The best replacement for cost of debt is cost of equity.

The best alternatives to cost of debt are rated as following:
★★★★★  cost of equity
★★★★  cost of capital
★★★  equity
★★  cost of preferred stock
★  wacc
★  effective annual rate
★  coupon rate
  return on debt

Your alternative for cost of debt is not listed? Suggest!
Speaking about cost of debt, one probably shouldn't forget about debt beta.

Other search terms related to cost of debt and their ratings are:
★★★★★ debt beta
You have in mind a companion for cost of debt and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of cost of debt in all years. Click on graph for more.
cost of debt
cost of equity
cost of capital