Aldi has been officially crowned the cheapest supermarket in the UK for an impressive fifth consecutive year, according to a major annual study. The consumer champion Which? found that shoppers could save hundreds of pounds over the course of a year by choosing the German discounter over its rivals.
A Decisive Victory for the Discounter
The research, which tracked daily prices for everyday items like milk, bread, and frozen peas across eight major chains, revealed that Aldi was the cheapest supermarket in ten out of the twelve months of 2025. Its main rival, Lidl, provided fierce competition, taking the top spot in July and October. However, over the entire year, the average monthly price difference between the two discount giants was a mere 77 pence.
In a direct comparison for December, a basket of 68 popular items cost an average of £123.60 at Aldi. Lidl was a razor-thin second at £123.70 for both members and non-members of its Lidl Plus scheme. This highlights Aldi's consistent low pricing, achieved without a loyalty card scheme.
The Battle Among the Big Four
Among the larger, traditional supermarkets, Asda emerged as the clear price leader, consistently beating Tesco, Morrisons, and Sainsbury's. This held true even when the rivals' loyalty card prices were factored in.
In December, the same 68-item shop cost £134.89 at Asda—around £11 more than Aldi. For Tesco Clubcard holders, the average was £135.84, rising to £139.12 without a card. At Sainsbury's, Nectar card holders paid £141.45, while non-members faced a bill of £143.74.
At the opposite end of the spectrum, Waitrose was the most expensive supermarket. Its December basket cost £170.46—a staggering £46.86 more than Aldi. Over the year, Waitrose was on average 35% more expensive for a smaller shop.
The Big Weekly Shop: Asda Takes the Crown
Which? also analysed a larger weekly shop of 180 items, though Aldi and Lidl were excluded from this comparison due to their smaller ranges. Here, Asda solidified its position as the cheapest non-discounter.
In December, the big shop cost £450.82 at Asda. Tesco Clubcard holders would have paid £462, and Morrisons shoppers around £466 with a loyalty discount. Sainsbury's Nectar holders faced a bill of £468.61, while Ocado's came to £498.19. Once again, Waitrose was most expensive at £529.17—£78 more than Asda.
Reena Sewraz, Which? Retail Editor, said: 'Aldi's consistent performance shows why it has been crowned the UK's cheapest supermarket for the fifth year in a row... Our analysis also shows that Asda remains a strong choice for shoppers looking for a bigger range of branded goods at lower prices.'
The findings come as households continue to feel the pinch. Although grocery price inflation eased to 4.3% in December, down from 4.7% in November, cost remains a primary concern. Aldi celebrated its title by releasing a series of 'Brag Bags' with slogans like 'Aldi. No loyalty card needed'.
Julie Ashfield, Aldi UK's Chief Commercial Officer, stated the company was 'incredibly proud' of the achievement. An Asda spokesperson highlighted their 'clear, consistent pricing, that's available to everyone', without the need for a loyalty card. Waitrose emphasised that value 'is about more than just price', pointing to its sourcing standards and customer service.
The price war continues to shape the market, with Lidl recently reporting a 10% surge in Christmas sales and Aldi a 3% rise. Industry experts suggest Lidl could soon overtake Morrisons to become the UK's fifth-largest grocer, while Aldi solidifies its fourth-place position behind the traditional 'big three'.
