✦ Sales assets
What does custom software cost? A real breakdown
What does custom software cost? Anyone who gives you a figure before understanding your process is guessing. What we can tell you honestly is what drives the number up or down, and how to compare two quotes that use different assumptions.
Haystak · 11 August 2026 · Updated 11 August 2026 · 8 min read
What does custom software cost is the first question every prospect asks, and the honest answer is: it depends on scope, integrations, data volume and how finished the design is before anyone writes code. A brochure site with a contact form and a multi-user scheduling platform with three integrations are both 'custom software', at wildly different prices.
Rather than give you a number that means nothing without context, this post breaks down the variables that move the price, in the order they usually matter, so you can price-check any quote you're given against something real.
The variables that actually move the price
| Driver | Why it matters |
|---|---|
| Number of distinct user roles | Each role usually means different screens, permissions and logic to build and test |
| Integrations with existing systems | Every external system is another API to learn, another failure mode to handle |
| Data migration from a legacy system | Old data is rarely clean; cleaning and mapping it is its own project |
| How settled the requirements are | Requirements that change mid-build cost more than the same change agreed upfront - see our brief guide |
| Compliance or audit requirements | Record-keeping, approvals and traceability all add build and testing time |
| Uptime and support expectations | 24/7 support and guaranteed response times cost more to resource than office-hours support |
Two businesses can describe the 'same' project and get very different quotes because one has three user roles and a single system to integrate, and the other has nine roles and a legacy database nobody at the company fully understands any more.
The shape of the commercial model, not the number
We don't publish day rates or project totals here, because a figure with no scope attached is meaningless and often misleading. What's useful is understanding the shape of how a quote is usually built:
- Discovery or scoping, usually a small fixed fee, that produces a written specification you can take to any supplier - see how to write a software brief for what that document should contain.
- Build, priced either fixed against the specification or as day-rate/time-and-materials, each with trade-offs - covered in fixed price vs day rate.
- Hosting and infrastructure, an ongoing running cost independent of who built the software.
- Support and maintenance, usually a monthly retainer or a rate for ad-hoc fixes, separate from the build.
A worked comparison, without the figures
Fill this in with the two quotes in front of you. It surfaces the real difference faster than the bottom line does.
| Line item | Quote A | Quote B |
|---|---|---|
| User roles included | ||
| Integrations included (name each) | ||
| Data migration included? | ||
| Fixed price or day rate? | ||
| What happens if scope changes? | ||
| Support included, and for how long? | ||
| Who owns the code and repository? |
If one quote is silent on several of these rows, that's not a discount - it's cost moved to a change request later. Our who owns the code post covers the last row in more depth, since it's the one most often skipped.
Why the honest answer beats a fake number
Some agencies quote a headline number over the phone to win the meeting, then move the real cost into change requests once you're committed. We'd rather spend thirty minutes understanding your process and give you a proper estimate against a written scope. It takes longer to get to a number, and the number holds up.
If you want to see how the maths changes when you compare custom software against a per-seat product over several years, the five-year cost of per-seat SaaS vs owning your software walks through the formula properly.
The gov.uk guidance on procuring digital services is aimed at the public sector but the scoping discipline behind it - write the requirement before you ask for a price - applies just as well here.
✦ Where this fits
More on this from us: how our pricing works.