Flat A, 23, Belsize Avenue has an Energy Performance Rating (EPC) of E. This is based on the most recent assessment, dated 28 Aug 2009.

The property is connected to mains gas and has single glazed windows. It is heated using a boiler and radiators (mains gas).

Flat A, 23, Belsize Avenue last changed hands on 22nd March 2012, selling for £930,000. The transaction was logged as a leasehold flat by HM Land Registry.

In total it has sold 4 times since 1995.

The market for similar properties has risen by 7.6% since March 2012.

• Sold Mar 2012£930,000
• Sold Jul 2006£750,000
• Sold Feb 2004£665,000

Land Registry records and our Estate Agent network show 51 sales of comparable properties within 270 metres of Flat A, 23, Belsize Avenue since 2012.

Most recently, Flat 3, Andrew Court 2, Wedderburn Road, London, NW3 5QE, a leasehold flat, sold at £1,255,555 on the 18th February 2026.

Read more about house prices in NW3.

• Sold Feb 2026£1,255,555 | 3 Bed FlatFlat 3, Andrew Court 2, Wedderburn Road, London, NW3 5QEFlat 3, Andrew Court 2, Wedderburn Road, London, NW3 5QE
• Sold Mar 2025£1,350,000 | 3 Bed FlatFlat 3, 11, Belsize Park, London, NW3 4ESFlat 3, 11, Belsize Park, London, NW3 4ES
• Sold Feb 2025£1,346,000 | 3 Bed FlatFlat 1, 33, Belsize Crescent, London, NW3 5QYFlat 1, 33, Belsize Crescent, London, NW3 5QY
• Sold Feb 2025£1,320,000 | 3 Bed FlatFlat 2, 6, Lyndhurst Gardens, London, NW3 5NRFlat 2, 6, Lyndhurst Gardens, London, NW3 5NR
• Sold Jan 2025£1,520,000 | 3 Bed FlatFlat 5, 13, Belsize Park Gardens, London, NW3 4JGFlat 5, 13, Belsize Park Gardens, London, NW3 4JG
• Sold Oct 2024£1,269,537 | 3 Bed Flat46A, Belsize Square, London, NW3 4HN46A, Belsize Square, London, NW3 4HN
• Sold Jul 2024£1,563,290 | 3 Bed FlatFlat 5, 42, Belsize Square, London, NW3 4HNFlat 5, 42, Belsize Square, London, NW3 4HN
• Sold Apr 2024£1,200,000 | 3 Bed FlatFlat 2, 31, Belsize Avenue, London, NW3 4BLFlat 2, 31, Belsize Avenue, London, NW3 4BL
• Sold Dec 2023£1,850,000 | 3 Bed FlatFlat 2, 8, Belsize Park Gardens, London, NW3 4LDFlat 2, 8, Belsize Park Gardens, London, NW3 4LD
• Sold Sep 2023£1,337,000 | 3 Bed FlatFlat 2, 29, Belsize Park Gardens, London, NW3 4JHFlat 2, 29, Belsize Park Gardens, London, NW3 4JH
• Sold Apr 2023£1,490,000 | 3 Bed FlatFlat 4, Andrew Court 2, Wedderburn Road, London, NW3 5QEFlat 4, Andrew Court 2, Wedderburn Road, London, NW3 5QE
• Sold Jan 2023£1,420,000 | 3 Bed Flat25C , Belsize Avenue, London, NW3 4BL25C , Belsize Avenue, London, NW3 4BL
• Sold Sep 2022£1,520,000 | 3 Bed FlatFlat 1, 14, Belsize Park, London, NW3 4ESFlat 1, 14, Belsize Park, London, NW3 4ES
• Sold Dec 2021£1,350,000 | 3 Bed FlatFlat 3, 6, Lyndhurst Gardens, London, NW3 5NRFlat 3, 6, Lyndhurst Gardens, London, NW3 5NR
• Sold Nov 2019£1,465,000 | 3 Bed Flat29A, Belsize Avenue, London, NW3 4BL29A, Belsize Avenue, London, NW3 4BL
• Sold Feb 2019£1,350,000 | 3 Bed FlatApartment 8, 21, Belsize Lane, London, NW3 5ASApartment 8, 21, Belsize Lane, London, NW3 5AS
• Sold Nov 2018£1,200,000 | 3 Bed Flat7B , Belsize Park Gardens, London, NW3 4LB7B , Belsize Park Gardens, London, NW3 4LB
• Sold May 2018£1,560,000 | 3 Bed FlatFlat 1, 15, Belsize Park Gardens, London, NW3 4JGFlat 1, 15, Belsize Park Gardens, London, NW3 4JG
• Sold Sep 2016£1,700,000 | 3 Bed Flat7C , Belsize Park Gardens, London, NW3 4LB7C , Belsize Park Gardens, London, NW3 4LB
• Sold May 2012£1,125,000 | 3 Bed Flat25B, Belsize Avenue, London, NW3 4BL25B, Belsize Avenue, London, NW3 4BL

Our analysis of the public data ranks Flat A, 23, Belsize Avenue as the 62nd largest and the 53rd most expensive of the 446 addresses on Belsize Avenue, London, NW3.

Against the NW3 postcode district average, it is £103k more expensive than the typical property.

• Rosary Catholic Primary School

  400 m away
• Fitzjohn's Primary School

  600 m away
• Holy Trinity CofE Primary School, NW3

  600 m away

• The UCL Academy

  900 m away
• Haverstock School

  1.3 km away
• Harris Academy St John's Wood

  1.4 km away

• Belsize Park

  |

  400 m away
• Finchley Road

  |

  700 m away
• Hampstead Heath

  |

  700 m away

Environment Agency data suggests this area has a Very Low risk of flooding.