Free Planning Tools & Calculators
Check key permitted development rules before you start your project. Each tool gives you an instant answer based on the GPDO 2015 rules for England, with clear explanations of what the result means and what to do next.
My Property Dashboard
See your planning constraints, permitted development limits, planning history, and neighbourhood approvals — all from your address. No sign-up required.
Check whether your property is in a conservation area, AONB, National Park, or Article 4 direction area — and what it means for your permitted development rights.
Extension Cost CalculatorCost 2026Get a realistic 2026 build cost estimate for your house extension. Enter your dimensions, spec level, add-ons, and location to get a cost range with a full breakdown.
Building Regulations CheckerBuilding RegsFind out if your home project needs building regulations approval. Covers extensions, loft conversions, outbuildings, electrics, boilers, windows, and more.
Extension Size CalculatorClass AFind out the maximum permitted development dimensions for your extension — rear, side, or wraparound — based on your property type and whether it’s on designated land.
Party Wall CalculatorParty Wall ActFind out whether your extension, loft conversion or outbuilding triggers the Party Wall Act 1996, and which notices you need to serve on each neighbour before work starts.
Rear Extension Depth CalculatorClass ACheck whether your rear extension falls within the Class A permitted development depth limits, qualifies for the Larger Home Extension scheme, or needs a full planning application.
Loft Volume CalculatorClass BEstimate the additional roof volume of your loft conversion and check whether it falls within the Class B permitted development limits for your house type.
45-Degree Rule CalculatorDaylightCheck whether your extension crosses the 45-degree line drawn from your neighbour’s nearest window — a key planning policy test that officers use to assess daylight impact.
Planning Fee CalculatorFees 2025Find out exactly how much your planning application will cost using the current England fee schedule, updated after the April 2025 increase.
Outbuilding & Garden Office CalculatorClass ECheck whether your shed, garden office, garage or summer house meets the Class E permitted development rules for height, boundary distance, garden coverage, and designated land.
Project Timeline EstimatorPlanningGet a realistic week-by-week timeline from first idea to completion, including design, approvals, party wall, and construction — with parallel stages shown.
Building Control Provider FinderBuilding RegsFind the local authority building control contact details for any council in England, and compare LABC with private approved inspectors.
Building Inspection ChecklistBuilding RegsTrack every mandatory building control inspection for your project. See what the inspector checks at each stage, how to prepare, and common issues to avoid — for 10 project types.