Completion Forecast Calculator
Calculate Completion Forecast step by step: Periods remaining = (total − done) ÷ (done ÷ periods elapsed − scope added per period).
In short
Formula: Periods remaining = (total − done) ÷ (done ÷ periods elapsed − scope added per period).
What this calculator does
Calculate Completion Forecast step by step: Periods remaining = (total − done) ÷ (done ÷ periods elapsed − scope added per period). Worked example, questions and limitations included.
Use it to turn Total work, Work completed, Periods elapsed, Average scope added per period 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 project estimation calculation.
Inputs and what they mean
- Total work
- — number value.
- Work completed
- — number value.
- Periods elapsed
- — number value.
- Average scope added per period
- — Enter 0 if scope is fixed..
How to use it
- Enter each value in the unit shown next to the box (use the unit converter first if your numbers are in other units).
- Check the breakdown to see every intermediate step.
- Read the limitations before relying on the result.
Formula
Burn-down extrapolation using the average completion rate so far.
Scope growth is subtracted, so a project that keeps growing never finishes on paper — which is the honest answer.
Units can be tasks, story points, drawings or any consistent measure.
Periods remaining = (total − done) ÷ (done ÷ periods elapsed − scope added per period).
Inputs used: Total work, Work completed, Periods elapsed, Average scope added per period.
Worked example
120 of 300 tasks in 6 weeks
- Rate = 20/week; net = 15/week.
- Remaining = 180 ÷ 15 = 12 weeks.
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
- Linear extrapolation.
- Assumes stable team and work size.
- No confidence range; see the release forecast calculator for ranges.
- Results are planning estimates built only from the figures you enter. They are not a guarantee of cost, schedule or delivery, and they do not replace your organisation's own project controls.
- The result depends on the values you enter for this completion forecast calculator; it does not supply missing rates, rules, prices, dates, or assumptions for you.
Common questions
Should I use recent or overall rate?
Overall is steadier; recent reflects changes. Try both by changing the inputs.
Why include scope growth?
Ignoring it makes forecasts optimistic; most projects add work as they go. Check the formula, example, and limitations on this page before using the result for a real project estimation decision.
Is this a date?
It gives periods. Count forward on your calendar, allowing for holidays.
How do I use the Completion Forecast Calculator?
Enter the required values for Total work, Work completed, Periods elapsed, Average scope added per period. 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 Completion Forecast Calculator use?
Periods remaining = (total − done) ÷ (done ÷ periods elapsed − scope added per period). 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 Completion Forecast 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.
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