How much to budget for groceries, and how to find your own number

The right grocery budget is your own three-month average, not a figure from a table. Add up every grocery transaction from the last three months, from every store and every delivery, take out the non-food items that ride along on the receipts, and divide by three. Set the budget at that number rounded up to something you can remember, hold it for two months, and only then trim it, one step at a time. A household that starts from someone else's number spends the first three months arguing with the budget instead of reading it.

Why a number from another household doesn't work

Grocery spending depends on how many people eat at home, how many meals a week are cooked, where you live, what you eat, and which stores are near you. A published figure averages across all of that, so it describes almost nobody. A household of two that cooks most nights in an expensive city and a household of four that eats out three times a week in a cheap one can have the same monthly total for opposite reasons.

The published number also tends to be set as a goal before the household knows its own. Set below your real spending, it is over every month and teaches you that budgets fail. Set above it, it is met every month and teaches you nothing. Your own average is the only number that is both true and useful.

Find your own number from three months

1. Gather three full months of transactions from every account you buy food with: the main card, the debit card, the one used for delivery apps.
2. Pull out every grocery purchase, meaning food and drink brought home to eat. Include the supermarket, the warehouse club, the corner store, the farmers' market, and the delivery apps. Leave out restaurants and takeout; they are dining, and mixing them hides both numbers.
3. Subtract the non-food that rides along. Paper goods, cleaning supplies, toiletries, and the occasional phone charger from the warehouse club are household spending, not groceries. Estimate them from a few receipts if you did not split the transactions at the time.
4. Divide by three for the monthly average, and round up to a number you will remember.

A worked example, three months across four stores

Three months of grocery transactions come to $2,105. The receipts carried about $235 of non-food, paper goods and cleaning supplies mostly, which leaves $1,870 of food, or $623 a month. Round up: the budget is $650. For two adults that is about $325 each per month, which is the figure to compare when someone quotes a per-person number.

Two things the table shows that a single month would hide. The warehouse club run happens every other month, so month 2 looks cheap and month 3 looks expensive for no real reason. And delivery, the smallest line, is the one that swings the most, which makes it the first place to look when trimming.

Set the amount and decide what counts

Write down what the category includes before the first month runs, because the number only means something if the same things land in it every month.

• In: food and drink for the home, from any store, including delivery fees and tips on grocery delivery.
• Out: restaurants, takeout, and coffee shops, which are dining out; household supplies, which are their own category; alcohol, if you want to see it separately.
• Split the mixed receipts. A warehouse club run that is $180 of food and $60 of household goods should land as two amounts, or the grocery total drifts up by the household goods every other month; see How to split one purchase across categories.

Hold the budget at the rounded average for two full months. If it is over, something is landing in the category that does not belong, or the three months you measured were unusually cheap. Fix the filing before you fix the number.

Trim one step at a time

Once the number holds for two months, it is a baseline, and a baseline can be trimmed on purpose. Cut it by a step of about 8%, from $650 to $600, with one rule that produces the saving: one shop a week from a list, no second trip. If the new number holds for two months, cut again, to $560, with a second rule, perhaps a switch to the cheaper store for staples. Stop when a month goes over with the rule kept, because that is the household's real floor, and a fifth off the original average is about as far as most households get without changing what they eat.

Common mistakes

• Starting from a published figure. It describes an average household that does not exist, and it is wrong for yours in a direction you cannot predict.
• Measuring one month. The warehouse club, a holiday, or a stocked freezer makes one month a poor guide. Three months averages them out.
• Counting takeout as groceries. The grocery number goes up, the dining number disappears, and neither can be trimmed with the right rule.
• Leaving the household goods in. They ride along on grocery receipts and inflate the number by a tenth or more.
• Cutting before the number holds. A budget trimmed from a guess is a second guess. Two steady months first.
• Cutting by more than a step at a time. A big cut breaks in week three and takes the habit of tracking with it.

Common questions

What is a reasonable grocery budget per person? The one your own three months produce, divided by the number of people. Per-person figures from other households vary by a factor of two or three for ordinary reasons, so use yours as the baseline and compare only to your own past months.

Should the grocery budget be weekly or monthly? Keep the budget monthly so it lines up with income and the other categories, and shop weekly against a quarter of it if that helps you pace. A month with five shopping days needs the monthly figure to be honest about it, which a weekly budget hides.

Do delivery fees and tips count as groceries? Yes, when the order is groceries. They are part of what the food cost you, and leaving them out makes delivery look cheaper than the store when it is not.

How do I budget for a warehouse club run that happens every other month? Either average it into the monthly figure, as the example does, or give it its own category that carries its unspent balance forward, so the off month builds up the money the on month spends. Either way the three-month average already includes it.

Should I use a fixed number or a per-week rule? Both. The monthly number is the budget; a rule such as one shop a week from a list is how the number is met. A number without a rule is a wish, and a rule without a number cannot be checked.

How Zypper handles this

Zypper hands you the three-month average when you set the amount. Click a category's amount on the budget page and a History panel shows what you Spent last month and your Monthly average, with a chart of the last four months; click either figure, or a bar in the chart, to use it as the amount. Auto set does the same for every category at once, reading the last three months of what you actually spent, and shows a preview of each proposed amount before anything changes. A warehouse club run can be split into a groceries part and a household part, each with its own amount and category, so the grocery total stays clean, and a category that should build up between big shops can carry its balance forward with Roll over unspent budget. See Creating your budget, Auto set, and Splitting and linking transactions for the details, or get started with Zypper to see your own average.