Most first-time flippers lose money because they skip the math. Here are the 5 numbers I check before I even drive to a property:

1. ARV (After Repair Value) — What's the house worth fully renovated? Pull 3-5 comps within 0.5 miles that sold in the last 90 days. If you can't find comps, walk away.

2. The 70% Rule — Never pay more than 70% of ARV minus repair costs. Example: ARV is $200K, repairs are $40K → max offer is $100K. This is your margin of safety.

3. Holding costs — Every month you own the property, you're bleeding money. Insurance, taxes, utilities, loan interest. Budget $2-3K/month minimum.

4. Rehab budget (with 20% buffer) — Contractors will go over budget. Materials will cost more than quoted. Always pad your rehab estimate by 20%. If the deal doesn't work with the buffer, it doesn't work.

5. Days on market for comps — If similar renovated homes are sitting for 60+ days, your market is slow. That means higher holding costs and more risk.

Run these 5 numbers before you get emotionally attached to any deal. The spreadsheet doesn't lie.

If you want to go deeper — deal sourcing, financing strategies, live deal breakdowns — that's what we do inside Flip Mastery every week.