Software Development Cost Calculator
Cost a build including tools, overhead and a contingency reserve.
What this calculator does
Cost accumulation over an effort estimate. Every component is entered by the user, and optional components left at zero are excluded from the total.
Inputs and what they mean
- Currency
- — Amounts are shown in the currency you pick. No exchange rate is applied..
- Estimated effort
- — Person-months from your sizing model..
- Loaded cost of one person-month
- — number value.
- Tools and licences (optional)
- — Optional component. Leave at 0 to exclude it from the result..
- Infrastructure and environments (optional)
- — Optional component. Leave at 0 to exclude it from the result..
- Overhead applied to labour (optional)
- — Optional component. Leave at 0 to exclude it from the result..
- Contingency reserve (optional)
- — Optional component. Leave at 0 to exclude it from the result..
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
Labour = Effort × Loaded cost per person-month; Base = Labour × (1 + Overhead rate) + Tools + Infrastructure; Total = Base × (1 + Contingency rate)
Worked example
286 person-months with tools and a reserve
Optional components left at zero are excluded, not guessed.
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
Results depend entirely on the figures you enter and are rounded for display. They are for general information and education, not professional advice.
Reference: University of Southern California, Center for Systems and Software Engineering — COCOMO II model definition manual
Last reviewed:
Common questions
Formula, source and verification
Effort is costed at the organisation's own person-month cost, then optional components, overhead and contingency are added.
The question it answers: What does this build cost once tools, environments, overhead and a reserve are counted?
The formula
Labour = Effort × Loaded cost per person-month; Base = Labour × (1 + Overhead rate) + Tools + Infrastructure; Total = Base × (1 + Contingency rate)
- PM — Estimated effort
- (person-months). Effort from the organisation's sizing model.
- c — Loaded cost of one person-month
- (currency). Employer cost of one person-month.
- T — Tools and licences
- (currency). Optional.
- I — Infrastructure and environments
- (currency). Optional.
- o — Overhead rate
- (%). Optional overhead applied to labour, using the organisation's own allocation.
- g — Contingency rate
- (%). Optional reserve for identified risk.
Units: Person-months; currency; percentages.
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
Cost accumulation over an effort estimate. Every component is entered by the user, and optional components left at zero are excluded from the total.
Assumptions built into the result
- Mathematical: All components cover the same scope and period as the effort estimate.
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.
- No default overhead or contingency percentage is applied.
Limitations
- Gives a cost, not a price.
- Inherits the uncertainty of the effort estimate it is given.
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
- Amounts stay in the currency you choose; no exchange rate is applied.
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