Free planning check
Will your project needplanning permission?
A straight answer in about two minutes. Your likely planning route, the constraints that matter, the council fee and what to do next, built on the national permitted development rules.
What can you build at your address?
Step 1 of 5 · Your address
We use your postcode to find your local planning authority. Nothing is stored.
Checked against the GPDO 2015 (SI 2015/596, as amended), GOV.UK permitted development guidance, the national planning fee schedule from April 2026 and the ONS postcode directory via postcodes.io. General guidance, not a formal determination.
How it works
Four steps to a straight answer
Tell us the address
Your postcode finds your local planning authority, so the fees, policies and decision periods in your report are the right ones for your council.
Describe the project
Pick the project type and answer a handful of plain-English questions about the property and its designations. The checker applies the national permitted development rules to your answers.
Read your result
Your likely route, permitted development, prior approval or a planning application, why, what it costs, how long it takes and the sensible next step.
Get your online assessment
Leave your details and we come back with a written assessment of your property, with the planning route and the next step set out clearly.
Example results
What your result looks like, project by project
Five worked examples on illustrative addresses across our four counties, including the honest answers, not just the green ones. Your own result is built live from your own answers.
Single-storey rear extension
Prior approval5m rear extension on a 1930s semi, Harpenden
A 5m projection is over the 3m automatic limit for an attached house, but within the 6m prior approval allowance. The council notifies the neighbours and has 42 days to respond.
- Council fee £249, decided within 42 days, deemed consent if the council misses the deadline
- Not available in conservation areas or on listed buildings, which is why the checker asks
- Party wall notices due to both neighbours two months before starting
- Building Regulations apply in full
Illustrative. Run the checker for your own address.
Side return extension
Planning requiredSide return on a Victorian villa in a St Albans conservation area
Side extensions are not permitted development on designated land, so in a conservation area the honest answer is a planning application, designed to the conservation area guidance from day one.
- Council fee £548, eight-week target decision
- Materials, brick bond and joinery detail carry real weight with conservation officers
- Conservation coverage is extensive across St Albans, Harpenden and the North London villages
- A heritage statement is usually expected with the application
Illustrative. Run the checker for your own address.
New build home
Full planningOne new dwelling on a paddock plot near Wheathampstead
New dwellings always need full planning, there is no permitted development route to a new house. On a green belt plot the case turns on the site's planning history and the narrow exceptions national policy allows.
- Council fee £610 for a single dwelling, eight-week target decision
- Green belt policy limits new homes to village infill, replacement dwellings and previously developed land
- Biodiversity net gain of 10% applies to new dwellings
- CIL is chargeable in most districts, and the self-build exemption must be filed before work starts
Illustrative. Run the checker for your own address.
Loft conversion
Permitted developmentHip-to-gable with rear dormer on a detached house, Radlett
A hip-to-gable plus dormer on a detached house typically adds under the 50 cubic metre allowance, stays behind the front roof plane and below the ridge, so no planning application is needed.
- A Lawful Development Certificate at £274 formally confirms it, and helps when you sell
- Side-facing windows must be obscure glazed, openable parts at least 1.7m above floor level
- Not permitted development in conservation areas, the checker tests for this
- Building Regulations apply in full, including fire escape provisions
Illustrative. Run the checker for your own address.
Garden annexe
Talk to us firstSelf-contained annexe for a parent, Amersham
A garden room used as a home office or gym is usually permitted development. The moment it becomes self-contained living accommodation it stops being incidental and normally needs a planning application, or careful design to stay within an ancillary use.
- Height limits apply: 2.5m within 2m of a boundary, otherwise up to 4m with a dual-pitched roof
- Must sit behind the principal elevation and cover under half the garden
- Councils look at kitchens, bathrooms and separate access when judging independence
- A route we design regularly, and the use class question is worth settling before you spend
Illustrative. Run the checker for your own address.
