Fractional CFO for SaaS, AI & Tech Founders
in London & the UK
Investor-ready financials, reliable forecasts, and a CFO who answers almost immediately. Fixed retainer. No day rates. No surprises.
Trusted By
Do you recognise this?
Most SaaS founders between £500K and £5M ARR don't have anyone looking at their numbers. If two or more of these apply, your data isn't investor-ready.
What founders say about us
Read all reviews on Trustpilot
"Constantin knows his stuff and it was a really professional experience working with him. We will keep engaging Constantin to support us with our financial strategy. Only positive things to say about his services."
"Our CFO Constantin is always there for us, with clear reporting, useful insights (that we can't see as we are too close), and quick replies to our questions. A fractional CFO makes so much sense. A lifetime of experience at a fraction of the cost."
Everything your finance function needs
From messy books to investor-ready financials - hands-on, not advisory-only.
Sort the past before you sell the future
Investors are now using AI for due diligence. Every inconsistency in your data gets flagged in minutes. These are the problems they find most often:
Revenue that doesn't add up
The recurring revenue you quote in investor meetings doesn't match the revenue in your accounts. Renewal contracts booked in the wrong period, annual subscriptions recognised as a lump sum instead of spread across 12 months.
Inflated gross margin
Your margin says 90% because engineering and customer success costs are classified as operating expenses instead of cost of sales. Investors always scrutinise this and a wrong number destroys trust instantly.
Customer concentration risk
Your top 3 customers make up over 50% of revenue. That's not a valuation multiplier, that's a risk discount. And you need the data to prove it's not as bad as it looks.
No retention or efficiency metrics
No way to show how much revenue you keep from existing customers, how long it takes to recover the cost of acquiring one, or how your customer base behaves over time. If your revenue data is wrong, none of these numbers can be trusted.
Different from every other fractional CFO
Most give you advice. We give you advice - and do the work.
Fixed retainer
One monthly fee covers everything. No day rates, no surprise invoices.
SaaS/AI-specialist
Deep expertise in MRR, ARR bridges, unit economics, and investor language.
Hands-on
We restructure your chart of accounts and fix your gross profit margin - not just tell you to.
Always available
Unlimited email support. 90% replied within 2 hours, guaranteed within 24.
Hey, I'm Constantin
I'm a Chartered Accountant and the founder of ScaleWithCFO. I work with SaaS, AI, and tech founders across London and the UK who need a senior finance partner - without a full-time hire.
Whether you're preparing to raise, cleaning up historical data, or planning an exit - I handle it hands-on so you can focus on building.
From first call to fully operational in 90 days
Every engagement follows the same proven structure. By day 90, your financials are clean, your forecast is built, and your first board pack is delivered.
Sort the past - clean up & restructure your financials
- Rebuild your chart of accounts by department (Sales, Marketing, Dev, G&A)
- Fix how revenue is recorded - spread annual contracts monthly instead of lump sums
- Split costs correctly between cost of sales and operating expenses
- Reconcile Xero with your subscription data (Stripe, HubSpot, CRM)
- Audit gross profit margin and fix COGS allocation
- Review historical data so investors see a clean, accurate trail
Cash flow forecast & financial planning
- Build an operational cash flow forecast with scenario analysis
- Calculate runway under conservative, base, and best-case scenarios
- Review your sales pipeline and model expected revenue
- Set budgets with your team leaders for the next 12 months
- Start building unit economics - acquisition cost, lifetime value, payback period
- Identify cash leaks and opportunities to extend runway
First board pack delivered
- Monthly report with KPIs, management commentary, and recommendations
- Revenue waterfall - new customers, expansions, downgrades, churn, net new
- Retention metrics - how much revenue you keep, customer renewal rates
- Efficiency metrics - how fast you recover acquisition costs, burn vs growth
- Customer concentration and cohort analysis
- Strategic planning aligned to your fundraising or exit timeline
Monthly board pack, management commentary, cash flow updates, unlimited email support, and regular strategic meetings. Financial modelling and data room preparation for fundraising or exit from month 4.
Ready to get your finances under control?
Free 30-minute discovery call. No obligation - just a straight conversation.