Cost Basis (All-In Cost)
Total money invested in a property: purchase + rehab + carry + closing.
Your cost basis is every dollar you've put into a deal. It includes the purchase price, all rehab costs, closing costs on both the buy and refinance (or sale), and every month of carrying costs (loan interest, insurance, taxes, utilities) while you held the property during renovation. This is the number that determines whether you have equity or you're underwater.
Cost Basis = Purchase Price + Rehab + Closing Costs (buy) + Carry Costs + Closing Costs (refi/sell)
Kaison calculates cost basis in pipeline step 4 (calc_cost_basis). It produces both a target and P90 variant. The cost basis waterfall chart in full analysis shows exactly where every dollar goes.
Purchase: $150K. Rehab: $35K. Buy closing: $4K. 5 months carry at $1,800/mo: $9K. Refi closing: $3K. Total cost basis: $201K. If ARV is $220K, you have $19K equity (8.6% of ARV).
Beginners always forget carry costs. A 5-month rehab at 9% interest on $150K costs you $5,625 in interest alone. Kaison's carry calculator handles this automatically — but you need accurate hold time estimates.
Educational content only. Consult a CPA or attorney for advice specific to your situation.