Operating Cash Burn Calculator

Assets burn cash before stabilization. This calculator sizes monthly burn and months until turn-positive.

Monthly revenue

Monthly opex

Monthly debt service

Cash reserves

Monthly burn

$18,000

Months of runway

26.7

Annual burn

$216,000

How the math works

Burn = opex + debt service − revenue. Runway = reserves ÷ burn.

Under 6 months runway = trigger for capital plan. Negotiate bridge extension, cut controllable opex, or raise capital before month 4. Waiting until month 2 leaves no options.

How to Use

Enter monthly revenue.
Enter monthly operating expenses.
Enter monthly debt service.
Enter cash reserves.
Read burn and runway.

Frequently Asked Questions

Typical stabilization burn?

Lease-up multifamily 6-12 months of $20-50k/month burn. Value-add rehab often 9-18 months. Office lease-up varies widely — anchor tenant can flip burn overnight.

Reserve sizing?

Minimum 12-18 months of peak projected burn plus 3-month operating buffer. Lenders require reserve accounts for first-year burn on bridge and construction takeouts.

Extending runway?

Reduce OpEx during lease-up (skeleton crew until occupancy supports full staff). Negotiate IO period with lender. Secondary capital commitment at origination avoids mid-lease-up crisis capital raise.

How often should I rerun this?

Rerun this calculator whenever inputs change materially — new rent roll data, rate moves, loan balance updates, or quarterly operating data. For active deals, monthly refresh is typical. For stabilized assets under monitoring, quarterly is fine. Treat the output as a decision tool, not a one-time answer — market conditions evolve and so should your analysis.