The difference between 50 ppm and 500 ppm diesel is the sulphur content, measured in parts per million. 50 ppm diesel (0.005% sulphur) is a lower-sulphur, cleaner-burning fuel, while 500 ppm diesel (0.05% sulphur) has a higher sulphur content. Many newer diesel engines are designed for 50 ppm, but you should follow your vehicle manufacturer fuel specification rather than assume. Sulphur content is not the same as the cetane rating, which measures ignition quality. Diesel is not regulated at the pump: effective 1 July 2026, the 50 ppm wholesale price is 2517.170 c/l (R25.17) at the Gauteng benchmark and 2429.97 c/l (R24.30) at the coastal benchmark, and 500 ppm is 2478.77 c/l (R24.79) inland and 2391.57 c/l (R23.92) coastal. Retail diesel prices vary by station.
This guide is part of our South African Fuel Prices hub.
What ppm means
“ppm” stands for parts per million and refers to the amount of sulphur in the diesel. 50 ppm diesel contains 0.005% sulphur and 500 ppm diesel contains 0.05% sulphur, so 50 ppm is the lower-sulphur, cleaner-burning grade.
Sulphur content is not the same as cetane
The ppm figure describes sulphur content, which mainly affects emissions and how cleanly the fuel burns. It is different from the cetane rating, which measures how readily the diesel ignites. A lower sulphur figure does not by itself mean better fuel economy or a higher cetane number.
Which engines use which grade
Many modern diesel engines, especially common-rail engines and those fitted with a diesel particulate filter, are designed for low-sulphur 50 ppm diesel, and using a higher-sulphur fuel can damage them over time. Some older diesel engines and certain agricultural or industrial equipment can use 500 ppm. This is not a universal rule, so always follow your vehicle manufacturer fuel specification.
The price difference (example using prices effective from 1 July 2026)
The regulated wholesale list price for 50 ppm diesel is slightly higher than for 500 ppm. Effective 1 July 2026, Gauteng benchmark wholesale prices are 2517.170 c/l for 50 ppm and 2478.77 c/l for 500 ppm. Because the retail diesel price is not regulated, the price you pay at the pump varies by station — see our current petrol and diesel prices guide.
Frequently asked questions
What is the difference between 50 ppm and 500 ppm diesel?
The difference is the sulphur content. 50 ppm diesel (0.005% sulphur) is a lower-sulphur, cleaner-burning fuel, while 500 ppm diesel (0.05% sulphur) has a higher sulphur content. Both are sold in South Africa.
Which diesel grade should I use?
Follow your vehicle manufacturer fuel specification. Many newer diesel engines, especially those with particulate filters, are designed for 50 ppm, while some older engines can use 500 ppm. Do not assume a grade without checking your manual.
Does 50 ppm diesel give better fuel economy?
Not necessarily. Sulphur content mainly affects emissions and engine cleanliness, not fuel economy on its own, and it is not the same as the cetane rating that measures ignition quality. Use the grade your manufacturer specifies.
Is the diesel price regulated in South Africa?
No. Only a wholesale list price is regulated. Each service station sets its own retail diesel price, so pump prices vary. Effective 1 July 2026 the 50 ppm wholesale price is 2517.170 c/l at the Gauteng benchmark and 2429.97 c/l at the coastal benchmark.
Official sources
- Department of Mineral and Petroleum Resources (DMPR): fuel prices
- DMPR media statement: fuel prices effective 1 July 2026
- Fuels Industry Association of South Africa: current and past fuel prices
Verification and sources
Verification note: This guide was independently fact-checked against official support documentation. Learn more about our Editorial Policy & Financial Review Board and how our corporate finance team ensures accuracy and safety for South African consumers.