Idaho real estate glossary

How the 70% Rule Factors Holding Costs into Initial Offer Prices

The 70% rule is a foundational real estate investment formula used to calculate a Maximum Allowable Offer (MAO) for fix-and-flip properties. While holding costs are not a separate deduction within the primary formula, they are implicitly accounted for within the 30% margin reserved after purchase and renovation expenses are subtracted from the After-Repair Value (ARV).

Updated with grounded research as of 2026-10-06.

The short answer

In real estate investing, the 70% rule does not treat holding costs as a distinct, line-item subtraction from the After-Repair Value (ARV). Instead, holding costs are effectively bundled into the 30% buffer remaining after the purchase price and renovation costs are accounted for. This remaining percentage must cover all carry expenses—such as Idaho property taxes, insurance, utilities, HOA fees, and financing interest—as well as selling commissions, closing costs, and the investor’s desired profit margin.

Key facts

The 70% Rule Formula
Maximum Allowable Offer (MAO) = (After-Repair Value [ARV] × 0.70) - Estimated Repair Costs
The Function of the 30% Buffer
The 30% portion not allocated to the purchase or repairs serves as a financial reservoir to absorb holding costs, transaction fees, and expected profit.

Understanding the 30% Margin

For Idaho investors, the 30% 'buffer' is a critical component of the initial offer strategy. Because the 70% rule is a high-level screening tool, it relies on this margin to mitigate the uncertainty of project timelines. If a renovation takes longer than anticipated, holding costs—such as continued loan interest or property taxes—will erode this 30% buffer before they eat into the project's profit.

  • Property taxes and insurance premiums
  • Utilities (electric, water, gas, sewer)
  • Homeowners association (HOA) fees
  • Financing interest and loan points

Limitations of the Rule of Thumb

The 70% rule is designed to be a quick filter, not a substitute for a detailed project pro forma. It makes broad assumptions about standard holding periods and transaction fees that may not align with current market conditions in specific Idaho regions. Investors must recognize that in competitive markets, fixed costs can disproportionately consume the 30% buffer.

Adapting the Multiplier for Market Conditions

Successful investors often adjust the 70% multiplier based on local market factors. In highly competitive environments, some investors may use a 75% or 80% multiplier to remain competitive in their offers, accepting lower margins as a trade-off for higher volume or speed. Conversely, in lower-priced markets, investors may tighten the multiplier to 60-65% because fixed holding costs often represent a larger percentage of the total budget.

Common questions

Does the 70% rule guarantee a profit?

No. The 70% rule is a rough screening tool. It does not account for specific site conditions, unexpected construction delays, or localized market fluctuations in Idaho that can significantly increase holding costs beyond the standard 30% estimate.

When should I perform a detailed pro forma instead of using the 70% rule?

You should always move from a rule-of-thumb calculation to a detailed, line-item pro forma analysis before submitting an offer. The pro forma should specifically calculate projected monthly holding costs based on the estimated project timeline for your specific property.

Related Idaho questions

  • What are common holding costs for a fix-and-flip project?
  • When should an investor adjust the 70% rule to 65% or 75%?
  • How does the 70% rule differ from BRRRR investment calculations?

Sources and verification