ONS December 2026 CPI: Will UK inflation fall below 3%?

The Office for National Statistics publishes the UK Consumer Prices Index (CPI), the measure that will decide whether inflation is below 3% for December 2026. With predictions closing on 31 December 2026, households have a clear question to watch: will everyday prices be rising more slowly by the end of the year? The answer will come from the ONS’s first published December CPI figure, after the deadline.

The December inflation question at a glance

• Question: Will the UK’s December 2026 CPI 12-month rate be below 3.0%?
• Deadline: Predictions close on 31 December 2026.
• YES: The ONS first publishes a December rate below 3.0%.
• NO: The first published December rate is 3.0% or higher.
• Deciding result: The initial December figure on the ONS inflation and price indices page or its linked release.

The threshold is exact. A figure of 2.9% would qualify; a figure of 3.0% would not. The market uses the first published figure even if the ONS later revises it.

Where the latest CPI reading stands against 3%

The ONS inflation and price indices page is the public starting point for the latest UK CPI release. It provides access to inflation and price-index data, including the Consumer Prices Index. A dated current CPI rate has not been established for this forecast, so there is no reliable percentage-point gap to report between the latest reading and 3.0%.

That gap matters. If the latest 12-month rate is only slightly above 3%, relatively small changes over the remaining months could move December below the line. If it is well above 3%, a larger slowdown would be needed. A reading already below 3% would be encouraging for a YES outcome, but it would not settle a question about December.

Readers comparing releases should check both the reference month and the publication date. A release published in one month usually describes prices in an earlier month. They should also use the headline CPI 12-month rate, rather than a monthly price change or a different inflation measure. The December 2026 rate is the one that counts, however persuasive an earlier reading may look.

What CPI says about household prices

CPI tracks changes in the prices of a basket of goods and services bought by households. Its 12-month rate compares prices with the same month a year earlier. It offers a broad measure of inflation, though no single basket matches every family’s spending. That distinction helps explain what inflation data shows about household costs. A household that spends a large share of its budget on food, energy or transport may feel price changes differently from the headline rate.

A lower inflation rate does not mean that prices have fallen. If CPI moves from 4% to 2.9%, the measured basket is still more expensive than it was a year earlier; its price has simply risen at a slower pace. Prices would need to decline for the overall level to fall. Even then, some individual costs could continue rising.

This distinction matters when families plan a budget. Slower inflation can ease the rate at which bills increase, but it does not undo earlier increases. Whether a household feels better off also depends on pay, benefits, housing costs and the prices of the particular things it buys. The December result will answer a precise statistical question, not whether every household’s finances have improved.

How December could finish below the line

A YES outcome is plausible if price pressures ease enough for the December CPI 12-month rate to reach 2.9% or lower when first reported. Slower increases in goods and services would help. Changes in energy or food prices could also affect the headline figure, as could the comparison with prices in December 2025.

That year-earlier comparison is easy to miss. Inflation is a rate of change, so the December 2026 number depends on both the prices recorded then and the prices recorded a year before. Even if prices rise during autumn 2026, the 12-month inflation rate could fall if they rise more slowly than they did over the comparable earlier period.

A sequence of lower CPI readings before December would strengthen the case for YES, particularly if the slowdown appeared across several types of spending. It would still be a signal rather than a result. A fresh price increase late in the year, or a different pattern in the annual comparison, could leave December at or above 3%.

Why 3% or higher remains possible

The NO path does not require inflation to accelerate. It only requires the ONS’s initial December CPI 12-month rate to be 3.0% or higher. Inflation could slow from a higher level and still miss the threshold. Equally, a rate that dips below 3% in an earlier month could rise back to the line by December.

Household costs do not all move together. Some prices may stabilise while others keep rising quickly. Changes in energy, food and services can pull the headline rate in different directions, and their effects may not last. This makes a straight-line forecast from one monthly release fragile, especially without a confirmed latest reading and a measured gap to the threshold.

There is also a difference between a forecast and the number used to settle the question. Analysts may estimate where inflation is heading, and households may notice changes on receipts, but neither determines the result. The decisive figure is the ONS’s first published CPI 12-month rate for December 2026.

The deadline and the deciding ONS release

Predictions close on 31 December 2026, before the December CPI figure is published. The result therefore remains uncertain at the deadline. Settlement follows when the ONS first reports the December 2026 CPI 12-month inflation rate. A first figure below 3.0% means YES; 3.0% or above means NO. Any later revision leaves that settlement unchanged.

Until then, each new ONS CPI release can improve the picture without resolving it. The useful next check is the latest dated release linked from the ONS inflation page: note its reference month, record its headline CPI 12-month rate, and compare it with 3.0%. The final check is the first ONS release carrying the December 2026 figure.

Source: Office for National Statistics