COCOMO II Schedule Calculator
Estimate calendar time with the published COCOMO II schedule equation.
In short
Estimate calendar time with the published COCOMO II schedule equation.
Formula: TDEV = 3.67 × PM^(0.28 + 0.2 × (E − 0.91)) × SCED% ÷ 100, where PM is the nominal-schedule effort and E = 0.91 + 0.01 × ΣSF
What this calculator does
Published constants C = 3.67 and D = 0.28 with the scale exponent derived from the user's scale factors. Compression is applied exactly as published.
Use it to turn Size, Sum of the five scale factors, Product of the effort multipliers, Required schedule compression into a checked result you can compare, copy, or rerun with different assumptions.
The page shows the formula, a numeric worked example, and the assumptions that affect this professional & industry calculation.
Inputs and what they mean
- Size
- — Thousands of source lines of code..
- Sum of the five scale factors
- — Your own ratings for precedentedness, flexibility, risk resolution, team cohesion and process maturity. 18.97 is the published nominal sum..
- Product of the effort multipliers
- — Multiply your rated effort multipliers together; 1 means nominal..
- Required schedule compression
- — 100% is the nominal schedule. The published model accepts 75% to 160%..
How to use it
- Enter your own figures — the calculator never fills in a rate, price or benchmark for you.
- Press Calculate to see the result.
- Read the formula, variables, assumptions and source below the result before you rely on it.
Formula
TDEV = 3.67 × PM^(0.28 + 0.2 × (E − 0.91)) × SCED% ÷ 100, where PM is the nominal-schedule effort and E = 0.91 + 0.01 × ΣSF.
Inputs used: Size, Sum of the five scale factors, Product of the effort multipliers, Required schedule compression.
Edge handling: Size is required.; Size must be greater than zero.; Size must be no more than 100000.; Sum of the five scale factors is required.; Sum of the five scale factors cannot be negative..
Worked example
100 KSLOC on the nominal schedule
- Start with Size: 100, Sum of the five scale factors: 18.97, Product of the effort multipliers: 1, Required schedule compression: 100.
- Apply the method: TDEV = 3.67 × PM^(0.28 + 0.2 × (E − 0.91)) × SCED% ÷ 100, where PM is the nominal-schedule effort and E = 0.91 + 0.01 × ΣSF.
- The published schedule equation, with compression left at 100%.
Reading the result
The headline figure is the main answer. Any breakdown underneath shows the parts that make it up, so you can check the working and see what changes when you adjust an input.
Limitations and assumptions
- Inputs outside the supported range are rejected rather than forced into a result.
- The result depends on the values you enter for this cocomo ii schedule calculator; it does not supply missing rates, rules, prices, dates, or assumptions for you.
Reference: University of Southern California, Center for Systems and Software Engineering — COCOMO II model definition manual
Last reviewed:
Common questions
Where does this formula come from?
COCOMO II Model Definition Manual — post-architecture effort PM = A × Size^E × ΠEM with A = 2.94 and E = B + 0.01 × ΣSF (B = 0.91), and schedule TDEV = C × PM^(D + 0.2 × (E − B)) × SCED%/100 with C = 3.67 and D = 0.28. See the source link on this page.
What kind of calculation is this?
The published schedule equation applied to the post-architecture effort estimate. Check the formula, example, and limitations on this page before using the result for a real professional & industry decision.
What are its limits?
COCOMO II is a calibrated estimation model, not an exact prediction; its published accuracy is a range, not a point. Estimates are only as good as the size, scale factors and effort multipliers entered. Compression outside the published 75%–160% range is refused rather than extrapolated.
How do I use the COCOMO II Schedule Calculator?
Enter the required values for Size, Sum of the five scale factors, Product of the effort multipliers, Required schedule compression. The calculator applies the formula on this page and shows the main result with any supporting breakdown so you can check the arithmetic.
What formula does the COCOMO II Schedule Calculator use?
TDEV = 3.67 × PM^(0.28 + 0.2 × (E − 0.91)) × SCED% ÷ 100, where PM is the nominal-schedule effort and E = 0.91 + 0.01 × ΣSF The visible formula section above lists the calculation path and the edge cases the page handles, so the result can be checked without relying on the form alone. Check the formula, example, and limitations on this page before using the result for a real professional & industry decision.
Can the COCOMO II Schedule Calculator be used for exact decisions?
Use it as a calculation aid, not as a substitute for checking the underlying rule, contract, policy, or professional advice that applies to your situation. When a result depends on local rules, personal details, prices, or dates, enter those values yourself and confirm them before acting.
Formula, source and verification
The published schedule equation applied to the post-architecture effort estimate.
The question it answers: How many calendar months does this development actually need?
The formula
TDEV = 3.67 × PM^(0.28 + 0.2 × (E − 0.91)) × SCED% ÷ 100, where PM is the nominal-schedule effort and E = 0.91 + 0.01 × ΣSF
- Size — Size
- (KSLOC). Thousands of source lines of code.
- ΣSF — Sum of the five scale factors
- (points). The organisation's own ratings.
- ΠEM — Product of the effort multipliers
- (factor). The organisation's own rated multipliers.
- SCED — Required schedule compression
- (%). 100% is the nominal schedule; the published model accepts 75% to 160%.
Units: KSLOC; person-months; calendar months.
What kind of calculation this is
Estimation model. This is a published estimation model. It produces an estimate, not a measured fact, and its accuracy depends on how well your situation matches the model.
Method
Published constants C = 3.67 and D = 0.28 with the scale exponent derived from the user's scale factors. Compression is applied exactly as published.
Assumptions built into the result
- Industry: The effort estimate is the nominal-schedule effort, as the published equation requires.
Figures this calculator will never guess for you
- No industry delivery rate, productivity figure, defect rate or cost per line is inserted.
- No optional component is filled in on the user's behalf.
Limitations
- COCOMO II is a calibrated estimation model, not an exact prediction; its published accuracy is a range, not a point.
- Estimates are only as good as the size, scale factors and effort multipliers entered.
- Compression outside the published 75%–160% range is refused rather than extrapolated.
Source and version
- Standard or reference
- COCOMO II post-architecture model — University of Southern California, Center for Systems and Software Engineering (COCOMO II Model Definition Manual — post-architecture effort PM = A × Size^E × ΠEM with A = 2.94 and E = B + 0.01 × ΣSF (B = 0.91), and schedule TDEV = C × PM^(D + 0.2 × (E − B)) × SCED%/100 with C = 3.67 and D = 0.28.)
- Published source
- University of Southern California, Center for Systems and Software Engineering — COCOMO II.2000
- Formula version
- Version 1
- Verification
- Reviewed against the cited source on
- How much weight the source carries
- Academic
- Applies to
- Currency
- The result is a ratio or index, so it does not depend on currency.
Cite this page
Free Calculator. (2026, September 16). COCOMO II Schedule Calculator. https://freecalculator.tech/tools/cocomo-ii-schedule-calculator
"COCOMO II Schedule Calculator." Free Calculator, 16 Sept. 2026, https://freecalculator.tech/tools/cocomo-ii-schedule-calculator.
COCOMO II Schedule Calculator — Free Calculator, https://freecalculator.tech/tools/cocomo-ii-schedule-calculator
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