Planning in Excel: when does it stop working?

What a schedule in Excel usually looks like

A schedule in Excel almost always has the same structure, whether it was built in-house or started as a planning template from the internet:

• An order list: order number, customer, article, quantity, requested delivery date and status.
• A weekly overview with the planned hours per day or per week, often as coloured cells that together form a kind of Gantt bar.
• A tab per machine or department, with blocks that are filled in and moved by hand.
• Formulas that add up the planned hours and compare them with the available hours, and conditional formatting that turns a week red when it is too full.
• A notes column for everything that does not fit the structure: waiting for material, rush, customer will call back.

Where it works well

For one machine or one department, with a manageable flow of orders and one planner who oversees everything, Excel is fine. It is flexible, costs nothing extra and you can set the schedule up exactly the way you want. As long as the schedule fits in one head and one sheet, there is little reason to change.

Where an Excel schedule breaks down

The problems rarely arrive all at once; they creep in as the business grows:

• Multiple machines. As soon as an order passes more than one machine, one operation depends on another. Excel does not know that milling can only start once sawing is done; that lives only in the planner's head.
• Capacity. A sum of hours per week does not tell you whether the work actually fits. Shifts, maintenance, setup times and work already running all count, and a week below 100 % can still mean an order is late.
• Rush orders. One rush order in between means everything behind it shifts. In Excel that is manual work: moving blocks, checking what is now late and hoping nothing was missed.
• One person. Often only one person can really read and change the schedule. When they are ill or on holiday, planning stops or runs on gut feeling.
• Versions. A copy on the shared drive, a printout on the wall, a version in the mail: which one is right? Two people editing at once overwrite each other's work.
• No feedback from the shop floor. What has actually been made only reaches the sheet when someone updates it. So the schedule always lags behind reality.

Checklist: time to switch?

If you recognise several of these points, it is worth looking at an alternative to the Excel schedule:

• You cannot tell a customer straight away when a new order can be ready.
• Orders pass more than one machine or department.
• Fitting in a rush order takes more than a few minutes.
• Only one person really understands the schedule.
• Several versions of the schedule are in circulation.
• The shop floor keeps its own lists next to the schedule.
• A late delivery only shows up once it is already late.
• Orders are retyped by hand from e-mail or PDF into the sheet.

Excel does not have to go entirely

Excel stays useful for analysis, reports and a quick export. The difference is that the schedule itself no longer lives in the sheet, but in a system that knows the rules. If you want, you can still export the schedule to Excel afterwards.

The next step: a planning board with finite capacity

The alternative is not a bigger spreadsheet, but a schedule that calculates. A planning board with finite capacity knows your machines, shifts and routings, and schedules only what actually fits next to the work already planned. The delivery date follows from that, and the bottleneck is visible before you confirm an order.

You put a rush order in between and see straight away which orders move because of it. Everyone looks at the same schedule, and the shop floor reports what is finished, so the schedule keeps up.

It does not have to be a large package. I build such a schedule as custom software, around your own machines and order flow and connected to the ERP you already use. How that schedule calculates is explained step by step in the production planning explainer. In the demo (in Dutch, fictional data) a purchase order lands on the machines in about 90 seconds.

Frequently asked questions

Is there a good Excel planning template for production?

For one machine and a manageable flow of orders, a simple template is enough: an order list, a weekly overview and a sum of hours per week. Once orders pass several machines, no template keeps track of the sequence and the capacity for you; then you need a schedule that calculates.

What is finite capacity scheduling?

Scheduling with the capacity that actually exists: only planning what the machines can run in their shifts, next to the work already planned. The delivery date then follows from the schedule instead of being estimated.

Can my existing Excel schedule be the starting point?

Yes. The structure of your sheet, such as the order list, the machines and the operations, shows how you plan today. In a free 30-minute introductory call I look at your schedule with you, and you hear honestly whether custom software makes sense for you.