Definition
A tax shield is the tax savings from deductible expenses such as interest or depreciation.
Formula
Tax shield = deductible expense * tax rate
Example
Interest $100k and tax rate 25% produces a $25k shield.
How to use it
- Interest tax shields raise the value of debt in many valuation models.
- The shield only matters if the company has taxable income.
Common mistakes
- Counting tax shields in periods with losses and no taxable income.
- Using statutory rates when the effective rate is materially different.
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 "Tax Shield" 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., WACC explained: how to estimate a discount rate for DCF) for context and common pitfalls.
Where to use this on MetricKit
Calculators
- DCF Sensitivity Calculator: Estimate how enterprise value changes with discount rate and terminal growth assumptions (simple 3x3 sensitivity).
- Loan Payment Calculator: Compute monthly payment, total interest, and total paid for a loan using amortization.
- APR to APY Calculator: Convert APR to APY (and APY to APR) given compounding frequency.
- 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.
Guides
- WACC explained: how to estimate a discount rate for DCF: A practical guide to WACC: what it is, how to compute it, and how to use it (carefully) as a DCF discount rate.
- DCF valuation: forecast cash flows, discount rate, and terminal value: A practical guide to DCF valuation and WACC discount rate choices: how to forecast FCF, choose a discount rate, and avoid terminal value traps.