70 Percent Rule Explained: When It Works, When It Fails, and Smarter Alternatives

Overview

If you analyze flip deals long enough, you will hear some version of this formula:

Maximum Allowable Offer (MAO) = After Repair Value (ARV) x 70% - Repair Costs

That is the classic 70 percent rule. In plain language, it says a flipper should aim to buy a property for no more than 70 percent of its finished value, after subtracting the rehab budget. The remaining 30 percent is meant to cover selling costs, financing, holding costs, surprises, and profit.

As a quick screen, that can be useful. It forces discipline. It reminds investors that the purchase price is only one part of the deal. And it reflects a basic truth from the broader fix-and-flip process: profitable house flipping depends on buying right, budgeting accurately, managing the renovation well, and selling into real buyer demand.

But the 70 percent rule is a shortcut, not a universal truth. It was popular because it gave flippers a simple house flipping formula for rough deal triage. The problem is that markets are not uniform. A light cosmetic project in a fast-moving neighborhood does not carry the same risk as a heavy structural rehab in a slow market. A cash buyer has different costs than someone using short-term debt. A six-week flip has different holding costs than a six-month one.

So the real question is not whether the rule is “right.” The better question is: what assumptions are hiding inside it?

Once you unpack those assumptions, the rule becomes more useful. You can decide when 70 percent is conservative enough, when it is too aggressive, and when you should use a different spread entirely.

For a broader walkthrough of deal math, profit, and carrying costs, see House Flipping Calculator Guide: How to Estimate Profit, Holding Costs, and ROI.

How to estimate

The goal is not to memorize one ratio. The goal is to arrive at a purchase price that leaves enough room for the full project to work. A better process starts with the same foundation as the 70 percent rule, then replaces the hidden assumptions with visible inputs.

Step 1: Estimate ARV carefully

ARV is the resale value after renovation. This is the most sensitive input in almost any fix and flip analysis. If your ARV is inflated, the entire deal can look better than it is.

Use comparable sales that match the finished product you realistically plan to deliver, not the nicest home in the zip code. Stay close on location, style, size, bed and bath count, lot characteristics, and condition. If your renovation plan is a solid mid-market update, your comps should reflect that level of finish rather than luxury retail comps.

Be especially cautious when the market is changing quickly. In a softer market, older sold comps may overstate current retail value. In a rising market, active listings may create optimism that never closes. When in doubt, use the more conservative interpretation.

Step 2: Build a rehab budget from a scope, not a guess

The second input is repairs, but this is where many new investors are too casual. “Needs about 40 grand” is not a budget. It is an opinion.

Create a line-by-line scope of work: demolition, framing, electrical, plumbing, HVAC, roofing, windows, kitchen, baths, flooring, paint, landscaping, permits, dumpsters, cleaning, and punch work. Cosmetic projects and heavy rehabs should not be blended together. Labor availability, material choices, and code issues can change the cost profile fast.

A deal is only as accurate as the renovation budget behind it. If you need a framework, review How to Build a Rehab Budget That Protects Your Profit and Room-by-Room Renovation Guide: Cost Ranges, Design Choices and Value Drivers.

Step 3: Replace the fixed 30 percent spread with actual costs

This is the smarter alternative.

Instead of assuming the remaining 30 percent covers everything, estimate:

• Purchase closing costs
• Financing costs, including points, interest, lender fees, and draw costs if applicable
• Holding costs, such as taxes, insurance, utilities, lawn care, HOA dues, and maintenance
• Selling costs, including agent commissions where relevant, seller concessions, transfer fees, staging, and closing costs
• Contingency for unknowns in the rehab
• Target profit for the risk you are taking

That produces a more durable MAO formula:

MAO = ARV - Rehab - Purchase Costs - Financing - Holding Costs - Selling Costs - Contingency - Target Profit

This does not fit on a bumper sticker, but it is far better for real decisions.

Step 4: Pressure-test the deal with scenarios

Before making an offer, run at least three versions:

• Base case: your best realistic estimate
• Conservative case: slightly lower ARV, slightly higher rehab, slightly longer timeline
• Optimistic case: only for context, not for underwriting

If the deal only works in the optimistic case, it probably does not work.

