Live MOT records and model statistics.

Vehicle details and MOT test history come from the DVSA MOT History API when credentials are configured. The application computes findings from those records, saves a report snapshot, and lets you build a shortlist and viewing checklist.

For real registrations, model statistics come from DVSA’s anonymised MOT test data and collision involvement from DfT road safety and vehicle licensing statistics. Both describe comparable vehicles, never the individual car. The three demonstration registrations (AB19 CBB, EF20 CBB, GH18 CBB) are fictional, and so are their MOT records and model statistics. DVLA, commercial provenance providers and model-level theft data are not connected. MOT history covers the items tested on each test date; it does not describe the vehicle’s current condition.

The car’s own history.

MOT status

The latest recorded test and its expiry determine the status at the report’s snapshot date. A later failure takes precedence over an earlier pass in these records. This does not certify current legal roadworthiness.

Mileage progression

Readings are ordered by date and converted to miles where necessary. A drop of more than one mile is flagged as a potential discrepancy, allowing for unit-conversion rounding. Recording mistakes are possible; a discrepancy is not proof of tampering.

Annual mileage is the difference between the first and last available readings, divided by elapsed days and multiplied by 365.25. It is withheld if readings decrease or less than 90 days of history is available.

Recurring defects

A component at the same recorded location is flagged when it appears in two consecutive inspection cycles or at least three of the latest five. A failure followed by a retest within 14 days forms one cycle. Recurrence does not prove the defect remains unresolved.

Inspection guidance

Rules link recommendations to recurring defects, the latest recorded advisories, mileage discrepancies, or elevated model component rates. Recommendations remain traceable to the report’s evidence IDs.

The model’s broader pattern.

Model results describe a cohort of similar vehicles, not the condition of the individual car. For real registrations the cohorts come from DVSA’s anonymised MOT data (2025, cars and light vehicles, initial tests only), matched on make, model, fuel and age band. The three example cars use synthetic cohorts.

Reliability percentile

The weighted defects per test are compared with a supplied distribution of peer-model rates. A percentile of 35 means the rate is lower than 35% of that peer set. It is not a 35% probability of reliability.

Maintenance burden

The model’s weighted defects per test are divided by the equivalent peer rate. A ratio of 1.31× indicates a 31% higher weighted defect rate than the peer average. It does not estimate repair bills.

Confidence and missing data

A cohort is used only when it passes a gate: at least 1,000 tests, mapping confidence of 90% or higher, a positive peer rate, at least 10 peer models, and an update within the previous two years. Otherwise reliability and maintenance metrics are withheld rather than estimated. Confidence then follows the cohort’s sample size. These thresholds are a starting point and still need calibration.

Cohorts are matched on make, model, fuel and age band only. Further adjustment, for example for mileage or test year, is not applied yet.

Simple, adjustable running costs.

Annual fuel cost = annual miles ÷ UK mpg × 4.54609 litres per imperial gallon × price per litre. The calculator starts with the latest DESNZ weekly UK average pump price, with its date shown. The example cars carry an illustrative fuel economy; for real registrations you enter the car’s own mpg, because the MOT record does not include it. You can change every input.

If you enter annual vehicle tax, we add it to fuel costs. Tax is not looked up. Insurance, servicing, depreciation, finance and repairs are excluded. The current examples cover petrol, diesel and a non-plug-in hybrid; an EV charging calculator is not included.

Know where the data lives.

Each local report stores its input records, source and dataset versions, method version, calculation outputs and snapshot date. The stored snapshot remains the same when you reopen it.

Reports live in a SQLite database on this computer. Saved-car links and checklist progress live in this browser’s local storage. Clearing browser storage removes the shortlist and progress, but does not delete report snapshots.

Not checked in this version

Outstanding finance, write-off history, stolen status, VIN identity, ownership history and model theft exposure are unavailable. Missing checks must never be read as a clear result. Collision involvement is shown only as a model-level statistic, never as this car’s accident history. Vehicle crime near a postcode is an optional, separate lookup: it is not a theft risk for the model and not a stolen-vehicle check.

Safety recalls are an exception: DVSA returns a recall state alongside the MOT record on live lookups. “No known recalls found” is not the same as clearance, because recall data depends on manufacturer reporting — confirm any campaign with the manufacturer.