four is better.
Step 2: Separate groceries from eating out
Keep two subtotals: food bought to prepare at home, and food bought ready to eat. They behave differently and are trimmed differently. The grocery figure is a need with flexible edges; eating out is a want, and belongs in your weekly flexible spending where it competes fairly with everything else you enjoy.
Step 3: Set the weekly figure
The 0.9 is a gentle ten per cent trim — enough to matter, small enough to hold. Illustrative example: three tracked weeks totalling £321 in groceries gives a typical week of £107; trimmed, a working budget of £96. If the trim proves too tight, adjust to 0.95 next month rather than abandoning the figure altogether.
As a rough sense-check, many UK households land somewhere around £35 to £50 per person per week for food prepared at home (illustrative, and genuinely wide — your own tracked figure always wins).
Step 4: Test it for four weeks
Run the new figure for four weeks before judging it. Week one is usually easy — the cupboards are full and motivation is high. Week three is the honest test. If you finish most weeks within a few pounds of the figure, it is right. If you are consistently £15 over, raise the budget and find the difference elsewhere; a food budget you cannot keep teaches nothing except that budgets fail.
When prices rise: adjust the figure, keep the system
Grocery prices will move while you hold this budget. When you notice the same shop costing more, do not absorb it silently into overspend and do not slash the quality of the week’s food overnight. Re-run the numbers: acknowledge the new typical week, apply the same gentle trim, and update the figure in your plan. A buffer of even £5 to £10 a week inside the food line absorbs normal volatility without a full reset.
Key takeaways
- Build the figure from two to four weeks of your own receipts, not from national averages.
- Separate groceries from eating out — they are different kinds of spending.
- Test for four weeks, adjust gently, and re-set the figure when prices genuinely move.
Keep the food figure honest, week after week
ClearWeek shows one clear weekly spending number and takes seconds to log each shop — so your food budget is measured against real weeks, not hopeful ones.