You are 43% done. When does the project actually finish?

Real projects do not progress in a straight line; they ramp up, cruise, and crawl to the finish. Feed in your progress so far and the S-curve fits that natural shape and extends it to 100%, so your finish date accounts for the slow tail everyone underestimates.

Work Intermediate S-Curve Pro engine

After you install, this is the model to open.

Will the Project Finish on Time?

  1. In your spreadsheet, click the Sortia icon in the strip of icons down the right-hand edge. No strip? Click the arrow at the bottom-right to open it. You can also use Extensions, then Sortia, then Open Sortia.
  2. Click Start from a template and put that name in the search box.
  3. Pick the card with that name and click Load this template. It arrives on a new tab with real numbers already in it.

This one runs on a Pro engine, and every free install includes five full-quality runs on your own numbers, shared across all five Pro engines rather than five for each. After that, Pro is $199/year.

The answer

Extending your trajectory to 100%:

Done so far
43%
S-curve finish
Sep 21
Straight-line guess
~late Aug
The tail costs
~3 wks

A naive straight line says late August; the S-curve, which knows the finish slows down, forecasts September 21, about three weeks later. That gap is exactly the crunch that blindsides projects. Turn on "show all three curves" to bracket the date with an optimistic and pessimistic path. Paste in your own progress history.

The model

Six weeks of progress on a project that is 43% done. The S-curve fits the slow-fast-slow trajectory and projects it to completion.

Progress tracked6 weeks
Complete so far43%
CurveS-shaped (slow-fast-slow)
Forecastextends to 100%

Once it is in your sheet

  1. The model arrives with real numbers in it and runs as it stands, so you can press the button first and understand it second.
  2. Change the numbers to yours. The sheet marks which cells are inputs and which hold formulas, and most labels carry a note explaining the row.
  3. Press the run button at the bottom of the panel. It is labeled for the tool you are in, and the result lands on its own tab, with a written reading of it beside the figures.

Never used Google Sheets? Start here goes the whole way, in seven steps, and assumes nothing.