How to reduce your grocery bill in four weeks: a step-by-step plan

You cannot tell whether the plan is working without a starting figure. Look back over the last four weeks of bank or card statements and add up everything spent on food and household groceries, including top-up shops, corner shop trips and food deliveries. Divide by four to get your weekly baseline.

Write it down somewhere you will see it. Your target for the end of the month is to bring that figure down, and the tracker at the end of this guide shows how to measure it.

Keep every receipt this week, or use your supermarket app's order history. At the end of the week, sort the spending into rough groups:

Also check your cupboards, fridge and freezer and write down what is already there. That list becomes the starting point for next week's meals.

This week, shop with a plan rather than browsing.

Now go through your most-bought items and find a cheaper version of each.

• Drop one brand level. Move from premium to standard own-brand, or from standard to the value range. Try one swap per item; if you do not like it, go back. Most people keep the majority of swaps.
• Compare unit prices. The price per kilo, litre or 100 sheets on the shelf label is what matters. Bigger packs are usually cheaper per unit but not always, and multibuys only help if you would use everything.
• Use loyalty prices. At Tesco and Sainsbury's, member prices cut the cost of a typical basket by about 3% in Which?'s September 2026 comparison, so always scan the card.
• Try frozen and tinned. Frozen vegetables, fruit and fish are often cheaper per portion and do not go off.
• Consider a discounter. In the same Which? comparison, Aldi's basket was about 15% cheaper than Tesco with Clubcard. Even moving part of your shop helps.

Food thrown away is money thrown away. This week, focus on using everything you buy:

• Store food properly: most fruit and vegetables last longer in the fridge, and bread freezes well.
• Understand dates: "use by" is about safety and should be followed; "best before" is about quality, and food is usually fine after it.
• Keep a "use first" shelf in the fridge for things that need eating soon.
• Batch cook and freeze portions of anything you will not get through.
• Use reduced-price "yellow sticker" items only if they fit your plan or can be frozen the same day.

Apps that sell surplus food cheaply can also help; see our guide to reducing food waste for more ideas.

Fill in a simple tracker each week:

At the end of the month, set your new weekly food budget in the budget planner. Then move the difference into savings on the same day each week, or it will quietly be spent elsewhere. The savings goal calculator shows what that weekly amount adds up to, and SYM can prompt you to put it aside.

If you are struggling to afford food, check whether you qualify for help such as Healthy Start (for pregnant women and families with young children on certain benefits), free school meals and holiday activities and food programmes run by local councils. Our guide to free help with food costs lists the main schemes, and Citizens Advice can refer you to a food bank if you need one urgently.