The 70 Percent Rule Explained: When House Flippers Should Follow It and When to Adjust

Overview

The classic 70 percent rule is a house flipping formula used to estimate a maximum allowable offer, often shortened to MAO. In its simplest form, the rule says a flipper should pay no more than 70 percent of the property’s after repair value minus repair costs.

Basic formula:
MAO = (ARV x 70%) - Rehab Costs

Example:

• Estimated ARV: $300,000
• Rehab costs: $50,000
• MAO = ($300,000 x 0.70) - $50,000 = $160,000

That simple math is why the rule remains popular. It gives investors a fast way to screen deals before spending too much time on properties that are unlikely to work. In a busy acquisitions pipeline, speed matters. A rough formula helps you sort leads, compare opportunities, and avoid making emotional offers.

But the 70 percent rule is not a law of house flipping. It is a rough pricing guardrail built on assumptions about resale costs, holding costs on a flip, financing expense, risk, and profit margin. Those assumptions may or may not match your market, your lending terms, your renovation style, or your timeline.

That is where many new investors run into trouble. They treat the rule as if it automatically accounts for every major cost. It does not. In some cases, it can be too aggressive and cause you to overpay. In other cases, it can be too conservative and make you miss viable deals in competitive neighborhoods.

A better way to think about the 70 percent rule is this:

• Use it as an initial filter, not a final decision tool.
• Adjust it to fit your market and business model.
• Support it with a more complete fix and flip analysis before making an offer.

If you want to pressure-test your assumptions, pair this article with the site’s 70 Percent Rule Calculator: How to Set Your Maximum Allowable Offer on a House Flip and the broader House Flipping Calculator Guide: How to Estimate Profit, Holding Costs, and ROI.

The key question is not whether the rule is right or wrong. The better question is: What costs and risks is your version of the rule trying to cover?

Maintenance cycle

The 70 percent rule should be reviewed on a regular cycle because the inputs behind it change. A formula that felt disciplined six months ago can become outdated if financing gets more expensive, days on market lengthen, contractor bids rise, or buyers stop paying a premium for light cosmetic rehabs.

A practical maintenance cycle is to revisit your MAO formula on three levels:

1. Monthly quick check

Once a month, review the assumptions that drive your buy box:

• Are your ARV estimates still matching actual resale prices?
• Are contractor quotes holding steady?
• Have closing timelines stretched?
• Have lending terms changed enough to raise your carrying costs?

This does not require a full model rebuild. It is a calibration exercise. If your last few deals came in over budget or sold slower than expected, your “70” may no longer be the right number.

2. Quarterly deal review

Every quarter, compare your projected numbers against completed or near-completed projects. Focus on:

• Original ARV vs actual list price and sale price
• Original rehab budget vs actual spend
• Expected timeline vs actual timeline
• Planned profit vs realized profit

This is where a rule-of-thumb becomes a business system. If you repeatedly miss on kitchens, permit costs renovation, or resale timing, the issue is probably not the rule itself. It is the assumptions you are feeding into it.

3. Event-driven review

Revisit the rule immediately when something material changes:

• You start using new financing, such as hard money, private money, or a HELOC
• You enter a new zip code or price tier
• You shift from cosmetic flips to heavy rehabs
• You experience repeated scope creep or contractor delays
• You notice declining buyer demand for the renovation style you usually deliver

If financing is a major variable for you, the right companion read is Fix and Flip Loan Rates Guide: Hard Money vs Private Money vs HELOC. A change in financing structure can alter your real MAO even if ARV and rehab remain the same.

The maintenance lesson is simple: the 70 percent rule works best when it is treated as a living model, not a fixed slogan.

Signals that require updates

You do not need to wait for a calendar reminder if the market is already telling you your formula is stale. Here are the most important signals that your 70 percent rule needs to be updated.

Your ARV estimates are drifting

If you are consistently overestimating ARV, your MAO is too high even if the formula looks conservative on paper. This often happens when flippers:

• Use outdated comparable sales
• Choose comps from stronger streets or school zones
• Ignore lot, layout, or garage differences
• Assume top-of-market finishes will command top-of-market pricing

The fix is not to abandon the rule. It is to tighten your comps analysis real estate process. Review whether your property value estimator method matches what buyers in that micro-market actually reward.

Rehab costs are no longer predictable

The formula becomes fragile when your rehab cost estimator is weak. A $15,000 miss on repairs can erase much of the margin the rule was supposed to protect. This is especially common when investors underestimate:

• Electrical and plumbing updates
• Permit and inspection delays
• Foundation, drainage, or roof issues
• Interior scope additions after demolition

In that environment, some flippers lower the ratio from 70 percent to 65 percent or less to create more room for error. Others keep the ratio but add separate line items for contingency and sales costs before deciding on MAO.

Holding costs are climbing

If a project takes longer to complete or longer to sell, the simple formula may not protect you. The rule often assumes average carrying costs and average resale friction. But if your real project timeline stretches, your margin shrinks through:

• Interest payments
• Utilities
• Insurance
• Taxes
• Lawn, trash, or maintenance
• Price reductions caused by missed timing

This is one reason to run every promising deal through a full How to Analyze a Fix and Flip Deal Step by Step process rather than relying on the one-line MAO formula alone.

Buyer expectations have shifted

The best renovations for resale are not static. In some submarkets, buyers still reward clean, functional updates. In others, buyers compare flipped homes against polished new listings and expect a higher finish level. If that changes, both your rehab costs and your realistic ARV can move at the same time.

