Who it's for: anyone starting a new role in a SaaS or tech finance team, from finance assistant to financial controller, especially if it's your first SaaS job.
What you'll get: a 30-60-90 day plan with checklists, the SaaS-specific things to learn first, a worked example of the journals you'll see in week one, AI tips, and a ready-made message for your first one-to-one.
Reading time: about 10 minutes. Ideally before day one, but day three also works.
Why the first 90 days matter
The first three months set how people see you, and how quickly you become useful. In SaaS finance, much of what you need to know lives in the billing system, the deferred revenue schedule and people's heads, not the ledger. A clear plan helps you learn fast, avoid "fixing" things you don't yet understand, and show progress your manager can see.
Key terms you'll hear in week one
- ARR and MRR: annual and monthly recurring revenue. Subscription run-rate measures, not the same as revenue in the accounts.
- Deferred revenue: money billed for service not yet delivered, held on the balance sheet and released to revenue over time.
- Billing system: the tool that raises subscription invoices, such as Stripe Billing or Chargebee. It usually feeds the ledger.
- Churn: customers or revenue lost when subscriptions are cancelled or reduced.
- Close: the month-end process of finishing the accounts.
- Board pack: the monthly or quarterly report to the board, usually with SaaS metrics alongside the accounts.
Days 1 to 30: listen, map and learn
| Task | What "done" looks like | |
|---|---|---|
| ☐ | Agree expectations with your manager | You know what success looks like at 30, 60 and 90 days, written down |
| ☐ | Get system access: ledger, billing, payroll reports, expenses, shared drives | Access confirmed and tested; anything missing chased |
| ☐ | Read the last three months' management accounts and board packs | You can explain the main revenue and cost lines and the key metrics |
| ☐ | Read the close checklist and calendar | You know which tasks are yours and when they're due |
| ☐ | Shadow one full month-end close | Notes on each step, who does it, and where the data comes from |
| ☐ | Learn the chart of accounts and the main balance sheet accounts | You know what lives in deferred revenue, accruals, prepayments and the control accounts |
| ☐ | Meet key people outside finance: sales ops, RevOps, HR, engineering lead, the CEO's assistant | A short list of who to ask for what |
| ☐ | Read the last audit findings (management letter), if there is one | You know the known weak spots |
AI shortcut: if your company has an approved AI tool, give it the close checklist and your shadowing notes and ask it to build a one-page process map: steps, owners, inputs and outputs, with gaps marked "unknown". Take the map to your manager and fill the gaps together. It's a fast way to show you've understood, and to find what nobody wrote down.
Days 31 to 60: own your area
| Task | What "done" looks like | |
|---|---|---|
| ☐ | Run your close tasks with a reviewer | Tasks done on time with fewer review points each month |
| ☐ | Reconcile your balance sheet accounts | Each one has a reconciliation, evidence and sign-off |
| ☐ | Trace one customer from contract to cash | You've followed a deal from CRM to billing, invoice, deferred revenue, revenue and cash |
| ☐ | Learn how ARR is calculated here | You can explain why ARR, MRR and revenue differ this month |
| ☐ | Keep a list of questions and ideas, but don't act on the ideas yet | A running document, with "why we do it this way" answers added |
| ☐ | Write or update desk notes for your tasks | Someone else could do your tasks from your notes |
Days 61 to 90: improve one thing
| Task | What "done" looks like | |
|---|---|---|
| ☐ | Pick one improvement with your manager | Small, clearly useful, and inside your area (for example, a reconciliation template or an automated report) |
| ☐ | Deliver it and measure it | Time saved or errors avoided, in numbers |
| ☐ | Hold a 90-day review with your manager | What's gone well, what's next, and development goals agreed |
| ☐ | Share what you've learned | Updated desk notes and process map saved where the team can find them |
AI shortcut: when choosing your improvement, ask an approved AI tool to read your question list and desk notes and group the pain points by theme and likely time cost. It gives you a shortlist to discuss. You and your manager pick; AI just sorts the pile.
Worked example: the journals you'll see in week one
MonthEndClub Co Ltd, a fictional UK SaaS company, signs a customer on 1 October for a 12-month subscription at £12,000 plus VAT, billed annually upfront. VAT is 20% in this example.
