Is this calculator a real quote?

No. It produces an indicative range based on Q1 2026 broker-submission data. To bind cover you need an FCA-authorised intermediary. InsuranceDico is not FCA-authorised and cannot place cover.

Why do estimates vary so widely?

The low-to-high spread (typically 2.1×) reflects underwriter appetite differences across the UK market. Two insurers can quote the same risk at very different prices on the same day.

Where do the multipliers come from?

From the InsuranceDico Q1 2026 broker submission survey (n = 8 UK underwriters), BIBA member-firm data, and ABI commercial-lines rating notes. Full sources are on the methodology page.

CAR · COMPREHENSIVE VS THIRD PARTY CALCULATOR

4-step

UK premium estimator, methodology published

Comprehensive vs Third Party Insurance Cost Calculator UK (2026)

InsuranceDico

Car

Comprehensive vs Third Party Insurance Cost Calculator UK (2026)

Reviewed by Emma Walsh, Cert CII·Updated 10 April 2026

View formula & sources

1Business type

2Employees

3Turnover

4Claims history

What kind of business is it?

Trade and construction profiles are loaded with a higher base rate to reflect physical-risk exposure.

INSIGHT

Base rate × headcount × turnover × trade loading × claims loading. Multipliers are sourced from InsuranceDico's Q1 2026 broker submission survey (n = 8 underwriters) and republished quarterly. Inputs are not stored or shared.

Cite this tool

InsuranceDico (2026). Comprehensive vs Third Party Insurance Cost Calculator UK. Retrieved from /car-insurance/comprehensive-vs-third-party/calculator

What this tool does: returns a range and the inputs that produced it so you can challenge a broker's number. It is not a quote. InsuranceDico is not FCA-authorised and cannot place cover.

#methodology

How we calculate comprehensive vs third party insurance cost

Every estimate on this page is built from a base rate of £95 multiplied by four factors: headcount, turnover band, trade risk loading, and claims history. The high estimate is the low estimate multiplied by a 2.10× broker market spread. Multipliers are sourced from our Q1 2026 broker submission survey (n = 8 UK underwriters), BIBA member-firm data, ABI commercial-lines rating notes, and FCA value-measures filings.

We publish the formula so any broker or accountant can audit our numbers. If a UK underwriter's number diverges from this range by more than 25%, ask them to itemise which factors they weight differently.

Full methodology & sources ⬇ Download methodology

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  width="100%" height="900"
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Emma Walsh

Cert CII · Dip PFS

Motor & Consumer Editor

Consumer insurance specialist. Emma maintains our motor and comparison methodology.

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