Timeline matters here. A flip that sits longer than expected can lose profit through interest, utilities, taxes, and market drift. For planning around schedule risk, see A Realistic Step-by-Step Timeline for Completing a House Flip and Turnover Speed: Practical Strategies to Shorten Your Flip Timeline Without Sacrificing Quality.

Inputs and assumptions

Here is where the 70 percent rule works, where it fails, and how to decide whether to use it at all.

When the 70 percent rule works reasonably well

The rule is most useful as a first-pass filter in markets and projects where the built-in 30 percent spread roughly matches reality. That often means:

• Standard entry-level or mid-market homes with clear comparable sales
• Moderate cosmetic or light-to-medium rehab rather than major structural work
• Predictable retail demand
• Manageable project timelines
• Typical financing and selling costs

In those cases, the rule can help you sort through leads quickly. It is especially helpful if you are screening many potential properties and only want to spend deeper analysis time on deals that pass a rough test.

When the 70 percent rule tends to fail

The rule becomes less reliable when any major assumption changes.

1. Expensive financing.
If your deal relies on costly short-term debt, the generic 30 percent spread can disappear faster than expected. This is one reason many flippers refine their numbers instead of relying on a fixed percentage.

2. Longer timelines.
Delays from permits, contractor scheduling, inspections, weather, change orders, or slower resale can increase holding costs materially. The source material emphasizes that successful flipping is not just about buying but also about reliable contractors, planning, and getting to a willing buyer. Those operational realities affect MAO.

3. Heavy rehab risk.
Foundation problems, layout changes, old electrical systems, plumbing replacements, environmental issues, and extensive code upgrades create uncertainty. A simple house flipping formula is weakest when unknowns are largest.

4. Thin or unstable comps.
If ARV depends on a small number of sales, aspirational finishes, or a fast-changing market, your margin for error should be wider than a fixed rule implies.

5. Highly competitive neighborhoods.
In some markets, experienced operators knowingly buy above a textbook 70 percent threshold because they have lower costs, better crews, stronger local knowledge, or alternate exits such as renting or refinancing. That does not make the deal safe for every buyer.

6. Lower-priced homes with strong demand.
Some lower-priced, high-turnover houses can still work above 70 percent if selling costs and time to resale are relatively favorable. Again, the right answer comes from the numbers, not the slogan.

A safer evergreen interpretation

The safest long-term way to think about the 70 percent rule is this: it is a screening benchmark, not a valuation method. Use it to sort leads. Do not use it as the final word on what to offer.

If you want one practical takeaway, make it this: the right MAO is the price that leaves room for your actual costs and target profit, not the price that happens to fit a popular percentage.

Smarter alternatives to a fixed percentage

There are three strong alternatives.

1. Margin-based MAO.
Start with ARV, then back out each cost category and your required profit. This is the most flexible and the best default.

2. Risk-adjusted spread.
If you like the speed of the 70 percent rule, customize the percentage. For cleaner cosmetic projects in highly liquid areas, your spread may differ from heavier projects in slower areas. The point is not to chase a higher offer. The point is to align the spread with real risk.

3. Dual-exit analysis.
Analyze the same property as a flip and as a rental. The source material notes that buy-and-hold can become more appealing in some market conditions. If a property misses your flip threshold but works as a rental after renovation, that can change your decision or negotiation strategy.

For thinking through value-add upgrades that support ARV rather than vanity spending, see Prioritize Renovations: Which Upgrades Give the Biggest ARV Boost.

Worked examples

These examples show how the same property can look different under the 70 percent rule and a more detailed MAO formula.

Example 1: The rule works as a quick filter

You estimate a realistic ARV of $300,000. Your detailed contractor walkthrough suggests $50,000 in repairs.

70 percent rule:
MAO = $300,000 x 70% - $50,000 = $160,000

If the seller wants $210,000, the deal likely fails your initial screen. You can move on quickly unless there is a compelling reason to believe the rehab is overstated, the ARV is understated, or you have a stronger exit strategy.

