# How much does it cost to build an internal tool that replaces a spreadsheet?

URL: https://yarigai.ai/guides/internal-tool-cost
Author: Deniz Sancar, founder of Yarigai (https://denizsancar.com)
Publisher: Yarigai, a done-for-you AI agency in London, UK (https://yarigai.ai)
Published: 7 November 2026. Updated: 7 November 2026.

## Short answer
A custom internal tool that replaces a spreadsheet costs **£10,000 to £30,000** to build in the UK in 2026, according to published agency price lists, and takes 4 to 10 weeks. Hosting a low-traffic tool costs about £50 a month, and agencies budget 15% to 25% of the build each year for maintenance. Off-the-shelf builders cost less up front. monday Standard is £11 a seat a month, and Retool charges £12 per internal user on its Business plan.

## At a glance
| Question | Answer |
|---|---|
| Simple internal tool | £10,000 to £25,000, 4 to 8 weeks (TotalSoft, May 2026) |
| Workflow app that replaces spreadsheets | £15,000 to £30,000, 6 to 10 weeks (Softomate, October 2026) |
| Large replacement of 14 shared files, 25 users | £45,000 to £110,000, 3 to 4 months (Kolonell, October 2026) |
| Hosting | About £50 a month for a low-traffic internal tool |
| Maintenance | 15% to 25% of the build cost a year (agency rule of thumb) |
| No-code alternatives | Notion Business £16.50, monday Standard £11, Airtable Business $45 per seat a month (November 2026) |
| Retool Business | £40 per builder and £12 per internal user a month, annual billing |
| Hours saved to pay back a £15,000 build in two years | About 11.4 hours a week at median full-time pay |

No independent survey covers internal tool build costs. These ranges come from agencies that sell the work.

## What drives the price of an internal tool
The price depends on how many people use the tool, how many systems it connects to and how much data has to move across. A single-team tracker sits at the bottom of the range. A tool that replaces a dozen linked workbooks costs several times more.

| Type of build | Build cost | Timeline | Source |
|---|---|---|---|
| Simple internal tool, described as replacing complex spreadsheets | £10,000 to £25,000 | 4 to 8 weeks | TotalSoft, May 2026 |
| Workflow app replacing spreadsheets or manual processes | £15,000 to £30,000 | 6 to 10 weeks | Softomate, October 2026 |
| Replacement of 14 shared Excel files for 25 users | £45,000 to £110,000 | 3 to 4 months | Kolonell, October 2026 |

Kolonell's London breakdown shows where the money goes on a large job. The core of accounts, permissions, change history and a dashboard costs £15,000 to £26,000. Data migration adds £3,000 to £7,500 and integrations £3,500 to £22,000. Its timeline includes a month of running the new tool in parallel with Excel before the switch.

The main cost drivers:
- Users and roles. A tool where staff see only their own rows needs permissions that a shared sheet never had.
- Integrations with Xero, Shopify, a CRM or email, each with its own API.
- Data migration, which means cleaning years of inconsistent rows before import.
- Approvals and an audit trail, so you know who changed a figure and when.

## Off-the-shelf alternatives: Retool, Airtable, Notion and monday
No-code and low-code tools cost a few hundred to a few thousand pounds a year for a small team, which is far less than a custom build. Someone still has to build the app inside them, and the bill grows with every seat.

| Tool | List price per seat a month (checked 7 November 2026) | Notes |
|---|---|---|
| Retool (UK) | Team £8 per builder, £4 per internal user; Business £40 per builder, £12 per internal user, annual billing | Monthly billing £10 and £6 on Team, £52 and £14 on Business; free for up to 5 users |
| Airtable | Team $20, Business $45, annual billing, USD | Free plan; Enterprise Scale is custom |
| Notion (UK) | Plus £8.50, Business £16.50, yearly billing | Free plan; £10 and £19.50 billed monthly |
| monday work management (UK) | Basic £8, Standard £11, Pro £17, annual billing | Free for 2 seats; paid plans start at 3 seats |

For a 10-person team, the yearly list cost works out as follows:
- monday Standard: 10 × £11 × 12 = £1,320.
- Notion Business: 10 × £16.50 × 12 = £1,980.
- Retool Business with 2 builders and 8 internal users: (2 × £40 + 8 × £12) × 12 = £2,112.
- Airtable Business: 10 × $45 × 12 = $5,400.

These tools win when the process fits their building blocks and one person on the team enjoys setting them up. A custom build wins when the workflow needs logic, integrations or permissions the tool can't model, or when seat counts climb. For the wider comparison, see [is it cheaper to build your own tools than pay for SaaS](/guides/build-vs-buy-saas) and [Zapier, Make, n8n or custom code](/guides/zapier-vs-make-vs-n8n-vs-custom-code).

