The price of Diesel rose by 5.4% and Petrol increased by 4.8% in the month of September 2026 and were up by 22% and 14% respectively since September 2025.
This was the largest annual increase in the price of Diesel since November 2022 when prices increased by 24.7%. It is the largest annual increase in petrol prices since May 2024 when prices rose by 14.5% when compared with May 2023.
The price of Home Heating Oil rose by 7.2% in the month between August 2026 and September 2026 and was up by 58.6% in the 12 months to September 2026.
The Consumer Price Index (CPI) increased by 4.1% in the 12 months to September 2026 and was up by 0.2% since August 2026.
Home Heating Oil contributed 0.45 percentage points towards the overall inflation rate in September 2026 while Diesel contributed 0.34 percentage points and Petrol 0.26 percentage points.
In September 2026, Petrol was at its highest price levels since August 2022 while Diesel was at its highest level since April 2026, which was the highest price level seen since July 2022.
The Price Index for Home Heating Oil was at its highest level since April 2026, which was the highest level since the CSO started publishing detailed price sub-indices in November 1996.
The National Average Price in September 2026 for Diesel was €2.06 per litre while Petrol was €1.96 per litre.
Figure 1 shows the annual percentage change in the prices of Diesel, Petrol, and Home Heating Oil since 2019.
Figure 2 shows the price indices for Diesel, Petrol, and Home Heating Oil since 2019. These indices show the respective price level compared with the base period December 2023 = 100 and are used to show price trends over time.
Figure 3 details the National Average Price for Diesel and Petrol. The CSO does not publish a National Average Price for Home Heating Oil.
Figure 1 shows that the price of Home Heating Oil increased by 58.6% in September 2026 when compared with September 2025. This is the largest increase in the price of Home Heating Oil since April 2026 when the price increased by 80.4% year on year. The increase in April 2026 resulted in the highest price level for Home Heating Oil since the CSO started publishing detailed price sub-indices in November 1996.
The largest annual increase in the price of Home Heating Oil was seen in March 2022 when prices increased by 126.6% in the year. However, due to the low price of Home Heating Oil in March 2021, the overall price level was not as high as we saw in April 2026.
Diesel has seen its largest year on year price increase (22%) since April 2026, and is the second highest year on year increase since November 2022. This price increase has resulted in the month of September 2026 being the third highest National Average Price per litre (€2.06) for Diesel. Only June 2022 (€2.09) and July 2022 (€2.07) had higher average prices for Diesel.
Petrol has seen its largest year on year price increase (22%) since July 2024 and is at its highest National Average Price (€1.96) since July 2022 when the National Average Price per litre for Petrol was (€2.08). The highest recorded National Average Price for Petrol was in June 2022 when a litre of petrol cost €2.15.
Figure 4 details the annual percentage point (pp) contributions of Diesel, Petrol, and Home Heating Oil. This is each items impact on the overall rate of inflation.
Figure 4 shows that Home Heating Oil contributed 0.45pp towards the overall inflation rate of 4.1% for September 2026. This compares with a 0.35pp contribution in August 2026 and is the highest percentage point contribution towards inflation since April 2026 when it contributed 0.63pp towards an overall inflation rate of 3.7%. March 2022 was the month where Home Heating Oil had the largest impact on inflation with a contribution of 1.11pp.
Diesel contributed 0.34 percentage points towards inflation in September 2026, while petrol contributed 0.26pp. This is the highest percentage point contribution for Petrol since September 2022 when it contributed 0.29pp towards inflation. It is the highest percentage point contribution for Diesel since April 2024 when Diesel contributed 0.42pp to the overall inflation rate of 3.7%.
In total, Fuel and Home Heating Oil contributed 0.9 percentage points to the overall inflation rate in September 2026. The overall inflation rate increased by 4.1% in September, up from a rate of 3.7% in August 2026.
Prices for Home Heating Oil are collected on a specific pricing day every month centrally by staff in the CSO offices. This day is the second Tuesday of the reference month and is the same every month regardless of the actual date. Inquiries are carried out by phone or by internet. The CSO survey 26 oil suppliers from around the country and ask for the price of 1000L of oil on the pricing day. This supplier's price is compared with their price for 1000L the previous month and a relative price change for the supplier is calculated for both Kerosene and Gas Oil. For both oil types, the average percentage change of all the suppliers is calculated.
To calculate the final percentage change of Home Heating Oil, a weighting factor is applied to both the Kerosene and Gas Oil percentage changes based on information from the CSO’s Household Environmental Behaviours - Energy Use 2024 release.
Prices for Diesel and Petrol for September are collected from the second Tuesday until the third Tuesday of the month. Prices for Diesel and Petrol for September 2026 were collected during the period 07 September to 15 September inclusive. Around 100 prices from petrol stations are collected by 30 Consumer Price Index pricers around the country. These pricers collect the displayed price for a litre of both diesel and petrol. A National Average Price (NAP) is calculated for both Diesel and Petrol using a standard mean of all the prices collected during the month. This average price is compared to the average price from the previous month and the relative monthly change for Diesel and Petrol is calculated.
To calculate the percentage change in the CPI between two periods of time
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Statistician's Comment
The Central Statistics Office (CSO) has today (08 October 2026) published a release focusing on the prices of diesel, petrol and home heating oil in Ireland for September 2026 as part of our Insight Series. This is the second release in this series focusing on fuel and home heating oil.
Commenting on the release, Anthony Dawson, Statistician in the Prices Division, said: “This Insight Series release focuses on the price developments of Diesel, Petrol, and Home Heating Oil in Ireland since 2019. This is a more detailed look at data from the Consumer Price Index (CPI) for September 2026, which has also been published today. In the month of September 2026, we saw significant price movements for Fuel and Home Heating Oil.
Diesel and Petrol increased by 5.4% and 4.8% respectively in September 2026 while Home Heating Oil prices rose by 7.2% when compared with prices in August 2026. Overall, the CPI increased by 0.2% in the same time period.
When comparing September 2026 with September 2025, Diesel rose by 22%, Petrol 14%, and Home Heating Oil prices were up by 58.6%.
Overall, the CPI increased by 4.1% in the 12 months to September 2026. In terms of percentage point (pp) contributions, Home Heating Oil contributed 0.45pp towards the overall inflation rate in September 2026. Diesel contributed 0.34pp towards inflation, while Petrol contributed 0.26pp. In August 2026, Home Heating Oil contributed 0.35pp towards inflation, Diesel 0.23pp and Petrol 0.16pp.
When we look at the price indices which show price trends over time, in September 2026 the price of Diesel was at its highest level since April 2026, which was the highest level seen since July 2022 while the price of Petrol was at its highest level since August 2022. Home Heating Oil was at its highest level since April 2026, which was the highest price level since the CSO started publishing detailed sub-indices almost 30 years ago in November 1996.
Users should note that prices for September were collected during the period 07 September to 15 September inclusive. Prices may have increased or decreased between then and the end of September. Further information on the methodology for Fuel and Home Heating Oil can be found below under Methodology section”