What will your software project actually cost?
Every guide online, ours included, will tell you UK custom software runs between £15,000 and £500,000. That range is true and almost useless. This works out the number for the thing you are building: effort in person-days, a blended day rate, a timeline, and what it costs to keep running once it is live.
Seven questions. No email, no sign-up, no waiting for a callback.
Estimate: £46,000 – £155,000 over 17–30 weeks.
17–30 weeks · 104–179 person-days · £450–£850/day blended
- Running it, per year
- £8k – £39k
- First year, all in
- £54k – £194k
- Hosting
- £102–£639/mo
For context, we publish £40k – £150k for a customer-facing web app. Your scope narrows it to the figure above.
No email required. Nothing is sent until you choose to.
What this number is, and isn't
It is a budgeting figure built from the same day rates and effort assumptions we use to quote real work. It is not a quote. The single biggest source of error is scope you have not thought of yet, and it moves the number up, never down.
If the number changes the question
- Not sure this should be built at all — that is a fractional CTO conversation.
- It was already built and went wrong — rescuing costs less than rebuilding.
Questions people ask
How accurate is the software cost calculator?
It produces a budgeting range, not a quote. The effort assumptions and day rates behind it are the ones we use to price real UK projects, so the range is realistic for a scope that is well understood. In practice the largest source of error is scope nobody has thought of yet, which moves the figure up rather than down.
How does it work out the cost?
Bottom-up. Each project type has a base effort in person-days; every feature, integration, compliance requirement and design choice you select adds days or applies a multiplier. The total effort is multiplied by a blended day rate for the delivery model you pick, and the timeline is derived from how many person-days a realistic team delivers per week.
What are UK software developer day rates in 2026?
Senior engineers at UK agencies typically run £450–£850 per day, UK freelancers £350–£700, nearshore teams in Eastern Europe £180–£350, and offshore teams £90–£180. The calculator applies a coordination overhead to the cheaper options, because distance costs days — which is why the day-rate saving never lands in full.
Do I need to give my email to see the result?
No. The estimate appears as you answer, nothing is gated, and nothing is sent anywhere unless you choose to get in touch. You can copy a link to your result and share it with whoever signs off the budget.
What ongoing costs should I budget for after launch?
Budget 15–20% of the original build cost per year for maintenance and updates, plus hosting, which typically runs £50–£500 per month depending on scale. The calculator adds both and shows a first-year total alongside the build figure.
Want the reasoning behind every figure in this calculator — day rates, what drives cost, the hidden line items most quotes leave out?
Read the full UK cost guide