The difference between a profitable flip and a financial disaster often comes down to one thing: accurate deal analysis before buying. Successful investors have clear systems and criteria — they don't make decisions based on gut feeling.
The 70% Rule Explained
The 70% Rule states that you should not pay more than 70% of the After Repair Value (ARV) minus repair costs:
Maximum Offer = ARV × 70% − Repair Costs
Practical Example
- ARV (value after renovation): €200,000
- Estimated renovation costs: €30,000
- Maximum offer: €200,000 × 70% − €30,000 = €110,000
If the seller asks €130,000, the deal doesn't work with the 70% Rule. Either negotiate down or pass.
Why 70% and Not 80%?
The remaining 30% covers:
- Acquisition costs (IMT, IS, notary): ~3–5%
- Financing costs (interest, fees): ~3–6%
- Holding costs (IMI, insurance, utilities): ~1–2%
- Sale commission (agent + VAT): ~5–6%
- Profit margin: ~10–15%
The 5 Profit Levers in Fix & Flip
1. Purchase Price
Profit is made at purchase, not at sale. Every €10,000 saved at purchase is €10,000 of guaranteed profit.
2. Renovation Cost Control
Renovation is where most flippers lose money. Main causes of cost overruns:
| Cause | Typical Impact | Prevention |
|---|---|---|
| Structural surprises | +€5,000–€20,000 | Detailed pre-purchase inspection |
| Scope changes | +€2,000–€10,000 | Define scope before starting |
| Construction delays | +€500–€2,000/month | Contracts with penalties |
3. Execution Speed
Each additional month of holding costs:
- Financing interest: €500–€2,000/month
- IMI and insurance: €100–€300/month
- Utilities: €50–€150/month
- Total: €650–€2,450/month
4. Sale Price Maximisation
| Strategy | Price Impact | Cost |
|---|---|---|
| Professional home staging | +2–5% | €500–€2,000 |
| Professional photography + 3D tour | +1–3% | €300–€800 |
| Kerb appeal improvements | +1–3% | €500–€2,000 |
5. Tax Structure
In Portugal, capital gains from properties sold within 2 years are taxed at 50% of the gain in IRS (for residents). For non-residents, the rate is 28% on 100% of the gain.
Deal Evaluation Metrics
| Metric | Formula | Benchmark |
|---|---|---|
| Gross margin | (Sale − Purchase − Renovation) / Sale | > 20% |
| ROI | Profit / Own capital invested | > 25%/year |
| Annualised ROE | (Profit / Own capital) × (12 / months) | > 30% |
Use the Fix & Flip Calculator to automate this analysis and ensure every deal meets your minimum profitability criteria.
The 70% Rule in Practice
The 70% Rule states your maximum purchase price should be no more than 70% of the After Repair Value minus renovation costs. For a property with ARV of €300,000 and €40,000 renovation costs, your maximum offer should be €170,000.
However, adjust this rule based on local conditions. In hot markets like Lisbon or London, investors work with 75-80% because properties appreciate during renovation. In slower markets, use 65% to account for longer holding times.
Renovation Scope: Where the Money Is
Focus your budget on high-ROI improvements: kitchen modernisation (150-300% return), bathroom updates, fresh paint, new flooring, improved lighting, and kerb appeal. Medium-ROI improvements include additional bedrooms, en-suites, and open-plan conversions. Avoid over-improving beyond neighbourhood standards.
Use our Renovation Calculator to estimate costs for each improvement category.
Holding Costs: The Silent Profit Killer
Every month you hold a property costs money. On a €200,000 purchase with 80% LTV at 4% interest, monthly holding costs (mortgage, insurance, council tax, utilities, security) can reach €1,500-€2,500. A renovation taking 6 months instead of 3 costs an extra €4,500-€7,500 in pure holding costs.
Exit Strategy Planning
Before purchasing, define your exit strategy: quick cosmetic flip (3-6 months), value-add flip (6-12 months), flip-to-rent via BRRRR (use our BRRRR Calculator), or development flip (12-24 months). Each has different risk/reward profiles and capital requirements.
Building Your Flip Team
Successful flipping requires a reliable team of professionals working in coordination:
Key team members: Experienced contractor (ideally with multiple crews for parallel workstreams), architect/designer for layout optimisation, solicitor specialising in property transactions, mortgage broker for fast finance, and estate agent with strong local market knowledge.
Contractor management: Never pay more than 30% upfront. Structure payments in 3-4 milestones tied to completed work. Visit the site at least twice weekly during active renovation. Document everything with photos and written instructions.
Speed multipliers: The fastest flippers complete projects 40-50% quicker by: ordering all materials before works begin, scheduling trades in parallel where possible (electrician and plumber can work simultaneously in different rooms), and having backup suppliers for critical materials.
Deal sourcing: The best deals rarely appear on public portals. Build relationships with local agents who can alert you to motivated sellers, attend property auctions (e-leilões.pt in Portugal), network with solicitors handling probate sales, and drive target neighbourhoods looking for signs of distress (overgrown gardens, boarded windows).