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Technical Debt Calculator

Calculate the technical debt ratio and remediation effort for a codebase.

About Technical Debt Calculator

Expressing debt as a ratio rather than an absolute makes it comparable across codebases of different sizes. Above about 50 per cent, remediation approaches the cost of rebuilding. The ratio is most useful as a trend: a stable ratio during active development means debt is being paid down as fast as it accrues, which is the realistic goal.

Formula

Technical Debt

Debt ratio = remediation effort ÷ estimated development cost

debt ratio
Remediation cost as a share of the cost to build the code
SQALE
The model behind this ratio, where 5 per cent or less rates as A

Worked example

With the default values below, Technical Debt Calculator returns Technical Debt Ratio of 54.000%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Lines of codeminimum 1
120,000
Code smellsminimum 0
1,800
Average remediation time per issueminimum 0 min
18 min
Development cost per lineminimum 0.001 min
0.5 min
Developer hourly rateminimum 0
75

Results

Technical Debt Ratio
54.000%
Remediation Effort
540.00 h
Estimated Development Cost
1,000.00 h
Remediation Cost
$40,500.00
Maintainability Rating
E — very high debt, rewrite may be cheaper than remediation

Step by step

  1. 1Values used
  2. 2Technical Debt
  3. 3Technical Debt Ratio= 54.000
  4. 4Remediation Effort= 540.00 h
  5. 5Estimated Development Cost= 1,000.00 h
  6. 6Remediation Cost= 40,500.00
  7. 7Maintainability Rating= E — very high debt, rewrite may be cheaper than remediation

Assumptions and limits

  • The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Technical Debt calculated?

Debt ratio = remediation effort ÷ estimated development cost Expressing debt as a ratio rather than an absolute makes it comparable across codebases of different sizes. Above about 50 per cent, remediation approaches the cost of rebuilding.

Why does Technical Debt matter?

The ratio is most useful as a trend: a stable ratio during active development means debt is being paid down as fast as it accrues, which is the realistic goal.

What values do I need to enter?

This calculator takes 5 inputs: Lines of code, Code smells, Average remediation time per issue, Development cost per line, Developer hourly rate. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

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