COCOMO Effort Estimation Map

Project Parameters

Project size 120 KLOC

Development mode

Effort Adjustment Factor 1.00

Compare all 3 modes on curve

Drag anywhere on the heat map to set project size and EAF directly — it's a live map of the same surface the curve plots.

Estimate

Effort E

— PM

Schedule D

— mo

Average team size

— people

Semi-detached: coefficients a=3.0, b=1.12 — a mixed-experience team on a moderately novel system.

How it works

The COCOMO (Constructive Cost Model, Boehm 1981) estimates software effort from a single size measure — thousands of lines of code (KLOC) — plus a mode that captures how novel and constrained the project is:

Effort E = a x (KLOC)^b x EAF   [person-months]
Duration D = c x E^d           [months]
Team size  = E / D             [average people]

Organic:        a=2.4  b=1.05  c=2.5  d=0.38
Semi-detached:  a=3.0  b=1.12  c=2.5  d=0.35
Embedded:       a=3.6  b=1.20  c=2.5  d=0.32

The exponent b > 1 is the key insight: effort grows faster than code size, because a bigger system needs proportionally more integration, coordination and communication overhead — doubling KLOC more than doubles the effort. The Effort Adjustment Factor (EAF) is the Intermediate-COCOMO multiplier applied on top, aggregating cost drivers like required reliability, team capability and tooling (typically 0.7 for a very favorable project down to 1.4 for a difficult one).

Heat map (top) — every pixel is E = a·KLOC^b·EAF for that pixel's own (KLOC, EAF), log-scaled and colour-mapped from blue (cheap) to red (expensive). The crosshair is your current choice; drag anywhere to jump there.
Curve (bottom) — a log-log slice through the surface at your current EAF: effort vs KLOC for the selected mode (solid) and, when comparison is on, the other two modes (dashed) so you can see how the exponent b changes the curve's steepness.
Development mode — swaps (a, b, c, d) and redraws both views, since the exponent itself changes.
Auto-sweep — animates the KLOC slider back and forth so you can watch the marker travel the curve continuously.

Effort surface — KLOC x EAF

Effort vs project size (log-log)

Semi-detached Organic Embedded