Data Sources

Why should I customize assumptions?

Learn why rent, vacancy, financing, taxes, and reserves can move outputs faster than most beginners expect.

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Answer

Default assumptions help you get to an initial answer quickly, but the best analysis comes from inputs that reflect your actual plan.

If you know your lender quote, contractor estimate, or target rent, updating those values gives you a more realistic analysis.

Related guides

Open the rental property calculator guideUnderstand monthly cash flow inputs

Related questions

How does DealPrism estimate rent?Why are vacancy, management, maintenance, and CapEx included even if the property is occupied?

See how this plays out on a real deal

DealPrism helps you connect the concept to live property assumptions, scenario changes, and calculated outputs.

Analyze your own deal

DealPrism provides educational analysis based on available data and user assumptions. Results are estimates and may change if rent, taxes, insurance, financing, or other inputs are updated. This content is not financial, legal, tax, or investment advice.