Software Project Schedule Calculator
Turn effort into a schedule, by the published model or by your staffing.
In short
Turn effort into a schedule, by the published model or by your staffing.
Formula: COCOMO II model: TDEV = 3.67 × PM^(0.28 + 0.2 × (E − 0.91)). Staffing model: Months = Effort in person-months ÷ People available
What this calculator does
The chosen model is applied on its own. The COCOMO II route uses the published constants; the staffing route is a straight division by available staff. The two are never averaged or blended.
Use it to turn Estimation model, Estimated effort, COCOMO II scale exponent, People available 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
- Estimation model
- — Two published methods, shown separately. They are never combined into one number..
- Estimated effort
- — Person-months from your sizing model..
- COCOMO II scale exponent
- — 0.91 + 0.01 × the sum of your five scale factors. 1.0997 is the published nominal value..
- People available
- — Used by the staffing method..
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
COCOMO II model: TDEV = 3.67 × PM^(0.28 + 0.2 × (E − 0.91)). Staffing model: Months = Effort in person-months ÷ People available.
Inputs used: Estimation model, Estimated effort, COCOMO II scale exponent, People available.
Edge handling: Estimated effort is required.; Estimated effort cannot be negative.; Estimated effort must be no more than 1000000000.; COCOMO II scale exponent is required.; COCOMO II scale exponent must be greater than zero..
Worked example
286 person-months on the published schedule equation
- Start with Estimation model: cocomo, Estimated effort: 286, COCOMO II scale exponent: 1.0997, People available: 0.
- Apply the method: COCOMO II model: TDEV = 3.67 × PM^(0.28 + 0.2 × (E − 0.91)). Staffing model: Months = Effort in person-months ÷ People available.
- Pick the model you want; the other one is not mixed in.
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 software project 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?
Two published methods for turning effort into calendar time, selectable on the page and reported separately. 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. The staffing model ignores the compressibility limits the published model imposes.
How do I use the Software Project Schedule Calculator?
Enter the required values for Estimation model, Estimated effort, COCOMO II scale exponent, People available. 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 Software Project Schedule Calculator use?
COCOMO II model: TDEV = 3.67 × PM^(0.28 + 0.2 × (E − 0.91)). Staffing model: Months = Effort in person-months ÷ People available 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.
Can the Software Project 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
Two published methods for turning effort into calendar time, selectable on the page and reported separately.
The question it answers: Given this much effort, when can we realistically finish?
The formula
COCOMO II model: TDEV = 3.67 × PM^(0.28 + 0.2 × (E − 0.91)). Staffing model: Months = Effort in person-months ÷ People available
- PM — Estimated effort
- (person-months). Effort from the organisation's sizing model.
- E — COCOMO II scale exponent
- (exponent). 0.91 + 0.01 × the sum of the five scale factors; 1.0997 is the published nominal value.
- N — People available
- (people). Used by the staffing method only.
Units: Person-months; months; people.
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
The chosen model is applied on its own. The COCOMO II route uses the published constants; the staffing route is a straight division by available staff. The two are never averaged or blended.
Assumptions built into the result
- Mathematical: The effort estimate covers the whole scope being scheduled.
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.
- The two models are never combined into one number.
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.
- The staffing model ignores the compressibility limits the published model imposes.
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). Software Project Schedule Calculator. https://freecalculator.tech/tools/software-project-schedule-calculator
"Software Project Schedule Calculator." Free Calculator, 16 Sept. 2026, https://freecalculator.tech/tools/software-project-schedule-calculator.
Software Project Schedule Calculator — Free Calculator, https://freecalculator.tech/tools/software-project-schedule-calculator
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