Software Team Size Calculator
Find the average team size an effort and schedule imply.
In short
Find the average team size an effort and schedule imply.
Formula: Average staff = Effort in person-months ÷ Schedule in calendar months
What this calculator does
Effort divided by schedule, exactly as the published model relates the two. No staffing curve or ramp-up profile is assumed.
Use it to turn Estimated effort, Planned schedule 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
- Estimated effort
- — Person-months from your sizing model..
- Planned schedule
- — Calendar months the work has..
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
Average staff = Effort in person-months ÷ Schedule in calendar months.
Inputs used: Estimated effort, Planned schedule.
Edge handling: Estimated effort is required.; Estimated effort cannot be negative.; Estimated effort must be no more than 1000000000.; Planned schedule is required.; Planned schedule cannot be negative..
Worked example
286 person-months over 22 months
- Start with Estimated effort: 286, Planned schedule: 22.
- Apply the method: Average staff = Effort in person-months ÷ Schedule in calendar months.
- The published staffing relation: average staff is effort divided by schedule.
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 team size 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 staffing relation between effort and schedule. Check the formula, example, and limitations on this page before using the result for a real professional & industry decision.
What are its limits?
An average; real projects staff up and down over time. Says nothing about whether that team size is feasible.
How do I use the Software Team Size Calculator?
Enter the required values for Estimated effort, Planned schedule. 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 Team Size Calculator use?
Average staff = Effort in person-months ÷ Schedule in calendar months 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 Software Team Size 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 staffing relation between effort and schedule.
The question it answers: How many people do we need on average to finish in the time we have?
The formula
Average staff = Effort in person-months ÷ Schedule in calendar months
- PM — Estimated effort
- (person-months). Effort from the organisation's sizing model.
- TDEV — Planned schedule
- (months). Calendar months the work has.
Units: Person-months; months; people.
What kind of calculation this is
Deterministic formula. The same inputs always give the same answer. The maths is fixed and does not depend on judgement.
Method
Effort divided by schedule, exactly as the published model relates the two. No staffing curve or ramp-up profile is assumed.
Assumptions built into the result
- Mathematical: Staffing is treated as an average across the schedule, not as a ramp.
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
- An average; real projects staff up and down over time.
- Says nothing about whether that team size is feasible.
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 Team Size Calculator. https://freecalculator.tech/tools/software-team-size-calculator
"Software Team Size Calculator." Free Calculator, 16 Sept. 2026, https://freecalculator.tech/tools/software-team-size-calculator.
Software Team Size Calculator — Free Calculator, https://freecalculator.tech/tools/software-team-size-calculator
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