The retailer has moved fast to reach 50, having acquired Argos and Habitat seven months ago.
Argos will also change 60 of its standalone stores into the digital format. It allows customers to buy or reserve 20,000 products, or choose from a further 40,000 that can be ordered in store or delivered to their home.
The seventh mini-Habitat store has also opened today in Sainsbury’s Kiln Lane in Epsom, Surrey. The supermarket plans to open a further ten in the current financial year.
Sainsbury’s said that this strategy has meant that there is a "clear uplift of one to 2% on sales from Argos customers shopping for Sainsbury’s food, general merchandise and clothing products".
The Argos Digital stores based in a supermarket and open for more than a year have increased like for like sales by between 20% and 30%.
John Rogers, chief executive of Argos, told BBC Radio 4’s Today programme that the brand has "an offer for our customers that beats Amazon hands down". He pointed to its fast-track delivery and the convenience of being able to have items delivered to a store.
In a statement released this morning, Rogers said: "The opening of our 50th Argos Digital store just seven months after we acquired the company shows we are moving ahead at pace with our strategy.
"Our cutting-edge digital capability is a core strength of our business and our decision to transform 60 Argos stores by March next year moves our strategy on further.
"Over a third of the store estate will now benefit from cutting-edge digital technology that will improve the customer experience, making shopping faster and more convenient."