This is where local demand monitoring matters. Even without hard statistics, flippers can watch inventory quality, absorption patterns, price cuts, and listing presentation standards. If needed, use neighborhood demand monitoring ideas from Apply Real-Time Market Alerts to Flips: Using Dexscreener-Style Signals for Neighborhood Demand.

Your offer acceptance rate is out of balance

If every offer you submit is accepted quickly, you may be bidding too high relative to the risk. If none are accepted, your formula may be too conservative for your market or for the type of deal you are targeting. This is not proof by itself, but it is a useful operational signal.

An MAO formula should fit your acquisition channel. Direct-to-seller leads, listed distressed properties, and estate or inherited homes all behave differently. A working rule in one lane may fail in another.

Common issues

The biggest mistakes with the 70 percent rule are not mathematical. They come from using a simplified rule in situations that require more context. These are the issues that most often distort a house flipping decision.

Issue 1: Treating 70 percent as universal

There is no universal percentage that fits every deal. Higher-priced markets, lower-risk cosmetic flips, and highly competitive neighborhoods may not pencil at the same ratio as older housing stock with hidden systems issues. Some investors operate comfortably above 70 percent when they have exceptional contractor control, low-cost capital, and strong local knowledge. Others need more margin and aim lower.

The ratio should reflect risk, not habit.

Issue 2: Confusing ARV with optimistic list price

ARV should be based on realistic sold comparables, not the most flattering listing in the neighborhood. The more uncertain the ARV, the less useful the 70 percent rule becomes. If you are guessing high on resale value, the formula can give false confidence.

Before relying on MAO, confirm that your ARV reflects the actual finish level, floor plan, and buyer pool you are likely to reach.

Issue 3: Ignoring transaction and selling costs

The classic mao formula real estate shortcut often implies that the 30 percent discount covers overhead, profit, financing, and resale expenses. Sometimes it does. Sometimes it does not. If you are in a market with slower absorption, larger concessions, or higher borrowing costs, you should break out those costs separately.

That usually includes:

• Purchase closing costs
• Loan points and interest
• Insurance and taxes
• Utilities and maintenance
• Selling commissions or listing expenses
• Seller concessions
• Staging or light pre-list repairs

If you need a reminder of the full picture, the article Is House Flipping Worth It in 2026? Profit Margins, Risks, and Market Realities is a useful complement.

Issue 4: Underestimating rehab complexity

A cosmetic flip and a heavy value-add project should not be analyzed with the same casual shortcut. The more a project depends on permits, layout changes, structural work, or multiple trade sequences, the less confidence you should place in a broad rule alone.

Detailed scopes matter. If your renovation budget is weak, your MAO is weak.

For planning support, related resources include How to Find Contractors for House Flips: Vetting, Pricing, and Red Flags and House Flip Checklist: From Offer to Closing Day.

Issue 5: Using the rule after deciding you want the deal

This is a quiet but common problem. Investors often fall in love with a property, then use the 70 percent rule to justify a number they already want to pay. That reverses the process. The rule should screen emotion out, not dress it up with arithmetic.

If a deal only works when every assumption breaks your way, it probably does not work.

Issue 6: Forgetting that your own operation matters

The best house flipping formula for you depends on your real execution. Fast, disciplined operators with repeat crews and tight scopes can survive on thinner margins than investors who are still learning how to flip a house. New flippers should usually be more conservative because they are more exposed to errors in contractor management, schedule planning, and resale prep.

If that describes you, read Flipping a House for the First Time: Beginner Mistakes That Kill Profit and What Makes a Good House to Flip? A Screening Checklist for Buyers.

When to revisit

Here is the practical takeaway: revisit the 70 percent rule any time your assumptions become less reliable than the shortcut itself. In real-world fix and flip analysis, that happens more often than many investors expect.

Use this action list before you rely on your current MAO formula again:

1. Re-check your ARV method. Pull fresh comps and ask whether they truly match the finished product you plan to deliver.
2. Update your rehab cost ranges. Refresh bids, labor assumptions, and contingency percentages for your current scope level.
3. Run actual holding costs. Do not assume the rule covers them. Model financing, taxes, insurance, and timeline drag separately.
4. Adjust the percentage to risk. A lighter rehab in a proven resale pocket may justify one ratio; an older property with permit exposure may require a lower one.
5. Compare projected vs completed deals. Your own results are more useful than any popular rule.
6. Use the rule for screening, then graduate to a full model. The best habit is two-stage analysis: quick filter first, detailed underwriting second.

A practical version of that workflow looks like this:

• Step 1: Use the 70 percent rule to eliminate obviously weak deals.
• Step 2: For survivors, run a complete profit model with purchase costs, financing, rehab, contingency, holding costs, and selling costs.
• Step 3: Stress-test the deal with slower timelines and lower resale outcomes.
• Step 4: Set your final offer based on the risk-adjusted result, not the shortcut alone.

If you want one place to continue from here, start with the calculator resource at 70 Percent Rule Calculator: How to Set Your Maximum Allowable Offer on a House Flip, then move to the fuller House Flipping Calculator Guide.

The 70 percent rule remains useful because it creates discipline. It becomes dangerous only when it is used as a substitute for thinking. Keep it as a fast filter, update it on a regular cycle, and let your own completed projects teach you whether “70 percent” is still the right rule for the kind of flips you actually do.