Spreadsheets to MRP: How Long Does the Move Take?

The move from spreadsheets to MRP software is rarely held up by the software. It is held up by data. Buying the system, setting it up and training the team are predictable pieces of work. Finding out that your part numbers mean three different things, that two BOMs disagree about the same assembly, or that nobody has updated a supplier lead time since the last person left the business, is what stretches a project out.

So the honest answer to how long the move takes is that the data preparation phase sets the pace. Everything else can be planned around it.

What the move actually involves

A spreadsheets to MRP transition is not one event. It breaks down into a handful of stages: agreeing what data you are taking with you, cleaning it, mapping it into the structure the MRP platform expects, testing it with real products, training people on the new way of working, and then going live with support in place afterwards. Only one of those stages involves the software vendor. The rest is your business deciding what its own records actually say.

Why spreadsheets get you this far and then stop

Most spreadsheet based planning setups carry the same handful of components: bills of materials, stock level tracking, demand planning sheets and purchase planning tabs. For a small operation with a short product list and a stable customer base, that combination is flexible, familiar and cheap to run.

The trouble starts when the operation becomes more complex than the file can hold. That tipping point tends to announce itself through symptoms rather than a single dramatic failure: stockouts on items you thought you had, excess inventory on items you did not need, missed delivery dates, and a growing amount of time spent checking whether the spreadsheet is right. Once people are reconciling the planning file instead of trusting it, the spreadsheet has stopped being a planning tool and become a source of errors and delays.

Step one: decide what you are taking with you

Before any cleaning work starts, agree the scope of the migration. Splitting your records into two groups makes this much easier.

Master data comes first

This is the information the MRP system needs in order to plan anything at all: your item and part records, bills of materials, supplier records, customer records, lead times and units of measure. If master data is wrong, every calculation built on top of it is wrong too, which is why it deserves the most attention and the most time.

History is usually optional

Teams often assume every historical transaction has to come across. In practice, most migrations need opening balances and accurate current stock rather than a full archive of past orders. Deciding early what history genuinely needs to move, and what can simply be kept as a read only copy for reference, removes a large amount of work from the project.

Step two: clean the data before anyone converts it

Cleaning is the part that decides your timeline. The work is unglamorous and it cannot be rushed, because every problem fixed now is a problem the business does not have to fix after go live.

The cleaning jobs that take the longest

• Duplicate records for the same item, supplier or customer, often created because two people set them up at different times.
• Part numbers that follow no consistent pattern, so similar items cannot be grouped or searched reliably.
• Units of measure that are ambiguous, such as quantities recorded in both single units and packs without a clear rule.
• Bills of materials that have drifted out of line with what is actually built on the shop floor.
• Lead times that were set years ago and have never been reviewed.
• Blank or inconsistent fields, particularly around item descriptions and categorisation.

Work through these methodically and record the decisions you make. A short written rule for how part numbers are formatted, or how units of measure are expressed, saves an enormous amount of confusion later.

Step three: validate before you upload

Validation is what stops a clean looking file becoming a messy live system. Build a small test set of real products and run it through the platform before you commit anything.

1. Choose a handful of representative items, ideally including one with a multi level bill of materials.
2. Load them into the MRP system as a trial rather than a live migration.
3. Compare what the system calculates against what your spreadsheet says, and investigate every difference rather than assuming the system is wrong.
4. Check that stock levels, lead times and supplier details have landed where you expected them.
5. Repeat with a second batch covering a different part of the business, such as a purchased item rather than a manufactured one.

Differences that appear at this stage are useful. They show you where the spreadsheet was papering over an inconsistency. Differences that appear after go live are expensive.

Running the old and new systems side by side

Most manufacturers keep the spreadsheet available during the early weeks, read only, so people can check figures while they build confidence in the new system. That is sensible, provided you set a clear cut over point and a clear rule about which system is the source of truth. Parallel running that has no end date simply doubles the work and undermines the reason for moving in the first place.

What slows a spreadsheets to MRP move down

Projects rarely slip because of the platform. They slip because the data clean up was underestimated, because no single person owned the decisions about how records should be standardised, or because a key member of staff held a lot of product knowledge that had never been written down. Naming one owner for the data work and giving them time to do it is the simplest thing you can do to keep the project moving.

If you would rather not work it out alone, an experienced implementation partner can help you scope the migration, run the validation and make the calls on the awkward records before they reach the live system. The earlier that help arrives, the less unpicking there is to do later.

Frequently Asked Questions

Can we run spreadsheets and MRP side by side during the switch?

Yes, and most manufacturers do. Keep the spreadsheet as a read only reference rather than a second planning tool, and agree in advance which system is the source of truth. Set an end date for the parallel period so the business commits to the new way of working instead of quietly drifting back to Excel.

How much historical data should we migrate?

Usually far less than people expect. Most migrations need accurate current stock levels and opening balances rather than a full archive of past transactions. Agree the scope early, keep older history available as a read only copy for reference, and you will remove a significant amount of unnecessary work from the project.

Do we need to fix every part number before go live?

Not every single one, but you should at least have a consistent rule and apply it to everything in active use. A written format for part numbers and units of measure prevents confusion afterwards. Items you barely touch can usually be tidied after go live, provided someone owns the task.

What is the biggest risk in a spreadsheets to MRP move?

Assuming the spreadsheet is correct. Files that have been edited by several people over several years often contain duplicate records, drifting bills of materials and stale lead times. The validation stage exists to expose those differences while they are still cheap to fix, rather than after the system is live and staff are relying on it.

Who should own the data clean up?

One named person, not a committee. That person needs authority to decide how records are standardised and enough time to do the work properly. In many smaller manufacturers this sits with an operations or supply chain manager who already understands the products, supported by the people on the shop floor who know what is really built.