What it covers
Included in every result
- Permitted development eligibility for your project and property type under the GPDO 2015
- Whether the prior approval route applies, with its 42-day decision
- What a conservation area designation changes for your specific project
- Listed building status and what it means for consent
- Green belt policy, which shapes most new build and rebuild cases across our four counties
- Article 4 directions, where a council has withdrawn permitted development rights
- Flood zone implications where they apply
- The correct national application fee and statutory decision period for your route
- A plain-English explanation of the rules applied, and your sensible next step
Being honest
What it can't do
- It can't measure your house. Where a dimension decides the route, it tells you the limit that matters
- It isn't a legal determination. Only a Lawful Development Certificate or a planning decision is
- It doesn't predict a planning committee. It tells you the route and the policy tests that apply
- Scotland, Wales and Northern Ireland run separate planning systems, so results there are indicative only
Where an answer genuinely depends on a survey or the council’s judgement, the result says “talk to us first” rather than guessing. That honesty is the point of the tool.
Fees and timescales
Planning fees in England, from 1 April 2026
These fees are set nationally, they do not vary between councils. If someone quotes you a different figure for one of these standard applications, query it.
| Application type | Fee | Decision period |
|---|---|---|
| Householder planning application (extension, alteration) | £548 | 8 weeks |
| Lawful Development Certificate (proposed, householder) | £274 | 8 weeks |
| Full planning, single new dwelling | £610 | 8 weeks |
| Prior approval, larger rear extension | £249 | 42 days |
| Householder curtilage works (outbuilding, wall, fence) | £272 | 8 weeks |
| Discharge of conditions, householder | £89 | 8 weeks |
| Non-material amendment, householder | £46 | 28 days |
Correct as of 1 April 2026. Fees index each April with the previous September’s CPI. The clock starts when the council validates your application, not when you submit it. Design fees for drawings, the planning agent, structural engineering and council liaison are separate, and are defined during your Feasibility Study.
The alternatives
Four ways to find out, compared
| This check | Call your council | Planning Portal | Paid pre-app | |
|---|---|---|---|---|
| Cost | Free | Free | Free | £200 to £500 |
| Time to an answer | About 2 minutes | 2 to 4 weeks | Self-service | 4 to 6 weeks |
| Specific to your address | Sometimes | |||
| Explains conservation area rules | ||||
| Explains green belt policy | Sometimes | |||
| Covers Article 4 directions | Sometimes | |||
| Written record | ||||
| Legally binding | Indicative only |
The only legally binding answer is a Lawful Development Certificate or a planning decision. Everything else, including this check and a paid pre-application, is guidance. This check gets you to the right route in minutes, so any money you do spend is spent on the right application.
Frequently asked
Answered without the sales pitch
Often not. Most modest single-storey rear extensions fall under permitted development if they stay within the national size limits. You will need a planning application if the house is listed, if permitted development rights have been removed by an Article 4 direction, if the extension goes to the side in a conservation area, or if it exceeds the GPDO 2015 limits. The checker on this page applies those rules to your answers.
Where we work
Built for our four counties
The checker works for any address in England. Our design and build work, and our working knowledge of the local planning authorities, spans Hertfordshire, Buckinghamshire, Bedfordshire and North London.
Hertfordshire
St Albans · Harpenden · Radlett · Berkhamsted · Tring · Wheathampstead
Projects in this areaBuckinghamshire
Amersham · Beaconsfield · Chalfont St Giles · Chalfont St Peter · Gerrards Cross · Chesham
Projects in this areaBedfordshire
Woburn · Ampthill · Flitwick · Leighton Buzzard · Dunstable · Shefford
Projects in this areaNorth London
Hampstead · Highgate · Totteridge · Mill Hill · Finchley · Muswell Hill
Projects in this areaWhen the checker isn't enough
Cases that always need a professional first
The checker gives the right answer for the routine majority of residential projects. These cases need a design and planning team involved before money is spent.
- Grade I and Grade II* listed buildings, and substantial works to any listed building
- New dwellings and replacements in the green belt, where the policy case decides everything
- Basement excavations and structurally ambitious remodels
- Sites with unresolved access, covenants or land assembly questions
- Anything likely to trigger an Environmental Impact Assessment
- Projects where the budget question comes first, start with the Project Calculator
Next step
Got your route? Now get the numbers
A Feasibility Study turns your planning route into a costed, programmed and risk-assessed plan you can actually build from.