The HCI found that overall UK household costs rose 3.9% in the year to June 2025, an increase from 2.7% in the year to March 2025.

However, costs for low-income households rose by 4.1%, ONS said, compared with 3.8% for high-income households in the year to June 2025.

The findings have prompted the Royal Statistical Society to call for more regular HCIs and for the studies to be given the same prominence as CPI to better influence policymaking.

The HCI found that from May 2025, low-income households have experienced a higher annual rate of inflation for the first time since June 2023.

Private renter households had the highest annual inflation rate of 4.5% in June 2025, reflecting rising private rental payments, followed by social and other renter households, which had a 4.4% inflation rate in the year to June 2025.

In contrast, owner occupiers experienced the lowest annual inflation rate of all tenure types, at 3.4%, while households with a mortgage had the next lowest at 4%.

Non-retired households had a higher annual rate of inflation of 4% in June 2025 than retired households ( 3.8%), while the annual inflation rate for households with children rose from 2.8% in the year to March 2025 to 4% in the year to June 2025; for households without children, it increased from 2.6% to 3.9% over the same period.

The HCI is not part of the ONS’s official statistics, and are currently in development, with instalments released on quarterly basis.

Commenting on the HCI, the Royal Statistical Society said that between June 2021 and June 2025, low-income households experienced cumulative inflation of 29.2% compared with CPI inflation of 24.8%.

The Royal Statistical Society added that the ONS should move towards accreditation for HCIs and to produce them monthly, making them equivalent in status to CPI.

Sarah Cumbers, chief executive of the Royal Statistical Society, said: “Once again the Household Costs Indices illustrate that CPI and CPIH do not fully capture how households experience inflation.

“It is important that MPs and policy-makers make use of HCIs to better understand the impact of inflation – especially on low-income households.”