The short version
Residential investor DSCR (the dscr.broker worksheet) is Gross Monthly Rent ÷ Monthly PITIA. Commercial DSCR on this desk is NOI ÷ Annual Debt Service.
Do not run a mixed-use or small CRE file through rent ÷ PITIA and call it commercial. Taxes, insurance, and HOA are already inside NOI’s expense stack on a CRE file — they are not added again as PITIA on top of NOI.
What changes on a CRE file
- Income: NOI (or T-12 / rent roll minus OpEx), not a single-unit market rent.
- Debt service: Annual P&I or IO on the commercial loan — not monthly PITIA.
- Companion metrics: Debt yield, cap rate, BTCF, cash-on-cash. Residential DSCR desks rarely lead with those.
- Leverage: Educational CRE LTV bands are often lower than 1–4 unit investor LTV chatter. Chips on the calculator are assumptions, not policy.
When to use which desk
1–4 unit rentals held as investments: dscr.broker. Mixed-use, small CRE, investor-held commercial: this site. Short purchase-rehab-exit: fixandflip.broker or hardmoney.broker.
The CRE calculator is Engine C. It will not pretend to be the residential DSCR tool.
Do not mix
CRE: NOI ÷ Annual Debt Service
Residential: Gross Monthly Rent ÷ Monthly PITIA