## When a spreadsheet is still the right answer
Keep the spreadsheet if it costs less than about 3 hours of staff time a week to maintain. Below that, the running costs of a typical £15,000 build outweigh the saving, as the payback section shows.

A spreadsheet is still the right tool when:
- One or two people edit it, and nobody needs a restricted view.
- It holds a model or reference data, not a live workflow with handoffs.
- The process changes every week, so a build would chase a moving target.
- Mistakes are cheap and easy to spot.

## Signs you have outgrown the spreadsheet
You have outgrown the sheet when several people depend on it and an error in it costs real money. Research on spreadsheet accuracy is old but consistent. Raymond Panko's 2000 paper for the European Spreadsheet Risks Interest Group says 15 years of research agree that spreadsheet errors are "both common and non-trivial". It adds that only one checking method, cell-by-cell inspection, had been shown to work.

File limits catch people out too. In October 2020 Public Health England left 15,841 positive Covid cases out of its daily figures. The Register, citing the BBC, put it down to the 65,536-row limit of the old .XLS format, which capped each file at about 1,400 cases.

Common signs it's time to move:
1. Several people edit the same file and you keep dated copies to be safe.
2. Someone types the same data twice, from email or another system into the sheet.
3. Staff or clients need to see only their own rows.
4. You need approvals and a record of who changed what.
5. One person understands the formulas, and work stops when they're on holiday.
6. The weekly report takes hours of copying and pasting.

## A payback example with the arithmetic shown
A £15,000 internal tool pays back in about 22 months if it saves 12 hours of staff time a week. The inputs below are an example, so swap in your own hours.

- Five people spend a combined 15 hours a week on a shared operations sheet. The tool removes 12 of those hours.
- Staff cost is £19.67 an hour, the ONS median for full-time employees in April 2025, excluding overtime. Employer National Insurance and pension come on top, so the real cost is higher.
- The year has 46 working weeks, allowing for holidays.

| Line | Arithmetic | Per year |
|---|---|---|
| Time saved | 12 hours × 46 weeks × £19.67 | £10,858 |
| Hosting | £50 a month × 12 | £600 |
| Maintenance at 15% of build | £15,000 × 0.15 | £2,250 |
| Net saving | £10,858 − £600 − £2,250 | £8,008 |
| Payback on a £15,000 build | £15,000 ÷ £8,008 | 1.9 years (about 22 months) |

At 25% maintenance (£3,750 a year), the net saving falls to £6,508 and payback stretches to about 28 months.

The same numbers give a rule of thumb. Each hour saved per week is worth £904.82 a year (46 × £19.67).
- Covering running costs of £2,850 a year needs about 3.2 hours a week.
- Paying back £15,000 inside two years needs about 11.4 hours a week, since (£7,500 + £2,850) ÷ £904.82 = 11.4.
- Paying back inside one year needs about 19.7 hours a week, since (£15,000 + £2,850) ÷ £904.82 = 19.7.

Kolonell publishes a larger vendor case study. A £68,000 project with £1,300 a month of maintenance cost £83,600 in year one and paid back in 15 to 16 months against estimated gains of £64,500 a year. That is the vendor's own case and has not been independently checked.

## Running costs and who owns the code
Plan for hosting, maintenance and changes every year, and get ownership of the code in writing before the build starts.

### Running costs
- Hosting costs £50 to £500 a month, with about £50 for a low-traffic internal tool, according to Softomate. Kolonell quotes £50 to £250 a month for its 25-user example.
- Maintenance runs at 15% to 25% of the build cost a year in Softomate's figures. On a £15,000 to £30,000 build that is £2,250 to £7,500 a year. This is an agency rule of thumb, and no independent study backs it.
- Softomate lists new features and iteration at £5,000 to £30,000 a year, and emergency out-of-hours fixes at £80 to £150 an hour.

### Ownership
UK copyright law decides who owns the code, and the default may surprise you. Under section 11 of the Copyright, Designs and Patents Act 1988, the author of a work is the first owner of its copyright, and an employer owns work its employees create in the course of their job unless agreed otherwise. A freelancer or agency is not your employee, so it owns the code it writes unless the contract transfers it. Section 90(3) says an assignment of copyright is not effective unless it is in writing and signed by the assignor. This is a summary, not legal advice.

Before you sign, ask who owns the code, the hosting account, the database and the domain, and whether you can move all four without the developer.

## How Yarigai builds internal tools
Yarigai builds internal tools that replace spreadsheets as part of its [AI operations](/services/ai-operations) work, along with document reading and filing. It builds inside the client's own accounts, so the client owns the code, the data and the accounts from day one. That settles the ownership question above before the build starts.

