The verdict in three sentences
A custom client portal for a 30-person practice should be budgeted at 25,000 to 60,000 GBP, delivered in 10 to 14 weeks, while an off-the-shelf document collection tool charges 8 to 25 GBP per client per month. Beyond 300 active clients, or as soon as you need a deep Xero integration and Making Tax Digital workflows, custom becomes profitable within 2 to 3 years. In every case, require e-signature, automated chasers and UK or EU hosting.
The real cost of chasing records
In a 30-person London practice with 450 clients (sole traders, landlords, small limited companies), staff spend on average 6 hours a week chasing bank statements, purchase invoices, expense receipts and VAT evidence by email and phone. Over 46 weeks that is 276 hours, or more than 15,000 GBP of loaded time at 55 GBP an hour, before counting late filings and documents lost in inboxes.
Making Tax Digital for Income Tax, which applies from April 2026 to sole traders and landlords above 50,000 GBP of qualifying income, adds quarterly updates. The chasing workload grows from once a year to four times a year for those clients.
A client portal solves this with four functions: a list of expected documents per client and period, drag-and-drop or mobile photo upload, automated reminders at day 3 and day 7, and a staff dashboard that shows incomplete files at a glance. Add e-signature for engagement letters and returns, and a document vault where clients find their accounts and filings.
Custom or SaaS: the costed comparison
| Criterion (2026) | Market SaaS tool | Custom portal |
|---|---|---|
| Entry cost | 0 to 2,500 GBP setup | 25,000 to 60,000 GBP |
| Recurring cost | 8 to 25 GBP per client per month | Hosting and maintenance 400 to 900 GBP/month |
| Annual cost for 450 clients | 43,200 to 135,000 GBP at list price, often negotiated | 4,800 to 10,800 GBP |
| Xero integration | Standard connectors, sometimes partial | Custom integration with the Xero API |
| Practice branding | Logo and colours | Fully branded experience |
| Ownership of data and code | Data exportable, code not | Code and data owned by the practice |
| Time to go live | 2 to 6 weeks | 10 to 14 weeks |
List SaaS prices are usually tiered: at 450 clients, practices often negotiate around 4 to 8 GBP per client per month, or 21,600 to 43,200 GBP a year. Custom keeps the edge over three years once that volume is exceeded or when market connectors do not cover your workflow. These figures are 2026 orders of magnitude.
Detailed budget for a custom portal
| Module | Indicative budget | Detail |
|---|---|---|
| Discovery and wireframes | 3,000 to 5,500 GBP | Workshops with 3 to 5 staff |
| Client area and document upload | 7,500 to 15,000 GBP | Web and mobile, photo, basic OCR |
| Document lists and automated chasers | 3,500 to 7,500 GBP | Templates per client type, MTD quarters |
| Staff dashboard | 3,500 to 8,500 GBP | Filters by deadline and manager |
| E-signature | 2,000 to 4,500 GBP | eIDAS or UK qualified provider, per-signature fees extra |
| Xero integration | 4,000 to 11,000 GBP | Contacts, documents, practice manager data |
| Security, UK hosting, UK GDPR | 1,500 to 4,000 GBP | Encryption, two-factor login, audit logs |
E-signature adds a unit cost of 0.40 to 1.60 GBP per envelope depending on the provider. For hosting, choose a UK or EU provider certified ISO 27001 and keep Cyber Essentials Plus in view, as some clients now ask for it.
Mini case study
Sophie, partner in a 30-person accounting practice in London, manages 450 clients. She receives a SaaS offer negotiated at 6 GBP per client per month, or 32,400 GBP a year and 97,200 GBP over three years. The custom portal is priced at 42,000 GBP, plus 600 GBP a month for maintenance and hosting, or 63,600 GBP over three years.
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In both cases she targets a drop in chasing from 6 to 2 hours a week, or 184 hours and about 10,100 GBP of loaded time recovered each year. The 33,600 GBP three-year gap in favour of custom pays for the direct Xero integration and MTD quarterly workflows. This case is an illustrative example.
FAQ
How much does a client portal for an accounting firm cost in 2026?
A custom portal costs 25,000 to 60,000 GBP depending on modules, plus 400 to 900 GBP a month of maintenance. A SaaS tool costs 8 to 25 GBP per client per month at list price.
How long does it take to roll out?
Allow 10 to 14 weeks of development, then 4 to 6 weeks of gradual rollout to clients. Start with 30 to 50 pilot clients before going firm-wide.
Will older or less digital clients use it?
Photo upload from a smartphone and SMS reminders make the difference. Practices typically see 60 to 80 % adoption after 6 months when staff guide the first upload.
Does it help with Making Tax Digital?
Yes, quarterly document lists and reminders align with MTD for Income Tax deadlines from April 2026. The Xero integration then feeds the bookkeeping without re-keying.
Where should accounting records be hosted?
In the UK or the EU, with an ISO 27001 certified host, encryption and two-factor login. Plan retention in line with UK record-keeping rules of 5 to 6 years depending on the client type.
Let's scope your project. Tell us your client count and practice software: we price a client portal with document upload, chasers, e-signature and Xero integration, with an indicative budget and a 10 to 14 week plan. Detailed quote within 48 h. WhatsApp +221 77 596 93 33.
Mohamed Bah
Fondateur, Kolonell
Passionate about digital and entrepreneurship in Africa, Mohamed has been helping Sénégalese businesses with their digital transformation since 2020. Founder of Kolonell, he believes every SME deserves a professional and accessible online présence.
