Move
Total: £62,175
- SDLT (HMRC)
- £34,500
- Estate-agent fee
- £8,325
- Survey
- £1,500
- Legal (sale + purchase)
- £2,500
- Removals
- £2,000
- Chain contingency (1.5%)
- £13,350
For homeowners in Tower Hamlets (London Borough of Tower Hamlets). Updated 2026-06-11.
Inner east London. Georgian terraces in Spitalfields and Wapping; early-Victorian terraces in Tredegar Square and Bow; substantial postwar council estates and recent high-density development in Canary Wharf (E14). Period stock tightly conservation-area controlled; side returns rare on the older listed/conservation streets.
The borough covers the E1, E1W, E2, E3, E14 postcode districts. Terraced homes here trade around £875,000 against the borough-wide £555,000 average.
In Tower Hamlets, the average home is valued at £555,000. Moving up by 60% to a £890,000 property triggers approximately £34,500 in Stamp Duty Land Tax (SDLT). By contrast, a 12 m² high-spec side return extension here costs around £82,524 all-in. Tower Hamlets has 58 conservation areas — among the most of any London borough.
Adjust the inputs to see your scenario. The page updates instantly as you adjust the inputs.
Moving is £20,349 cheaper than extending
Total: £62,175
Side return extension — high spec
Total: £82,524
An extension of this type and size could add roughly £72,150 (≈13%) to your home's value — Nationwide Building Society, October 2025.
Where moving starts costing more than the extension you selected. The chart follows your inputs above.
Up to about £1,085,000 of target price, moving is the cheaper route in Tower Hamlets; beyond that line, extending wins.
Decision speed: MHCLG householder statistics, year ending September 2025, excluding agreed extensions of time.
HMRC bands applied to a £890,000 purchase — the default Tower Hamlets trade-up.
| Price band | Rate | SDLT due |
|---|---|---|
| £0 – £125,000 | 0% | £0 |
| £125,000 – £250,000 | 2% | £2,500 |
| £250,000 – £925,000 | 5% | £32,000 |
High specification at typical size, inner London rates, all-in.
| Extension type | All-in cost | vs moving |
|---|---|---|
| Side return extension (12 m²) | £82,524 | £20,349 more than moving |
| Rear extension (single storey) (22 m²) | £124,982 | £62,807 more than moving |
| Wrap-around extension (25 m²) | £108,388 | £46,213 more than moving |
| Kitchen extension (22 m²) | £124,982 | £62,807 more than moving |
| Loft conversion (dormer) (18 m²) | £47,093 | saves £15,082 vs moving |
| Loft conversion (mansard) (30 m²) | £103,155 | £40,980 more than moving |
"An architect-designed house extension in London may cost between £3,000 and £5,000 per square metre. Elsewhere in the UK, you can expect to pay between £2,000 and £3,500 per square metre."
Nearby by average property value — useful if you're weighing a move to an adjacent price tier. A comparable trade-up in Merton would carry about £35,250 of stamp duty — £750 more than in Tower Hamlets.
Stamp Duty Land Tax is calculated from the HMRC bands in force for the 2025–26 tax year. Verify any figure against HMRC's official calculator before committing. Extension costs use inner London £/m² rates by extension type — industry-estimate midpoints, presented as approximations.