Bottom line: Moving from Sage 200 to cloud ERP takes 6–14 months, costs 40–60% more than the quote you were given, and will break at least three processes you assumed were standard. None of that means you shouldn’t do it. It means you should budget for the reality, not the sales deck.
The Quote vs The Bill
Every ERP vendor will give you a number. That number is wrong. Not because they are lying — though some are being economical with the truth — but because the number they quote covers the software and a best-case implementation. It does not cover the 14 other things that will actually determine whether this project succeeds or quietly becomes the thing nobody talks about at board meetings.
I have spoken to finance directors at over a dozen UK mid-market companies who have made this move in the past two years. The pattern is consistent enough to chart.
Where the Unquoted Costs Actually Land
Hidden cost categories in UK mid-market ERP migrations, averaged across 14 projects. Data cleansing consistently ranks highest.
Source: CTC analysis of 14 UK mid-market ERP migration projects, 2024–2025
Data cleansing is the one that catches everyone. You assume your Sage 200 data is clean because you have been running reports off it for years. Then you try to import it into Sage Intacct or NetSuite and discover that your chart of accounts has 340 nominal codes, 87 of which have not been used since 2019, and your customer records contain four different spellings of Tesco.
The Timeline Nobody Believes
The sales team will tell you 12 weeks. Your implementation partner will say 16–20 weeks. The actual elapsed time, from signing the contract to the point where your finance team stops keeping the old Sage 200 system running “just in case”, is typically 9–14 months.
Here is how the timeline tends to unfold in practice, tracked against what the original project plan said.
ERP Migration: What They Said vs What Happened
Planned vs actual project completion percentage over 12 months. The gap opens at month three when data cleansing reveals hidden complexity.
Source: CTC composite of 8 UK mid-market Sage 200 migration timelines, 2024–2025
The gap opens at month three. That is when data cleansing starts revealing problems, and when your team realises that the “standard” processes they run in Sage 200 are actually held together by three macros that Dave in accounts built in 2017.
Where the Budget Actually Goes
If you ask most finance directors where they expected the money to go versus where it actually went, you get a remarkably consistent picture. The software licence cost is roughly what they expected. Everything else is not.
Typical Mid-Market ERP Migration: Actual Budget Breakdown
How the total migration budget breaks down in practice. Software licences account for less than a third of total spend.
Source: CTC survey of 14 UK mid-market FDs, 2025
Sage Intacct vs Xero vs Staying on Sage 200
The most common paths for a UK mid-market company leaving Sage 200 are Sage Intacct (Sage’s own cloud offering), Xero (if you are on the smaller end of mid-market), or Oracle NetSuite (if your revenue is above £20m and you want to hate yourself for 18 months).
Sage Intacct fits companies at £5m–£50m revenue, with strong multi-entity and native MTD compliance at £300–£500 per user per month. Xero works well for £1m–£10m revenue at £42–£59 per month, but struggles with complex reporting and multi-entity. Staying on Sage 200 remains an option if your current pain is tolerable — the question is whether that stays true as MTD requirements expand and your implementation partner eventually stops supporting your version.
The Change Management Problem
Here is the thing that nobody puts in the project plan: your finance team does not want to do this. They have spent years building muscle memory around Sage 200. They know where every button is. They know which reports to run on the third working day of each month. They know that you have to click “Post” twice on the purchase ledger because of that bug that never got fixed.
Moving them to a cloud system is not a technology project. It is a people project that happens to involve technology. Budget for training, budget for parallel running, and budget for the three months of productivity dip where everything takes twice as long because nobody can find the VAT return.
The Checklist I Wish I’d Had
Audit your chart of accounts — delete every nominal code not used in the past 18 months
Map every custom report, macro, and spreadsheet that depends on Sage 200 data
Confirm MTD compliance will be maintained throughout — test the bridging software
Test Companies House iXBRL filing from the new platform before you commit
Budget 30% contingency on top of the quoted implementation cost
Plan for 3 months of parallel running (both systems live)
Identify your “Dave” — the person who built all the workarounds — and get them involved early
Get written confirmation of data migration scope from the implementation partner
Negotiate a fixed-fee data cleansing phase, not time-and-materials
Set a hard date for switching off the old system — or you never will