- Free 30-minute scope call on Google Meet. The client keeps the notes whether they hire Yarigai or not.
- Blueprint of about a week, credited to the build, with a written plan, a clickable prototype, the monthly running cost, a fixed price and the payback maths.
- Build of 2 to 6 weeks in the client's accounts, with a demo of working software every week. A single workflow can go live in about two weeks.
- Optional monthly care, which the client can cancel any month and keep everything.
- AI and hosting bills are paid by the client at cost.

The guarantee is "If the build isn't profitable for you, we won't build it." If the blueprint's maths doesn't come out ahead within the first year, Yarigai doesn't take the job. In the rule of thumb above, that bar is the year-one payback line, not the two-year one.

Yarigai's founder, Deniz Sancar, replaced 10 software subscriptions with tools Yarigai built for its own team, saving about £3,600 a year (£301 a month).

## Common questions
### How long does it take to build an internal tool that replaces a spreadsheet?
UK agencies quote 4 to 8 weeks for a simple internal tool and 6 to 10 weeks for a workflow app, and Kolonell gives 3 to 4 months for a 25-user replacement of 14 linked files. Yarigai builds in 2 to 6 weeks, and a single workflow can go live in about two weeks.

### Is Airtable or Retool cheaper than a custom build?
Usually, for a small team with a simple process. Ten Airtable Business seats cost $5,400 a year, and Retool Business for 2 builders and 8 users costs £2,112 a year, both at November 2026 list prices. A custom build costs more up front but has no per-seat fee, so it gains ground as headcount grows.

### Can an internal tool pull data from Xero, Shopify or my CRM?
Yes, through each system's API. Each connection adds cost. Kolonell's London breakdown puts integrations at £3,500 to £22,000 on a large project, and simpler tools with one or two connections sit at the low end.

### Can we keep using Excel while the new tool beds in?
Yes, and you should. Kolonell's timeline includes a month of running the new tool alongside Excel before the switch. A custom tool can also export to CSV, so finance can keep its own models in Excel.

### Who owns the code if an agency builds my internal tool?
Under the Copyright, Designs and Patents Act 1988, the agency owns the code it writes unless a signed written assignment transfers it to you. Check the contract covers the code, the hosting account, the database and the domain. At Yarigai the client owns the code, data and accounts from day one.

### What does an internal tool cost to run each year?
Plan for hosting of about £50 a month for a low-traffic tool and maintenance of 15% to 25% of the build cost a year. On a £15,000 build that is £2,850 to £4,350 a year in total. Changes and new features cost extra.

## Sources
1. [How Much Does Custom Software Cost in the UK? (2026 Guide)](https://totalsoft-it-solutions-website.pages.dev/blog/how-much-does-custom-software-cost-uk-2026), TotalSoft IT Solutions, published 18 May 2026.
2. [The True Cost of a Custom Web Application for UK Businesses](https://www.softomatesolutions.com/blog/web-application-cost-uk/), Softomate Solutions, updated 1 October 2026.
3. [Replacing spreadsheets with a web app for an SME in London: cost (2026)](https://kolonell.com/en/blog/replace-spreadsheets-with-web-app-sme-london-cost-2026), Kolonell, published 8 October 2026.
4. [Retool Pricing: Find the plan that works for you](https://retool.com/pricing), Retool, checked 7 November 2026.
5. [Airtable Pricing | Compare Plans, Features & Costs](https://www.airtable.com/pricing), Airtable, checked 7 November 2026.
6. [Notion Pricing Plans: Free, Plus, Business, & Enterprise](https://www.notion.com/pricing), Notion, checked 7 November 2026.
7. [monday.com pricing and plans](https://monday.com/pricing), monday.com, checked 7 November 2026.
8. [Spreadsheet Errors: What We Know. What We Think We Can Do](https://arxiv.org/abs/0802.3457), Raymond R. Panko, EuSpRIG 2000 proceedings, posted to arXiv 23 February 2008.
9. [What a Hancock-up: Excel spreadsheet blunder blamed after England under-reports 16,000 COVID-19 cases](https://www.theregister.com/2020/10/05/excel_england_coronavirus_contact_error/), The Register, published 5 October 2020.
10. [Employee earnings in the UK: 2025](https://www.ons.gov.uk/employmentandlabourmarket/peopleinwork/earningsandworkinghours/bulletins/annualsurveyofhoursandearnings/2025), Office for National Statistics, published 23 October 2025.
11. [Copyright, Designs and Patents Act 1988, section 11](https://www.legislation.gov.uk/ukpga/1988/48/section/11), legislation.gov.uk, checked 7 November 2026.
12. [Copyright, Designs and Patents Act 1988, section 90](https://www.legislation.gov.uk/ukpga/1988/48/section/90), legislation.gov.uk, checked 7 November 2026.