The answer to which supermarket is cheapest can change before your next weekly shop. A low-priced basics basket at one retailer may cost more once you add branded cereal, nappies, a delivery slot or fuel for the journey. The practical way to spend less is to compare the products you actually buy, then choose the shop that gives your household the lowest final total.

For many UK shoppers, Aldi and Lidl are often the starting point for the cheapest groceries. Their limited ranges, own-brand focus and fewer costly promotions help keep shelf prices low. But they are not automatically the lowest-cost choice for every basket, every week or every postcode.

Which supermarket is cheapest for a full basket?

There is no single supermarket that wins every comparison. The cheapest option depends on what is in your trolley, whether you buy own-brand or branded products, and whether you can use offers without buying things you did not plan to purchase.

Discounters usually perform well on everyday staples: milk, bread, fruit, vegetables, pasta, tinned goods, frozen food and household basics. If most of your shop is straightforward own-brand food, Aldi or Lidl may offer the lowest bill. Their trade-off is range. You may not find a particular dietary product, branded item, specialist ingredient or preferred size, which can lead to a second shop elsewhere.

Among the larger supermarkets, Asda is often competitive for a broad family shop, especially when your list includes branded goods alongside own-brand essentials. Tesco, Sainsbury’s and Morrisons can be close on selected items, but the final price can depend heavily on loyalty pricing, multibuys and temporary promotions. Waitrose and M&S generally sit at a higher price point, although a small number of their products can be good value when quality, portion size or a specific offer matters to you.

That is why a headline comparison based on a small basket is useful but incomplete. A supermarket can be cheapest for 20 popular items and still be more expensive for your regular shop.

Compare the basket, not the supermarket name

The strongest saving comes from comparing a repeatable list. Start with the 15 to 30 products you buy most weeks: breakfast items, packed-lunch food, evening meals, cleaning supplies, toiletries and anything your household uses regularly.

Check like for like wherever possible. Compare the same brand, size and flavour, or compare equivalent own-brand products by price per 100g, per litre or per wash. A £1.20 pack is not cheaper than a £1.35 pack if it contains far less product. Unit pricing is one of the quickest ways to spot a misleading saving.

Then look at the whole cost of buying that basket. Include delivery charges, minimum spends, carrier bag charges and the cost of travelling to the store. A supermarket that is £3 cheaper can stop being cheaper if it requires a long car journey or an expensive delivery slot. For drivers, combining a food shop with lower-cost fuel can make a meaningful difference over a month.

PricePAL Compare helps make this check quicker by letting shoppers compare grocery prices and scan barcodes while planning or shopping. Rather than relying on a store’s reputation for being cheap, you can check the price of the item in your hand and decide whether to buy, swap or leave it.

Own-brand swaps usually matter more than one offer

It is easy to spend time chasing a 50p promotion while overlooking the larger difference between a branded product and a comparable own-brand alternative. Swapping several regular lines can cut more from a weekly bill than visiting a second supermarket for one special offer.

This does not mean choosing the cheapest version of everything. Some households have firm preferences, allergies, dietary needs or products where the branded option genuinely lasts longer. Keep those items in your basket, but challenge the products where the label matters less: chopped tomatoes, rice, pasta, cleaning spray, bin bags and many frozen vegetables are sensible places to test a cheaper alternative.

A useful rule is to switch one or two products at a time. If your household likes the replacement, make it your new default. Repeat that process each week and the savings become routine rather than a one-off effort.

Why loyalty prices need a second look

Loyalty schemes can lower the cost of a shop, particularly if you already use the supermarket regularly. But they should not decide where you shop on their own. A loyalty price may be good value, yet the non-member price is often used to make the saving appear larger than it is.

Before adding an offer to your trolley, ask three questions. Is it cheaper than the equivalent product elsewhere? Would you buy it at its normal price? Will you use all of it before it goes off? If the answer is no, it is not a saving.

Multibuys deserve the same scrutiny. Two packs for £4 only beats one pack for £2.20 if you need two packs. Buying extra food because of a deal raises your spend now and can increase waste later. The cheapest weekly shop is the one that covers your needs without filling cupboards with bargain items you will not use.

The hidden costs that change the cheapest choice

Convenience has a price, and it is worth measuring it honestly. Smaller convenience branches are useful for top-up shops, but their prices can be higher than the same supermarket’s larger store. Use them for forgotten milk or an urgent ingredient, not as the default place for a full weekly shop when budget is tight.

Online shopping can be cheaper for some households because it reduces impulse purchases and makes totals visible before checkout. It can also cost more when delivery fees, substitutions and minimum-spend top-ups are added. Booking a lower-cost slot and saving a standard basket can keep online shopping under control.

Food waste is another hidden cost. A large pack may have the lowest unit price, but not if half of it ends up in the bin. Smaller households may save more by buying a slightly dearer pack in the right quantity. Families may do better with larger packs, provided they can portion and freeze what they will not use straight away.

Finally, do not separate groceries from travel costs. If one supermarket is a few pence cheaper on food but another is on your normal route and has cheaper petrol or diesel nearby, the second option may leave you better off overall. Your total household spending matters more than winning a price comparison on one shelf.

A simple way to find your cheapest supermarket this week

Set aside ten minutes before you shop. Write your essentials list, including the exact products that drive your bill. Compare prices for those lines, not just advertised offers. Choose the store with the lowest total after travel or delivery costs, then keep an eye on substitutions and impulse buys once you are there.

It also helps to separate a planned main shop from occasional top-ups. Buy most of your essentials where your basket is cheapest, then only use another retailer when a specific product or genuine deal makes the extra trip worthwhile. This protects your time as well as your money.

Prices and offers move constantly, so repeat the check when your normal basket changes or when you notice the bill creeping up. The supermarket with the cheapest reputation is useful to know; the supermarket with the cheapest version of your own weekly shop is the one that helps you save money every week.