Looking for a Karbon alternative?
Karbon is one of the best practice management products ever made — and on its UK price list it is £34–£49 per user per month, so the bill grows with every person you add. If you love the idea of Karbon but not the per-user maths, here's how Sodium compares.
The per-user pricing problem
Karbon prices per user: on the UK price list the Team plan is £34/user/month on annual billing (£44 monthly), and Business is £49/£59. For a five-person firm that's £170–£245 every month before add-ons — and every hire, part-timer, or seasonal helper adds another seat.
Sodium prices by client count instead, with up to 25 users included. A firm with 250 clients pays £89/month on the Standard package — less than two Business seats on Karbon. Your admin staff, part-timers, and new starters cost nothing extra.
(Both figures from the vendors' public UK price lists, checked 26 August 2026 — see the table below.)
Built for UK practice, not adapted to it
Karbon is a global product with a UK price list. Sodium is a UK product: Companies House lives inside the core client record — confirmation statement and accounts dates flow into your workflows automatically — and proposals, engagement letters and the client portal are built around how UK firms onboard and serve clients. It's founder-owned (Duane Jackson — previously KashFlow and Staffology) with no external investment.
Where Sodium’s time and billing differs
This is the closest fight on this page. Karbon’s time tracking is on every plan — budgets, budget-versus-actual, timesheet approvals, period locking — and Karbon Billing & Payments covers time & materials, fixed-fee, recurring and progress billing with write-ons and write-offs, plus realization by client, team member and service line. If you want an honest answer: on time and WIP the two are broadly matched, and Karbon’s realization reporting is more mature.
Sodium records time against clients, tasks, workflow steps and services, with timers that can start and stop with a workflow step, and puts your whole unbilled position on one screen. Bill a fixed fee against the time logged and the shortfall is written off there and then with a reason attached, entry by entry — or left in WIP to bill later. Write-off analysis by reason, recovery rates and open WIP all come off those same entries. Read more about time tracking, WIP and write-offs.
Two things are genuinely different. Sodium carries a cost rate per person alongside their charge rate, so approved hours become contractor pay runs and you can see what a job cost next to what it recovered — not just what it realized. And all of it is in the price of every package, priced by client count, so the firm that adds a part-timer to get the timesheets in doesn’t pay more for the privilege.
What Karbon does well
Karbon earns its reputation. Its collaborative triage and @mention-driven teamwork are the best in the category, the design is superb, Kai (its AI coworker) is genuinely useful, and for larger multi-office teams the per-user cost can be worth every penny. If you're 20+ collaboration-heavy users, Karbon may well be the right tool — this page is for the smaller UK firms doing the per-seat arithmetic.
Side by side
| Karbon | Sodium | |
|---|---|---|
| Pricing model | Per user — Team £34/user/month (annual billing) or £44 (monthly); Business £49/£59; Enterprise custom | Tiered by client count — up to 25 users included, no per-user charges |
| Example: 5-person firm, 250 clients | £170/month on Team (annual billing, 5 × £34) | £89/month on Standard (price set by client count, not team size) |
| Free tier | — | Free for up to 5 clients |
| Companies House | Integration available | Companies House built into the core client record |
| Client portal | Included | Client portal included |
| AI | Kai, Karbon's in-app AI coworker, plus AI agents | Built-in MCP server — connect Claude and other AI assistants to your practice data |
| Time tracking and WIP | Time tracking and budgets on every plan, with budget-versus-actual, timesheet approvals and period locking | Six ways to log time — against clients, tasks, workflow steps and services — including timers that start and stop with a workflow step, calendar and timesheet views, and your whole unbilled position on one screen |
| Fee billing and write-offs | Time & materials, fixed fee, recurring and progress billing, with write-ons and write-offs, in Karbon Billing & Payments | Bill a fixed fee against logged time and write off the shortfall with a reason, or leave it in WIP to bill later — with write-off, recovery and open-WIP reporting |
| Staff cost and profitability | Realization by client, team member and service line, plus budget versus actual, WIP and AR ageing | A cost rate per person alongside their charge rate, contractor pay runs for approved hours, and cost against profit and recovery on the same entries |
Last checked 26 August 2026. Karbon pricing and features may have changed since — always confirm current details with the vendor. Karbon prices from karbonhq.com/en-GB/pricing, GBP price list. The example row is arithmetic on published per-user prices and assumes no discounts. Time and WIP rows describe what each vendor publishes on its own website as at 10 September 2026. A dash means the capability is not stated in the vendor's published material, not that it is unavailable — check with the vendor. A dash (—) means the item wasn't listed on the vendor's public site when we last checked.
Moving your data
Sodium imports clients, contacts, and service assignments from CSV files with the built-in import tools. Export your client list from Karbon, map the columns, and the data move is typically an afternoon. Your workflows will need setting up fresh in Sodium's workflow builder — budget a day to rebuild your core processes.
Common questions
How much cheaper is Sodium than Karbon for a small firm?
It depends on your team size and client count, because the pricing models differ. Karbon's UK price list charges per user (Team £34/user/month on annual billing; Business £49/£59). Sodium charges by client count with up to 25 users included — a firm with 250 clients pays £89/month total on Standard. A five-person firm with 250 clients would pay £170/month on Karbon Team (annual) versus £89/month on Sodium Standard. Prices checked 26 August 2026.
Does Sodium have Karbon-style workflows?
Sodium has multi-step workflows with conditional steps, automated client emails, recurring task generation, kanban boards, and task teams. It doesn't replicate Karbon's shared-inbox triage model — Sodium's connected mailbox links email to clients and tasks in its own way.
Can I import my clients from Karbon?
Yes — export your client list from Karbon as a CSV and use Sodium's import tools for clients, contacts, and service assignments. Workflows are rebuilt in Sodium's workflow builder rather than imported.
Does Sodium have AI features like Karbon's Kai?
Sodium takes a different approach: instead of an in-app AI assistant, it has a built-in MCP server so AI assistants you already use — like Claude — can securely read and act on your practice data with your permission.
Is there a free trial of Sodium?
Yes — one month free with no card details required, plus a free tier for up to 5 clients with no time limit.
“I've tried other practice management solutions but find they're always heavy work to get them set up - but yours feels a breeze!” — Anne Sievewright, charlesblack.co.uk
Ready to make the switch?
Sodium is free for up to 5 clients, with no card required. Turn off the features you don't need and it fits a practice with 5 clients or 5,000 — import your clients, contacts and services in minutes.