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COCOMO Effort Estimate Calculator

Work out cocomo effort estimate instantly with clear inputs, formula shown and shareable results.

About COCOMO Effort Estimate Calculator

COCOMO estimates effort as a x KLOC^b multiplied by an adjustment factor, with mode-specific coefficients: organic uses 2.4 and 1.05, semi-detached 3.0 and 1.12, embedded 3.6 and 1.20. Because the exponent exceeds 1, effort grows super-linearly with size — doubling the code more than doubles the work, which is the quantitative case for smaller systems.

Formula

Basic COCOMO

effort = a x KLOC^b x EAF person-months; duration = 2.5 x effort^d months; staff = effort / duration

Worked example

With the default values below, COCOMO Effort Estimate Calculator returns Effort of 499.8. Change any input above and every figure here is recalculated in your browser.

Inputs used

Thousands of source linesminimum 0.1 KLOC
85 KLOC
Project modeone of Organic - small, familiar team, Semi-detached - medium complexity, Embedded - tight constraints
Semi-detached - medium complexity
Combined effort adjustment factoraccepts 0.1–5 x
1.15 x

Results

Effort
499.8 person-months
Schedule
22.0 months
Average team size
22.7 people
Productivity
0.170 KLOC/pm

Step by step

  1. 1Values used
  2. 2Basic COCOMO
  3. 3Effort= 499.8 person-months
  4. 4Schedule= 22.0 months
  5. 5Average team size= 22.7 people
  6. 6Productivity= 0.170 KLOC/pm

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges 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

Is COCOMO still useful?

As a sanity check on order of magnitude and on the diseconomy of scale, yes. As a predictive tool for iterative delivery it has largely been replaced by empirical velocity measurement.

Why does the schedule not shrink with more people?

The duration formula grows with effort at only the 0.35 power, reflecting Brooks's observation that adding people to a late project makes it later.

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