Sales across the wider group – including its Castorama and Brico Depot chains in France – were also badly hit by lockdowns in place across Europe, with total sales down by a quarter in the three months to April 30.
Sales have begun to improve since the phased reopening of stores in the UK and France in the second half of April, with UK and Ireland sales surging 18.9% in the first week of May.
Kingfisher said 288 of its 289 B&Q stores are now open in the UK and Ireland, while its 683-strong Screwfix arm is operating on a click-and-collect basis only.
Shares in Kingfisher lifted 5% after the update.
Chief executive Thierry Garnier said: “Having initially closed our stores in France and the UK, we have rapidly adapted how we operate to meet the essential needs of our customers safely during lockdown.
“We started by transforming our operations to meet a material increase in online transactions through our click-and-collect and home delivery services.
“We reconfigured our retail space and processes, allowing a phased and safe reopening of stores whilst preserving the social distancing and other health and safety protocols that are likely to be with us for some time.”