Reviewed 28 October 2026. Model version 2026-10-28-v1. This is a budgeting tool, not a quotation or an official recommended tariff. We do not describe the output as a statistically representative UK average.
Planning-drawing examples
For standard single-storey, two-storey, loft and new-home planning drawings, we use the project-specific ranges in the HomeOwners Alliance fee guide. Those guide examples are not offers from the practices in this directory. Their scope and tax treatment should be checked.
Percentage budgeting model
For wider appointments we use an editorial 5–15% range of construction cost, reflecting variation in published practitioner guidance. New-home projects use an 8–12% allowance; specialist heritage work uses 12–16%. Sources include Resi’s fee overview and RR Architecture’s residential guide. These are budgeting assumptions, not guaranteed market bounds.
Where a stage allowance is needed, planning is modelled at 30% of a full fee and design through detailed technical plans at 70%, following Architecture for London’s stage explanation. This is one practice’s guide, not a universal fee split. Some monetary tables on that page explicitly refer to 2018; we do not treat those figures as current market prices.
VAT and rounding
Published planning-drawing examples are shown unchanged because their VAT basis is not stated consistently. The optional tax allowance applies to the percentage model: it adds the standard 20% VAT rate to the modelled architect fee, then rounds to the nearest £50. A practice that is not VAT registered will not charge VAT. Published planning examples may use differing VAT conventions; confirm the written proposal before relying on the allowance.
What is excluded
Construction, other consultants, surveys, statutory charges, specialist reports, party wall services and expenses. No arbitrary postcode premium or complexity multiplier is added. Complex work can fall outside these ranges and requires a bespoke proposal.
We will refine the model using consented, scope-matched quote data once enough comparable observations exist, publishing sample size, date, coverage and VAT treatment. Until then, use the output to frame questions and request itemised proposals.