The 2021 Honda Civic Sport uses regular unleaded gasoline with an octane rating of 87.
Gasoline requirements for the Civic Sport
The Civic Sport, powered by Honda’s 2.0-liter i-VTEC engine in the 2021 lineup, is designed to run on regular unleaded fuel. Honda’s owner’s manual specifies a minimum octane rating of 87 (regular) and allows higher-octane fuels if you choose to use them. In everyday driving, 87 octane is recommended and sufficient to prevent knocking on the 2.0L engine.
Fuel blends and octane notes
In the United States, regular unleaded gasoline typically carries an octane rating of 87. The Civic’s engine is tuned for regular gasoline, and regular octane (87) or higher is acceptable. The manual also indicates the vehicle can run on gasoline containing up to 10% ethanol (E10). Avoid higher-ethanol blends such as E15 or E85 unless the manual explicitly approves them for this model year and trim.
Practical guidance for owners
For everyday driving, simply use standard regular unleaded gasoline. If you frequently operate the vehicle under heavy load or in conditions that might cause knocking, you may experiment with higher-octane fuel, but note that the official recommendation remains regular 87 octane. Always follow the manual’s fuel guidelines and use fuel from reputable stations.
Summary
Bottom line: For a 2021 Honda Civic Sport, regular unleaded gasoline at 87 octane is suitable. You may use higher-octane fuels if desired, but they are not required for this engine. The Civic Sport also accepts standard ethanol blends such as E10.