1 October: invoice raised. Nothing has been delivered yet, so the £12,000 goes to deferred revenue.
| Account | Dr | Cr |
|---|---|---|
| Trade debtors | £14,400 | |
| Deferred revenue | £12,000 | |
| VAT output tax | £2,400 |
31 October: one month delivered. £12,000 ÷ 12 = £1,000 moves to revenue.
| Account | Dr | Cr |
|---|---|---|
| Deferred revenue | £1,000 | |
| Revenue | £1,000 |
Where you are at 31 October: revenue £1,000; deferred revenue £11,000; and if the customer hasn't paid, debtors £14,400. Meanwhile ARR for this customer is £12,000 and MRR is £1,000. Seeing those four numbers side by side, and knowing why they differ, is one of the fastest ways to get up to speed in SaaS. Under IFRS 15 and FRS 102, revenue follows delivery of the service over time. If you report under US GAAP (ASC 606), the answer for a simple subscription like this is the same.
Common mistakes in the first 90 days
- Changing processes in month one. There's often a reason, even if it's a bad one. Learn it first.
- Not asking the "obvious" question. New starters get a grace period for basic questions. Use it.
- Only learning the ledger. In SaaS, the billing system and CRM drive most of the numbers.
- Keeping notes only in your head. Write them down from day one; they become your desk notes.
- Taking over someone's spreadsheet without review. Check the formulas and the reconciliation before you rely on it.
- Using AI tools before checking the policy. Find out which AI tools are approved before putting any company data into one.
Tools that can help
You'll probably meet a ledger (Xero, QuickBooks, Sage or NetSuite), a billing system (Stripe or Chargebee), a spend tool (such as Pleo), reporting tools (such as Fathom) and a lot of Excel or Google Sheets. Learn the reports each one produces and how they feed the close. Knowing the tools helps, but understanding the process is what makes you useful.
Ready-made message: before your first one-to-one
Copy, adjust and send a day or two before your first proper catch-up.
Subject: Ahead of our catch-up on [day]
Hi [name],
Thanks for a great first week. Ahead of our catch-up, I've put together a few things to agree so I can focus on what matters most:
- What would a great first 30, 60 and 90 days look like from your side?
- Which close tasks and reconciliations will I own, and by when?
- Who are the three people outside finance I should meet first?
- Is there a known problem area you'd like me to look at once I'm up to speed?
- Which AI tools are approved for finance data here?
I'll bring my notes from shadowing so far. Happy to adjust if you'd like to cover something else.
Thanks, [your name]
Key takeaways
- Agree what success looks like at 30, 60 and 90 days, in writing.
- Shadow a full close before changing anything.
- Trace one customer from contract to cash; it teaches you more than any manual.
- Write desk notes as you go and deliver one measured improvement by day 90.
- Check which AI tools are approved, then use them to map processes and sort ideas, with your judgement on top.
FAQs
I've never worked in SaaS. What should I learn first?
Deferred revenue and how it's released, then the difference between ARR, MRR and revenue. After that, how the billing system feeds the ledger. Most SaaS-specific close tasks hang off those three.
How soon should I suggest improvements?
Many people keep a list from week one but wait until they've seen at least one full close, often two, before proposing changes. The 61 to 90 day window is a natural point to deliver one.
Can I use AI to get up to speed faster?
Yes, within company policy. Approved AI tools are useful for explaining unfamiliar terms, turning shadowing notes into process maps, and explaining inherited spreadsheet formulas. Check its explanations with colleagues, and only put company data into approved tools.
What if there's no close checklist?
That's your first useful piece of work. Build it from your shadowing notes, check it with the team, and you'll have helped everyone, not just yourself.
Related guides
- SaaS Finance Glossary: 60 Terms in Plain English
- The SaaS Month-End Close Checklist
- ARR vs MRR vs Revenue: Why They Don't Match and How to Reconcile Them
- Moving into SaaS After Qualifying
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This guide is general information about common practice. It isn't tailored to any business, and standards, tax rules and figures change. Check your own circumstances, the latest rules and, where needed, a qualified professional before acting.
Last reviewed: October 2026.