Now imagine your detailed cost review shows:

• Purchase and closing costs: modest but real
• Financing: meaningful but manageable
• Holding costs for a normal timeline: manageable
• Selling costs: standard retail sale expenses
• Contingency: necessary but not excessive
• Target profit: adequate for the project risk

That detailed analysis may land near the same conclusion as the 70 percent rule. In that case, the shortcut did its job.

Example 2: The rule is too aggressive

ARV looks like $350,000 and repairs seem to be $60,000. The 70 percent rule gives:

MAO = $350,000 x 70% - $60,000 = $185,000

But this property needs permits, has a slower contractor schedule, and requires costly short-term financing. You also expect a longer selling season because comparable homes take time to move.

In a detailed model, financing and holding costs rise, contingency should be larger, and profit requirements should reflect the added uncertainty. Your real MAO may end up well below $185,000. If you rely only on the rule, you could buy a project with little room for error.

Example 3: The rule is too conservative

Suppose a house sits in a highly liquid neighborhood with strong buyer demand, clean cosmetic rehab, quick contractor access, and a realistic fast resale. Your ARV and repair numbers are solid. The 70 percent rule says the deal does not work, but only by a narrow margin.

A detailed model may show lower-than-average timeline risk and lower carrying costs than the generic 30 percent spread assumes. The deal might still meet your target profit at a slightly higher offer price.

This is where experienced local operators sometimes outperform broad formulas. They are not ignoring risk. They just know the assumptions better.

Example 4: The deal should be analyzed as a rental too

A seller will not accept your flip MAO, but the location has durable rental demand. If the renovation creates a stable rent-ready property, your best move may be to compare the flip outcome with a hold strategy rather than force the numbers into a fix-and-flip box.

The source material makes this point indirectly: market conditions can make buy-and-hold more attractive at certain times. That is a reminder that deal analysis is not just about one formula. It is about matching the property to the best exit.

If you want real-world pattern recognition, review Real Flip Case Studies with Templates: Breakdowns of Costs, Timelines, and Key Decisions.

When to recalculate

The best deal formula is only as good as its latest inputs. This is a topic you should revisit whenever pricing inputs change or rates move.

Recalculate your MAO when:

• Comparable sales shift. A new sale can support or weaken your ARV.
• Contractor pricing changes. Labor and materials rarely stay fixed for long.
• Financing terms change. Rate movements, points, or lender fees can alter the spread quickly.
• The scope of work changes. Once walls open up, unknowns can become real line items.
• The timeline slips. Every added month affects holding costs and may affect sale timing.
• Buyer demand softens or strengthens. Faster or slower resale changes your expected carry and pricing confidence.
• Your exit strategy changes. If a flip turns into a rental or refinance candidate, the whole analysis should be updated.

Here is a practical routine you can use on every deal:

1. Run the 70 percent rule as a quick lead filter.
2. If it passes or is close, build a full MAO from line-item costs.
3. Use a written scope of work and confirm pricing with contractors.
4. Review permits, insurance, and legal requirements early so timeline risk is visible. See Protecting Your Flip: Insurance, Permits, and Legal Must-Haves.
5. Stress-test ARV, rehab, and timeline with conservative assumptions.
6. Revisit the model before contracting, before starting rehab, and before listing for sale.
7. If the margin is thin, compare sell, rent, or refinance outcomes instead of forcing a flip. After the renovation phase, a smoother resale process also matters; see The Flipper’s Post-Sale Playbook: Smooth Closings, Buyer Repairs, and Preparing Your Next Project.

One final note: formulas do not replace execution. The source material makes clear that profitable flipping depends on more than buying low. You need reliable contractors, affordable financing, planning discipline, and an actual buyer at the end. If you want a stronger renovation team, use a structured vetting process such as Interviewing and Hiring Contractors: A Practical Checklist and Red Flags.

Bottom line: The 70 percent rule is a useful starting point for how to analyze flip deals, but it is not a complete decision tool. Use it to screen. Use a detailed MAO formula to buy. And recalculate whenever ARV, rehab costs, financing, or market speed changes. That is how you turn a popular rule of thumb into a repeatable system.