An approval rate tells you what happened to a group of recorded applications. It can help you decide what to investigate. It cannot tell you whether your extension will be approved.
The useful starting point is your address, the work you want to do and the council's current policies. Then look at comparable decisions to understand what was accepted, what was refused and why.
Find the rate for your project and council
Use approval rates by council to find your area, then choose the project you are considering: for example, a single storey rear extension, a loft conversion or a side extension.
For London, you can start with the project tables for Southwark, Wandsworth, Camden or find another council.
Read the percentage alongside the number of decisions and the period covered. A rate based on a small sample can change substantially after a few decisions. We withhold percentages where the relevant sample has fewer than 8 decisions; that threshold does not make a larger sample a reliable prediction for your home.
A borough-wide average combines different projects and properties. A council receiving more straightforward applications may have a higher approval rate. The figures alone do not show that an identical extension would have a better chance across the borough boundary.
Understand what the figures count
The approval share is the number of records classified as approved, divided by the total classified as approved or refused, multiplied by 100.
| Part of the data | What it means |
|---|---|
| 2,343,419 classified decision records | The archived analysis collection across 181 council files in England. It is not a count of every application submitted in those areas. |
| Project and council sample | The subset used for the particular table. Check its decision count before comparing percentages. |
| Decisions since 2022 | Records with a recorded year from 2022 onwards. Records without a year cannot enter that dated sample. |
| Wider application search | Access to the 20.6 million application catalogue is separate from the classified records used to calculate these rates. |
Project categories are inferred from descriptions. They do not reliably separate every application for planning permission from a lawful development certificate or a prior approval application. Those routes answer different questions, so a category should not be read as a clean sample of full planning applications.
An archive review on 5 September 2026 found repeated references and missing years in the classified collection. The published record counts should not be treated as verified totals of unique applications. Source coverage varies by council, and rebuilding a page does not mean all its underlying records were collected that day.
Why withdrawn applications are excluded
An application that was withdrawn has no final approval or refusal to count in this calculation. Pending applications are also outside the decided sample.
People can withdraw for different reasons. These records do not establish how many withdrawn schemes would have been refused, so we cannot turn the published approval share into an adjusted probability of success.
Compare nearby decisions properly
Find a handful of similar applications and open the council records where a source link is available. The officer's report and decision notice usually tell you more than the outcome label alone.
Compare:
- the kind of property and whether the proposal is for a house or a flat
- the extension's position, dimensions and relationship to neighbouring windows and boundaries
- the planning route and the date of the decision
- any heritage designation or other site-specific restriction
- the reasons for refusal, or conditions attached to an approval
Selected examples on our pages help you inspect different outcomes. They are not a representative sample, and a nearby approval does not guarantee the same answer for your property.
Check which permission or consent you need
Some work can use permitted development rights, subject to limits and conditions. Other work needs an application for planning permission. A lawful development certificate and prior approval are separate routes with different purposes.
The answer depends on the property and the exact work, including any restrictions affecting the site. Use the government's guidance on when permission is required to understand the routes, then check your proposal against the relevant rules.
For a planning application, the council considers the development plan and other relevant planning considerations. An approval percentage is not the test the council applies. The government's guidance on determining planning applications explains that decision framework.
What to do next
Start with the free check for your address. It brings together nearby planning decisions and mapped constraints so you can see what needs closer attention.
If you want drawings, read what each stage includes and when you pay. The planning design fee is payable on approval. Council and any Planning Portal submission charges are separate and are paid at submission.