Extend vs Move House London 2025: Cost Comparison & Guide
Should you extend your home or move? Complete cost comparison including 2025 stamp duty changes, hidden moving costs, extension ROI, and decision framework.
Quick Answer
For most London homeowners, extending is cheaper than moving. Moving costs £36k-50k+ (stamp duty £21k + fees). A quality extension costs £40k-60k but adds space without relocation stress or 2025 stamp duty increases.
£36k-£50k+
Moving Cost
£40k-£60k
Extension Cost
£21k avg
Stamp Duty
Check your specific property constraints
Free Property CheckThe True Cost of Moving House in London (2025)
The average London property price is £543,370. After April 2025 stamp duty changes, moving became significantly more expensive.
2025 Stamp Duty Changes
| Threshold | Before April 2025 | After April 2025 |
|---|---|---|
| First-time buyer | £425,000 | £300,000 |
| Home mover | £250,000 | £125,000 |
Complete Moving Costs Breakdown
| Cost Item | £543k Property | £750k Property |
|---|---|---|
| Stamp duty (2025 rates) | £21,650 | £32,500 |
| Estate agent fees (1.5%) | £8,150 | £11,250 |
| Solicitor fees (both sides) | £3,000-6,000 | £3,500-7,000 |
| Surveys & searches | £800-2,000 | £1,000-2,500 |
| Removals | £1,000-2,000 | £1,200-2,500 |
| Mortgage fees | £1,000-2,000 | £1,500-2,500 |
| Overlap costs/temp housing | £2,000-5,000 | £3,000-6,000 |
| TOTAL MOVING COSTS | £37,600-46,800 | £53,950-64,250 |
Key insight: Just to move laterally (same value property), you'll spend £37k-47k minimum. This doesn't include any actual upgrade in property value.
Extension Costs vs Space Gained
| Extension Type | Space Gained | Total Cost | Value Added |
|---|---|---|---|
| Single-storey rear (20m²) | 20m² (215 sq ft) | £40,000-60,000 | £40,000-80,000 |
| Side return (12m²) | 12m² (129 sq ft) | £30,000-45,000 | £35,000-65,000 |
| Two-storey rear (40m²) | 40m² (430 sq ft) | £88,000-120,000 | £80,000-140,000 |
| Loft conversion (30m²) | 30m² (323 sq ft) | £54,000-75,000 | £40,000-70,000 |
| Basement (40m²) | 40m² (430 sq ft) | £120,000-180,000 | £120,000-200,000 |
ROI: Extensions typically return 80-150% of investment in property value increase
For the cost of moving laterally (£37k-47k), you can build a quality 20m² single-storey extension that:
- Adds equivalent bedroom/living space without moving
- Increases property value by £40k-80k
- Keeps you in same location (schools, community, commute)
- No stamp duty, estate agent fees, or moving stress
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Compare extension costs vs moving costs for your specific property. Get instant estimates for rear, side return, loft, and basement extensions.
When to Extend vs When to Move
Extend If:
- You love your location and neighborhood
- Children settled in local schools
- Need 1-2 extra rooms, not whole house upgrade
- Property has potential for value addition
- Want to avoid 2025 stamp duty increases
- Have garden space or scope for loft/side return
- Fixed mortgage rate ending soon (avoid remortgage)
Move If:
- Need to change location (work, family, schools)
- Fundamental property issues (damp, layout, structure)
- Need 3+ more bedrooms (extension too costly)
- No scope to extend (small plot, planning restrictions)
- Want fundamentally different property type
- Downsizing (release equity)
- Property already at maximum value for area
Not sure if you should extend or move?
Get a free extension estimate to compare costs →Hidden Factors: Beyond Just Money
Time & Stress
| Factor | Moving | Extending |
|---|---|---|
| Timeline | 3-6 months (search to completion) | 6-12 months (planning to finish) |
| Disruption | High - full house pack, move, unpack | Medium - live in house during build |
| Uncertainty | High - chain delays, fall-throughs | Low - controlled process |
| Emotional toll | Very high - leaving community | Moderate - construction noise |
Location Value
Your location may appreciate faster than you can upgrade via moving. If you're in a desirable London area (good schools, transport, amenities), extending lets you:
- Capture ongoing area appreciation
- Maximize property value in premium location
- Maintain access to best schools/amenities
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Frequently Asked Questions
Is it cheaper to extend or move house in London?
For most London homeowners, extending is cheaper than moving. Stamp duty alone costs £21,650 on average London property (£543k). Add £15k-25k for estate agent fees, legal costs, and removals. Total moving costs: £36k-50k minimum. A quality 20m² extension costs £40k-60k but adds similar space without relocation stress or 2025 stamp duty increases.
How much is stamp duty in London 2025?
After April 2025 changes, stamp duty increased significantly. First-time buyer threshold dropped from £425k to £300k. Home mover threshold dropped from £250k to £125k. On average London property (£543k), stamp duty is £21,650. On £750k property: £32,500. On £1m property: £57,500. Additional 5% surcharge applies to second homes.
How much value does an extension add to a London property?
Extensions typically add 15-25% to property value in London. Single-storey rear extension (20m²): adds £40k-80k. Two-storey extension (40m²): adds £80k-140k. Side return: adds £35k-65k. Loft conversion: adds £40k-70k. ROI typically 80-150% depending on area and quality. Best ROI in high-value areas like Zones 1-3.
What are the hidden costs of moving house?
Moving costs beyond stamp duty: Estate agent fees (1-3% of value = £5k-16k on £543k), solicitor fees (£1,500-3,000), surveys (£400-1,500), removals (£800-2,000), EPC (£80-120), mortgage arrangement (£1,000-2,000), overlap rent/mortgage (£2k-5k), utility connections, redecoration. Total hidden costs: £15k-30k.
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Or email hello@mayfairstudio.co.uk · 07405 920944