How a Power Apps build works, and what it costs.
Four steps. A free call, a paid Review that produces a fixed quote, a fixed-price build, and optional support afterwards. This is Power Apps development cost in the UK as Castlane charges it: you know the scope and the price before anything starts, and nothing is added to the bill that was not agreed.
The four steps
1 · Call
30 minutes, free
You tell me what the spreadsheet does, who depends on it and what breaks when it fails. I tell you whether a system is worth your money, and if it is not, I say so. If the scope is already clear from the call, we skip the Review and go straight to a fixed quote.
No preparation needed. Having the file open helps.
Usually within the week
2 · Review
£450, one week
I look at the actual files and the way your team uses them. At the end of the week you get four things in writing:
- A map of the process the spreadsheet runs, and who touches it.
- What to keep, what to rebuild, and what to leave alone.
- A licensing assessment against the Microsoft 365 you already have.
- A fixed-price proposal for the build, with a timescale.
The £450 comes off the build price in full if the build starts within 60 days. If you decide not to go ahead, you keep the document and owe nothing more.
Credited against the build
3 · Build
Excel from £900 · applications from £3,000
The build happens in your own Microsoft 365, in an environment set up for your business, with security roles so people see what they should. It is tested on your real data before you touch it, documented, and handed over with training for the people who will use it.
Most applications land between £5,000 and £12,000 over four to ten weeks. Excel systems take two to three weeks. Anything added after the scope is agreed is quoted separately, so the price does not drift and the deadline does not slip.
It is your system. You are not renting it from me and you are not locked in.
Two to ten weeks
4 · Support
£250 a month, optional
Up to three hours a month of fixes, small changes and new reports, with a reply within two working days. Time is logged and shown to you each month; unused hours do not carry over. A new module or a change of scope is quoted separately. Cancel any month.
Optional. A finished system needs very little once it is live, and you can add support later or ask for a one-off quote when something comes up.
Rolling
Built in your own Microsoft 365. What that means.
- Your tenant. The system lives in the Microsoft 365 account your business already has, not on my servers.
- Your environment. I set up a Power Platform environment for your business, separate from anything else, with a test copy for changes.
- Your licences. The Review tells you exactly which licences the build needs, and whether you already hold them. Many businesses on Microsoft 365 Business plans need one Power Apps licence per user; some need none. It is assessed per build, never assumed.
- Your data. It stays in your tenant, under your security roles. I am given access for the build and removed afterwards unless you keep support.
- Your system. You get the solution files, the documentation and the training. Another developer could pick it up tomorrow.
Questions people ask before the call
How much does a Power Apps build cost?
Applications start at £3,000 and most land between £5,000 and £12,000, quoted as a fixed price after a one-week Review. Excel systems start at £900.
Why is the Review paid when the call is free?
The call is a conversation; the Review is a week of work on your actual files that ends in a written recommendation and a fixed quote you can take elsewhere. The £450 is credited in full against a build that starts within 60 days.
Can I skip the Review?
Yes, when the scope is clear from the call. Small, well-defined builds and Excel systems usually go straight to a quote.
Can’t I just fix the spreadsheet?
Sometimes, and if so I will say on the call. A shared workbook rarely has permissions, an audit trail or a single version, and if the person who built it leaves, the process leaves with them. Those are the problems a system solves.
What happens if I want something added halfway through?
It is quoted separately and built after the agreed scope, so the price and the deadline you signed up to do not move.
More questions? The full list is here, or ask on the call.