What is the real-world MPG of a Infiniti M?
Owners report an average of 33.3 mpg across all Infiniti M engines with data, about 91% of the official combined figure. The engine tables on this page give the figure for each engine and generation.
Infiniti M MPG: what owners actually get
Owners report 33.3 mpg from a Infiniti M, about 91% of the official figure. On its NEDC-tested engines that is 91%, better than typical: the median NEDC-tested car in this 8,216-engine dataset returns 82%. The tables below give the figure for every engine and generation we hold. Add your own at the bottom and the averages get better for the next buyer.
33.3mpg
Real-world average, all engines
91%
of the official combined figure
28–40
Range reported by owners (mpg)
25
Owner submissions
Found an Infiniti M for sale?
Paste the advert and we read it against the Infiniti M’s known faults, its MOT history and the DVLA record, with the real-world 33.3 mpg from this page in the running-cost line, and tell you what the seller has not. Free, about a minute, no card.
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Infiniti M
| Engine | Official (NEDC) | Official (WLTP) | Real MPG | % of official | Owners report |
|---|---|---|---|---|---|
| M30d | 37.7 | – | 33.2 | 88% | – |
| M35h | 40.9 | – | 34.3 | 84% | 30.0–39.0 |
| M37 | 27.7 | – | 27.7 | 100% | – |
All figures in miles per gallon (UK). “Owners report” is the spread of individual submissions for that engine.
Add your Infiniti M Real MPG
What does yours actually do? Read it off the trip computer over a full tank or work it out from litres and miles. No postcode, no sign-up. The more people add, the better the averages get, and this page stays free.
Infiniti M fuel economy questions
Why is the Infiniti M real MPG lower than the official figure?
Official figures come from a laboratory test cycle, not the road. Cold starts, short trips, hills, load, tyres and driving style all cost fuel the test does not see. A gap of 10 to 30 per cent is normal; a much bigger gap on one engine usually points at a fault, a heavy right foot, or a diesel that never gets warm.
Where did the Honest John Infiniti M Real MPG page go?
The site closed in August 2026 and its Real MPG section went with it. This page is where the Infiniti M figures now live: rebuilt from the archived dataset, with the official figures kept alongside, and reopened for new submissions.
Looking at an Infiniti M right now? Check the advert before you go and see it.
Where the Infiniti M figures come from
If you used the Honest John Real MPG section before the site closed in 2026, this is where the Infiniti M figures now live. The owner-reported averages above were rebuilt from the archived dataset (archived page, 2026-03) alongside the official NEDC and WLTP figures and new submissions from CarAdCheck readers, and the section is open so they keep improving. Real-world figures also feed the running-cost estimate in our free advert check.
CarAdCheck is not affiliated with Honest John or Volkswagen Financial Services. How we rebuilt Real MPG.
Other Infiniti models
Before you go and see it
Fuel economy is one line on the Infiniti M running-cost sheet. These guides cover the checks that stop you buying the wrong one.
How to haggle for a used car: negotiate the price with what its records showHPI check vs carVertical: which is better, and our pick for a UK carMOT advisories explained: how to check them, and which ones should worry you
All buyer's guides →