Choosing a new or used car involves navigating a vast amount of information. Professional road tests, safety results, reliability data, running costs and environmental reports are all published separately, often using different scoring systems and criteria.
The challenge is not access to information, but how to evaluate it consistently and bring it together in a way that reflects real-world ownership.
The Expert Rating Index was developed to address this problem. It combines independent media reviews with safety testing, environmental data, reliability records, running costs and manufacturer warranty coverage into a structured, evidence-based scoring system.
The result is a balanced overall assessment designed to reflect long-term ownership as well as initial driving impressions.
At a glance
The Expert Rating Index combines independent media reviews with safety, environmental, reliability, running cost and warranty data.
Each category is scored separately and then weighted to produce overall ratings for both new and used cars.
Scores are updated regularly as new data becomes available.
What is an Expert Rating?
The Expert Rating is The Car Expert’s structured scoring system for new and used cars in the UK. We have been developing and refining it for more than eight years, with the current third-generation version launched in 2024 and refined further in 2025.
Every new car on sale in the UK receives a New Car Expert Rating. This rating brings together large volumes of independent data covering the factors that matter most to car buyers, including:
- Professional road test reviews
- Safety testing results
- Environmental performance
- Reliability data
- Running costs
- New car warranty information
All data comes from established UK and European sources that assess cars sold in the UK.
We convert this information into clear category scores for media reviews, safety, environmental impact, reliability, running costs and warranty. These category scores are then combined into an overall Expert Rating.
Separate ratings are produced for new and used cars, reflecting the different priorities of each type of buyer. For example, long-term reliability and ownership costs carry greater importance for used car buyers.
Each car’s results are presented in a simple report card format, with both an A–F grade and a percentage score for readers who want more detail. Further explanation of each category is provided below.
Expert Rating categories
Media Rating
In earlier versions of the Expert Rating, a car’s overall score was based entirely on media review scores. Today, this forms the Media Rating, which is now one part of the overall Expert Rating.
The Media Rating brings together individual review scores from more than 30 established UK and European automotive publications. Depending on the model, this may include as few as 10 reviews or more than 60. Some manufacturers limit media access to certain models, while others encourage broad coverage, which affects the number of reviews available.
What is an aggregated rating?
Rather than relying on a single review, we combine scores from multiple independent sources to reflect the overall consensus of professional road testers.
To do this, we use a weighted average system. This means we do not treat every review equally. For new cars, more recent reviews carry greater weight than older ones. For used cars, reviews are not weighted by age.
We also standardise the wide range of scoring systems used by different publications. A score of 7/10 may represent different levels of merit depending on the outlet. Our system converts these varied scoring scales into a consistent format before combining them into a single Media Rating.
This approach ensures the Media Rating reflects the broad professional view of a car, rather than the opinion of any one journalist or publication.
Reviews without scores
Some publications review cars without giving them a numerical score. These reviews are included in our database for readers to access, but they do not contribute to the Media Rating.
Unlike some review aggregators, we do not create artificial scores for unscored reviews or manually adjust scores up or down. In rare cases, a review may be included without its score if the editor believes it does not fairly represent the model being assessed. Final editorial responsibility for these decisions rests with The Car Expert.
Safety Rating
Our Safety Rating is based on Euro NCAP testing results. We use the full breakdown of Euro NCAP’s assessment, not just the overall star rating.
This includes detailed scores for:
- Adult occupant protection
- Child occupant protection
- Pedestrian protection
- Safety assist systems
This approach allows you to see where a car performs strongly — and where it may be weaker — depending on the type of protection that matters most to you.
Expiry and test age
Euro NCAP ratings expire after six or seven years. Testing standards are regularly updated and become more demanding over time, which means a five-star rating awarded several years ago may not reflect current safety expectations.
If a car remains on sale, it may be re-tested under the latest criteria, although this does not always happen.
We also take the age of the test into account. Because standards tighten over time, a five-star result from 2019 is not directly comparable to a five-star result from 2025.
Euro NCAP is revising its testing protocols in 2026, so we will update our safety scoring to reflect this.
Eco Rating
Our Eco Rating is currently based on official carbon dioxide (CO2) tailpipe emissions data for each model. We calculate an average across all available versions of the car, including petrol, diesel, hybrid and plug-in hybrid variants.
Electric vehicles produce zero tailpipe CO2 emissions and therefore score 100% in this category.
Plug-in hybrids officially produce very low CO2 emissions, but real-world results depend heavily on how frequently the vehicle is charged and how much driving is completed using electric power. For consistency and fairness, we use the official government test data for all vehicles.
What this rating does — and does not — measure
The Eco Rating focuses specifically on tailpipe emissions. It does not attempt to measure the full environmental impact of electricity generation, fuel production or vehicle manufacturing.
We focus on tailpipe CO2 because it is directly linked to air quality and public health, particularly in urban areas where most vehicles are used.
While exhaust gases contain pollutants other than CO2, these are broadly correlated with CO2 output under modern emissions standards, making it a reasonable indicator for comparative purposes.
