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Accounting · head to head

IRIS KashFlow vs Karbon

IRIS KashFlow logo

IRIS KashFlow

Accounting

Online accounting software for UK sole traders and small businesses

From
£13.5/month
Rated
-
Full reviewWebsite
Karbon logo

Karbon

Accounting

Practice management for accounting firms

From
$59/month
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: IRIS KashFlow advertised monthly prices of £1.35 (Starter) and £2.75 (Business) are a 90% promotional discount off the standard £13.50 and £27.50 rates, and the promotion is described as lasting 6 months before reverting; Karbon monthly billing option only available for teams of 4 or more users
  • Prices and features above were last checked on 29 August 2026.

Where they differ

Only the attributes on which IRIS KashFlow and Karbon actually diverge.

Attributes where IRIS KashFlow and Karbon differ
AttributeIRIS KashFlowKarbon
Starting price£13.5/month$59/month

Identical on both: pricing model (subscription), free tier (No), platforms (Web), user rating (Not yet rated), category (Accounting).

What people use each for

The jobs each tool is most often brought in to do.

IRIS KashFlow

  • business accountingnot Karbon
  • invoicing and billingnot Karbon
  • VAT managementnot Karbon

Karbon

  • Automating client document collection for tax practice intakenot IRIS KashFlow
  • Tracking all client requests in workflows tied to jobsnot IRIS KashFlow
  • Aligning hours worked with billable time per engagementnot IRIS KashFlow
  • Automating period close by connecting practice management to accountingnot IRIS KashFlow
  • Streamlining client document submission and approval workflowsnot IRIS KashFlow

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

IRIS KashFlow

  • Advertised monthly prices of £1.35 (Starter) and £2.75 (Business) are a 90% promotional discount off the standard £13.50 and £27.50 rates, and the promotion is described as lasting 6 months before reverting
  • Listed prices are in GBP plus VAT, and the platform's plans are built around UK VAT filing rather than other tax regimes
  • Annual pricing is quoted at RRP £162/year (Starter) and £291.50/year (Business) before the same promotional reduction

Karbon

  • Monthly billing option only available for teams of 4 or more users
  • Team plan at $59/month per user minimum cost may be expensive for smaller practices
  • No seat license discounts published; scaling costs linearly with user count

Pricing, plan by plan

IRIS KashFlow

£13.5/month
  • Starter Monthly$13.5/month
    • 10 invoices
    • up to 25 bank transactions
    • single user access
  • Business Monthly$27.5/month
    • unlimited invoices
    • unlimited bank transactions
    • multi-user access
  • Starter Annual$162/year
    • 10 invoices
    • up to 25 bank transactions
    • single user access
  • Business Annual$291.5/year
    • unlimited invoices
    • unlimited bank transactions
    • multi-user access

Karbon

$59/month
  • Team$59/month
    • Per-user pricing
    • Designed for small accounting firms
    • Minimum team size of 4 for monthly billing
  • Business$89/month
    • Per-user pricing
    • Workflow automation
    • Integrations for growing practices
  • Enterprise$null/mo
    • Custom pricing
    • Tailored for large accounting firms
    • Dedicated support

Which should you pick?

Choose IRIS KashFlow if

Nothing in the data separates IRIS KashFlow from Karbon on the points above - pick on price and on how each one feels to use.

IRIS KashFlow review

Choose Karbon if

Nothing in the data separates Karbon from IRIS KashFlow on the points above - pick on price and on how each one feels to use.

Karbon review

Questions people ask

Is IRIS KashFlow or Karbon better?
Neither clearly leads. IRIS KashFlow starts at £13.5/month and Karbon at $59/month, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, IRIS KashFlow or Karbon?
IRIS KashFlow starts at £13.5/month and Karbon at $59/month.
Does IRIS KashFlow or Karbon run on more platforms?
Both run on Web, so platform support will not decide this one for you.
What is IRIS KashFlow best used for?
IRIS KashFlow is most often used for business accounting, invoicing and billing, vat management. Of those, business accounting and invoicing and billing are not what Karbon is typically brought in for.

Answered from the vendors’ own pages

IRIS KashFlow: What are IRIS KashFlow's core features across all plans?

All IRIS KashFlow plans include unlimited quotes, online VAT submission, mobile app access, 50+ reports, bank feeds, receipt capture, multi-currency support, and payroll for up to 5 employees.

Source
Karbon: How much does Karbon cost?

Karbon pricing starts at $59 per user per month (Team plan, billed annually) or $79 per user per month (monthly billing for 4+ users). Business plan is $89/month annual or $99/month monthly. Enterprise pricing is custom.

Source
IRIS KashFlow: Are there promotional discounts for new IRIS KashFlow customers?

Yes, new customers receive a 90% discount for 6 months on both Starter and Business monthly plans.

Source
Karbon: Is there a discount for annual billing on Karbon?

Yes, Karbon offers annual billing at a discount compared to monthly. Team plan is $59/month annually versus $79/month monthly. Business plan is $89/month annually versus $99/month monthly.

Source
IRIS KashFlow: Can multiple users access IRIS KashFlow on the Starter plan?

No, the Starter plan is limited to single-user access only. Multi-user access requires the Business plan.

Source
Karbon: What is the minimum user requirement for monthly billing on Karbon?

Karbon requires a minimum team size of 4 users to access monthly billing. Teams smaller than 4 must choose annual billing.

Source
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