Business software · 5 min read
Why nobody can give you a straight price for custom software
What really drives custom software development cost, and how to make quotes from different agencies comparable.
The short answer
There's no reliable single price for custom software development in the UK without a defined scope. Cost depends on business rules, user permissions, integrations, data migration and the level of testing and support required. Ask suppliers to price the same small first release and to separate one-off setup costs from ongoing running costs.
By Raja Wahab, Co-founder, Fixby Studios · Published · Updated · 5 min read
Why a headline price isn't enough
A customer portal that just shows documents is a very different project from one that calculates prices, takes payments and manages approval permissions across several companies. Both might be described as 'a simple portal'. Screen count alone doesn't capture the real work involved.
Fixby's website package prices are fixed because websites are a defined product. Bespoke business software needs an assessment of the actual workflow and its dependencies, so this guide won't publish a fabricated market average for custom software development cost in the UK.
The main cost drivers
| Driver | Question to answer before quoting |
|---|---|
| Business rules | What happens on rejection, cancellation or a correction? |
| Access | Which records can each user read or change? |
| Integrations | Do the existing tools actually support the operations you need? |
| Migration | How clean is the data and how much history must move? |
| Reliability | What must still work during an outage? |
| Handover | Who operates and maintains the finished system? |
Simple document portal
- — Shows records only
- — Few permission rules
- — Cheaper to build
Portal with payments and approvals
- — Calculates prices
- — Multiple companies and permissions
- — Costs far more
Build a comparable quote request
Give each supplier the same process description, sample data, user roles and acceptance criteria. Ask them to list their assumptions, exclusions and any third-party charges. A supplier who flags uncertainty is usually giving you a more honest quote than one who hides it inside a single total.
Request a separate price for discovery if the workflow is unclear. Its output should be something usable: a mapped process, tested assumptions and a scoped first release, not just another sales presentation.
“Custom software development cost in the UK depends on scope, not a generic day rate.”
Model the first year and the following years
Use this structure: setup and migration, plus development and testing, plus staff training, plus annual hosting, licences and support. Keep optional enhancements separate so you can see the real cost of running the agreed version.
As a purely illustrative calculation, a £12,000 build plus £2,400 annual running costs totals £14,400 in year one and around £19,200 over three years before any further changes. These are example figures only, not Fixby prices or a market estimate.
If the quote is too high
Reduce the first release to one useful end-to-end process. Keep manual approval where automation isn't essential yet. Reuse existing tools where they already fit. Don't cut permissions, backup recovery or critical testing just to shrink the headline figure.
Sources
Your questions
- How much does custom software development cost in the UK?
- It depends entirely on scope: business rules, integrations, data migration and testing. There's no reliable average figure without a defined first release to price against.
- What should a custom software quote include?
- Setup and development costs, plus ongoing hosting, maintenance and support, with assumptions and exclusions listed clearly so you can compare suppliers fairly.
- Can I get a fixed price for custom software?
- Yes, for a clearly scoped first release. Open-ended requirements usually need a discovery phase first to reduce the risk of the price changing later.
- Why do custom software quotes vary so much?
- Suppliers often assume different scopes for the same brief. Giving everyone the same process, sample data and acceptance criteria makes quotes genuinely comparable.
Raja Wahab is co-founder of Fixby Studios, a Huddersfield studio building websites, SEO, social media and business software for small, owner-managed businesses across West Yorkshire.
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