excel Archives - Kind of Lost

Resource Loading: The Chart Under the Gantt Chart

A resource loading chart is the histogram that sits under a Gantt chart: for each day of the plan, how many people that day needs. It is the least glamorous drawing in project management and the only one that ever told me anything I did not already know from looking at the bars.

Here is one for a 21-task house renovation, before and after the schedule was made to fit inside the crew that actually exists. The two panels hold exactly the same amount of work.

Two resource loading charts of the same renovation: before leveling the daily crew count peaks at 5 and exceeds the cap of 3 on 14 days; after leveling it never exceeds 3. — Same 155 crew-days under both panels. Leveling changes the shape of the histogram, not its area.

A Critical Path Method Template That Does Both Passes

Most of what gets offered as a critical path method template is a Gantt chart with a column called Start that you fill in yourself. That is not the critical path method. The whole point of CPM is that you never type a date — you type durations and predecessors, and the dates are computed. If the template makes you enter the start, it has quietly handed the work back to you and kept the chart.

So this is what an honest one has to do, which half of it a spreadsheet handles well, which half it fights you on, and the file I ended up with. Numbers throughout come from the same 21-task renovation plan the template ships with.

Table of early start, early finish, late start, late finish and total float for 21 tasks, with the zero-float critical path rows shaded. — What the method actually produces. Four dates and a float per task; the shaded rows are the critical path.

A Construction Schedule Template That Counts Crew

Download any free construction schedule template and you get the same thing: a task list, durations, start and finish dates, and a bar chart. What you almost never get is a column for how many people each task needs, and a row underneath that adds them up. Which is odd, because on a real job the binding constraint is rarely the calendar. It is that there are three electricians.

I built one with that row in it. It is free, it is a normal Excel file, and this is what the extra column changes.

Gantt Chart in Google Sheets: What Actually Ports

I built a scheduling template for Excel and then did the thing everybody does, which is open it in Google Sheets to see what survived. Most of a Gantt chart in Google Sheets works exactly as it does in Excel — the date maths, the lookups, the bars. One design decision in the file exists specifically because of what does not survive a trip between spreadsheet programs, and it is worth explaining, because it is the kind of thing that fails quietly rather than loudly.

This is the Google Sheets half of the template I wrote about when I built the Excel version. Same file, same six tabs — you can download the Excel version or copy the Google Sheets version, whichever saves you a step.

Bar chart of how many working days each task moves when the schedule is solved against a real crew limit. Eleven of twenty-one tasks move, by three to fourteen days; ten do not move at all. — Eleven of twenty-one tasks move once the crew limit is real. If the file arrives with every task reading as pinned, this chart comes back empty and the tool still reports success.

Gantt Chart in Excel: The Part Templates Leave Out

Every tutorial on building a Gantt chart in Excel stops in the same place. You end up with a task list, a Start column, a Days column, and a conditional-formatting rule that paints a bar across a grid of dates. It looks like a schedule. It is a picture of dates you typed in yourself, and it will keep looking correct long after it has stopped being true.

I spent a weekend building the version I actually wanted — one where Start is calculated, weekends are skipped, and a row underneath tells me how many people the plan is quietly assuming I have. Here is what went into it and where the spreadsheet honestly runs out of road.

Gantt chart of a 21-task renovation with a crew load row underneath. Every task bar is within capacity on its own, but the daily total for the general crew peaks at five people against a crew of three, and is over capacity on 14 days. — Nothing is over-allocated task by task. The plan just quietly assumes five people for fourteen days.