Definition
OpEx are ongoing operating costs (salaries, rent, marketing). OpEx drives operating margin and burn.
Why this matters
This term matters because cash timing and risk are usually the difference between a plan that works on paper and a plan that survives. Use consistent definitions so decisions are comparable over time.
Practical checklist
- Write a 1-line definition for "OpEx (Operating Expenses)" that your team will use consistently.
- Keep the time window consistent (weekly/monthly/quarterly) when comparing trends.
- Segment results (channel/plan/cohort) before drawing big conclusions from blended averages.
- Sanity-check with a related calculator from the same category on MetricKit.
- Document common pitfalls so the metric doesn't get gamed.
Where to use this on MetricKit
Calculators
- Real Return (Inflation-adjusted) Calculator: Convert nominal return into real return given an inflation rate (and compare the difference).
- Deferred Revenue Rollforward Calculator: Bridge billings to recognized revenue by rolling deferred revenue forward for a period.
- Break-even Revenue Calculator: Estimate the revenue needed to break even given fixed costs and gross margin.
- NPV Calculator: Calculate net present value (NPV) from initial investment, annual cash flow, years, and discount rate.
- IRR Calculator: Estimate internal rate of return (IRR) for an investment using yearly cash flows.
Guides
- ARR valuation sensitivity: a simple multiple grid for scenarios: Use a 3*3 grid to see how valuation changes when ARR and the market multiple move, and avoid false precision from a single multiple.
- DCF sensitivity: discount rate vs terminal growth (how to read it): A practical guide to DCF sensitivity analysis: why valuations swing, how to pick ranges, and how to avoid terminal value traps.
- Loan amortization: how monthly payments and total interest work: A practical guide to loan amortization: monthly payment formula, why interest dominates early, and how term and rate affect total interest.
- Interest expense: definition, formula, and how to calculate: Interest expense explained: what it is, the formula, how to calculate it, and how net interest expense works.
- APR vs APY: how compounding changes the effective rate: A practical guide to APR vs APY: what each means, how to convert between them, and common comparison mistakes.