Definition
Interest rate sensitivity shows how changes in rates affect interest expense and cash flow, especially for floating-rate debt.
Formula
Interest change = floating debt balance * rate change
Example
If floating debt is $5M, a 1% rate increase adds $50k annual interest.
How to use it
- Model multiple rate scenarios to stress-test coverage.
- Consider hedges if rate exposure is large.
Common mistakes
- Ignoring base rate floors or caps in the debt agreement.
- Using ending debt balance instead of average balance.
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 "Interest Rate Sensitivity" 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.
- Read the related guide (e.g., Loan amortization: how monthly payments and total interest work) for context and common pitfalls.
Where to use this on MetricKit
Calculators
- 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.
- Discounted Payback Period Calculator: Estimate discounted payback period using a discount rate (and compare to simple payback).
Guides
- 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.
- Runway and burn: gross vs net burn, working capital, and cash levers: A practical guide to runway: compute net burn, understand why cash differs from profit, and how working capital and collections change runway.