Cost Methodology

Our goal is to show a useful planning range without pretending an online estimate is a contractor quote.

1. Source records

Production price inputs will keep the source, publication date, geographic scope, unit and whether VAT is included. We prefer current official statistics and primary industry data, then use reputable market sources where official data does not provide the necessary detail.

2. Low, typical and high values

We store ranges rather than one false-precision number. The typical value represents a central planning assumption; low and high values are intended to show realistic variability in specification and project complexity.

3. Regional adjustments

Where there is sufficient evidence, a UK baseline can be adjusted for location. Regional coefficients must be traceable to evidence and are reviewed separately from the underlying project cost.

4. Calculators

Calculators combine the same price records used in cost guides with user inputs such as size, region and finish level. Optional kitchens, bathrooms or other project elements are added as separate components where possible.

5. Contingency

Contingency is shown separately rather than hidden inside the base estimate. Users can therefore see the estimated project cost and the additional planning buffer.

6. Updates

Every production guide will display a last-reviewed date. When a source is replaced or a model assumption changes materially, the relevant cost record is updated centrally so guides and calculators remain aligned.