Moving from Dynamics NAV to Dynamics 365 Business Central – Part 5: Budget and Timeline

By Sean Solberg | June 17, 2020

NAV to BC - Budget and Timeline

The previous four posts have hopefully helped shape your vision of the project scope. At this point, if not earlier, you have probably thought past how your new home will look and how you will get all of your stuff there. You are now concerned with how much this will all cost and how long it will take to execute. Moving is never free after all.

If you skipped straight to this entry, the analogy here may not make sense and you could have some difficulties using the tool. If this is the case, it would be recommended to first the initial installment in this series – if not all four.

Moving from Dynamics NAV to Dynamics 365 Business Central series:

Estimating Art Balanced with Partnership Trust

To start, a confession is in order. All upgrade and reimplementation project estimates are imperfect. A moderate component of any approach includes some subjectivity and speculation. Anyone who tells you otherwise is either a fortune teller or misleading you (or themselves).

The two offsets to this are flexibility in the project and a strong relationship. We sometimes reference “horse-trading” within a project, but it really represents some amount of flexibility in the estimate, smaller scope items, and the ability to appreciate that both sides of the project are acting in each other’s best interests. This, combined with scoping and planning the project responsibly at the start, will limit the small, inevitable, surprises from impacting the overall success.

Put another way, your movers have assumptions about distance and volume and the general contractors have some assumptions about what they’ll find when they get into your new home. Additionally, you have not talked to the utilities or other service providers in the area at this point.

If you have good partnerships with the movers and general contractor and have worked with them before, then you can start to feel a little easier about how it will go when surprises do arise.

Back of the Napkin Approach

With all of that out of the way, let’s try to apply some napkin math to the project. This is the discussion where you and your partner are sitting at lunch and you ask how much it will cost. And where they might choke on their sandwich while formulating an answer.

The table below represents a tool allowing you to measure your project scope on a scale of 1 to 100. For each of the six variables, you will rank the area with a value of 0 to 10. Then, on each line, multiply that measure against the weight for the category – getting you a weighted result for the category. Finally, add the six weighted results together. Most should find themselves in the 9-24 range when they’re all done. It’s not perfect but it is a pretty good starting point for discussion.


Think about the volume of objects (tables, pages, etc…) you have modified or added to your current version of NAV and how many of those you will carry to BC. All objects are not created equal and all modifications are not created equal. As such, we have a better tool we use for this step, but just assume every 50 objects adds 1 to the project measure for now.

ISVs and Integrations

These are also a little nuanced, but just assume that each third-party application that you will carry to BC, or integrate with BC, adds a measure of 1. You can exclude small impact solutions that touch only one or two tables.

Data Migration

This is more straight-forward. If you think you want to reimplement, start at 1, assuming you will only be carrying forward master records (customers, vendors, etc…) and minimal open documents/balances. If you think you are going to keep all of your data via an upgrade, enter a 3 if you are moving from Role Tailored Client, or assign a 6 if you are coming from the classic client. This is napkin math – we can fine-tune this later for the specifics of your version and approach.

Data Cleanup and Mapping

This is based on the custom fields you are carrying forward and master table cleanups you wish to address. Assume a 1 in the measure column for every 50 custom fields you are carrying and another 1 for every few master tables (again, think customers, vendors, items here). Also, if you are going to restructure your chart of accounts or a specific dimension category, add 1 for each.

Workflows and Security

Add 1 to the measure for every few workflows you plan to reengineer, add 3 if you have jobs and are on version 5.X or prior, add 1 if you have manufacturing or service prior to version 5.X, and add 0 to 4 depending on the granularity of your security requirements (best guess, but we typically see a 1 or 2 here).

Other Variables

Finally, and most nuanced, we have the “other” category. This might be more difficult, and we can help you through this one later. For now, consider your last upgrade of NAV (if there was one) and rank the “headache” factor from 1 to 10. Then subtract 50% from that number. This is not a perfect parallel in best cases and can be worse than crude in other cases, but you will want some number here to start.

Dynamics NAV to D365 Business Central Top-Level Estimate Tool

Moving from dynamics nav to dynamics 365 business central – part 5: budget and timeline

Add them all up. If you are over 25, you may have a moderate-to-large project ahead of you, but we can help you consider ways to trim that back down. If you are under 8, you have a much smaller customization need and probably have a very clean path to BC. For everyone in-between 9 and 24, you are in good company. This is where we typically find a mature NAV installation with a relatively aggressive approach to minimizing customizations and no overriding industry-specific need causing suites of functionality to be added.

For budget purposes, multiple your resulting number by 100. This is the starting point for hours, from which you and your partner can work the actual estimate downward. As an example, you come up with a score of 15, resulting in 1500 hours. Deep breaths – this is the starting point. This number will likely shrink as you talk through the options with your partner.

Finally, your timeline will be a function of those hours and the freedom of your core NAV team to participate in the project. If the project is ultimately 1000 hours, assume 6-8 months as a potential timeline. This will allow breathing room for your group as well as a couple resources from your partner’s side to be primarily dedicated. As the numbers go up, the timeline is somewhat linear.

Give the tool a shot, talk to your partner, and then start to plan your move. You’re going to like your new home once you arrive.

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