Additional environmental data
Where available, we also display Green NCAP results, including air quality and energy efficiency ratings. However, as only a limited number of models are tested each year, Green NCAP data is not currently included in the calculation of the Eco Rating.
We continue to assess additional data sources to further strengthen this category over time.
Running Costs Rating
Our Running Costs Rating is based on independent data supplied by our technical partner, Clear Vehicle Data.
Using large-scale vehicle cost datasets, we calculate average running cost scores across each model range, covering the major expenses you can expect during ownership. These include:
- Fuel consumption
- CO2 emissions (which affect road tax and related charges)
- Insurance group
- Servicing, maintenance and repair costs (covering the first five years of ownership)
This provides a realistic view of how expensive a car is likely to be to run, not just how much it costs to buy.
Clear Vehicle Data also provides running-cost information to many of the UK’s leading leasing and fleet companies, ensuring the data reflects real-world commercial standards.
We apply separate calculation models for new and used cars. For used vehicles, servicing patterns and cost weightings differ to better reflect long-term ownership.
Reliability Rating
Our Reliability Rating is based on real-world repair and warranty data supplied by our commercial partner, MotorEasy.
This data comes directly from MotorEasy’s nationwide network of franchised dealers and independent garages. We analyse both the number of warranty claims made for each model and the average cost of those claims.
This approach provides insight into how frequently problems occur and how expensive they are likely to be when they do.
By focusing on actual repair records rather than owner surveys alone, the Reliability Rating reflects real ownership experience over time.
Warranty Rating
Our Warranty Rating assesses the standard manufacturer cover provided with each new car. We evaluate the length and structure of the standard manufacturer warranty, including:
- Duration (in years)
- Mileage limits
- Additional warranty cover specific to electric and hybrid components
Longer warranties generally provide greater peace of mind and can reduce financial risk, particularly during the early years of ownership.
We do not include conditional warranty extensions (such as cover that only applies if the car is serviced within a franchised dealer network), nor do we factor in optional extended warranties available at extra cost. The rating reflects the standard protection provided at no additional charge.
For models offered with petrol, diesel and hybrid powertrains, we aggregate the warranty data across all versions to produce a single model score.
By including warranty coverage as a separate category, the Expert Rating recognises that protection and support after purchase are an important part of a car’s overall value.
How the overall Expert Rating is calculated
Each category — Media, Safety, Eco, Reliability, Running Costs and Warranty — is scored independently using its own methodology.
These category scores are then combined to produce two separate overall scores:
- New Car Expert Rating
- Used Car Expert Rating
The weighting of each category differs between new and used cars to reflect different buyer priorities. For example, reliability and long-term running costs carry greater weight in used car assessments, while recent media reviews and safety performance carry greater emphasis for new cars.
The final score is presented in both percentage form and as a simplified A–F report card grade.
We do not publish the precise mathematical formula behind the weighting system. However, the principles behind it are transparent: each category contributes proportionately to reflect its importance in real-world ownership.
Why scores change over time
Expert Ratings are dynamic and may increase or decrease as new information becomes available.
This can happen for several reasons:
- New professional reviews are published
- Safety ratings are updated or expire
- Reliability and warranty data is refreshed
- Running cost data changes
- Older reviews gradually carry less weight in new car assessments
Because data is continuously updated, each model’s score reflects the most current evidence available. Percentage scores may change more frequently than headline A–F grades.
This approach ensures the Expert Rating reflects how a car performs today — not just when it was launched.
The Media Rating draws from more than 30 established UK automotive publications and national media outlets with regular motoring coverage.
We assess potential sources based on:
- Quality and depth of reviews
- Consistency of scoring
- Breadth of model coverage
- Editorial credibility
We review our media source list periodically and may add or remove publications where appropriate.
We only include UK-based websites to ensure pricing, specification and market positioning are relevant to UK buyers.
Owner reviews
We do not currently include owner-submitted reviews in the Expert Rating calculation.
While owner feedback can provide useful anecdotal insight, it often produces highly polarised results and can be difficult to verify at scale. Our methodology prioritises structured, independently verifiable data sources.
We continue to explore ways of incorporating owner data responsibly in the future.
Coverage and scope
The Expert Rating Index covers the vast majority of new cars on sale in the UK, with additional models added regularly.
Used Car Expert Ratings are also expanding, although historical data can be more limited for older models.
Where multiple versions of a model exist, we assess whether to group or separate them based on meaningful differences in engineering, performance or positioning. Electric models are always rated separately from equivalent petrol, diesel or hybrid versions.
Updates
The Expert Rating Index is updated continuously as new data becomes available.
On average, each model is refreshed approximately once per month, although high-profile vehicles may update more frequently if significant new data is published.
Licensing
Expert Rating data is available for licensing. The ratings are currently used by selected UK automotive partners under bespoke agreements.
For commercial enquiries, please contact editor@thecarexpert.co.uk
Last updated: 11 February 2026
