Quick guide
How to use this calculator
- Enter only the market, accounting, cash-flow, rate, or timing assumptions named by the fields.
- Keep currencies, periods, per-share values, and percentage conventions consistent.
- Review the formula and limitations before interpreting or comparing the result.
Calculation method
Calculation method
After-tax cost of debt = pre-tax cost × (1 − entered tax rate).
Fixed decimal inputs and scalar arithmetic remain exact until display. Root and growth calculations are explicitly marked approximate.
Worked example
Worked example
A 6% pre-tax debt cost and 25% tax rate produce 4.5% after-tax cost.
After-tax cost of debt = pre-tax cost × (1 − entered tax rate).
Supported inputs
Precision and limits
Visible input limits
Fixed decimals accept up to 30 digits and 12 decimal places and are capped at an absolute value of 1e12 per input. Rates are capped at 1000%; narrower domains are validated by the formula.
International scope
No currency, exchange, live security price, accounting standard, tax jurisdiction, market convention, settlement rule, or regulatory disclosure is selected automatically.
Decision boundary
Results are calculations from visitor-entered assumptions, not market data, forecasts, financial advice, suitability assessments, fair-value opinions, or recommendations.
Calculator-specific assumptions
The calculator assumes the entered tax rate applies to deductible interest. It does not determine deductibility, limits, timing, or jurisdiction-specific treatment.