Key points
A controller is accountable for the accuracy of the financial statements and runs the accounting function.
Core areas are the close, revenue recognition, balance sheet reconciliations, internal controls and reporting.
Each area should produce evidence an auditor can test, such as signed reconciliations and approval logs.
At usage-based companies, the controller must tie usage data to billing and revenue every month.
The controller usually reports to the CFO, or to the CEO at companies without a CFO.
The job in one paragraph
A controller runs the accounting function and is accountable for the accuracy of the company's financial statements. That means owning the close, the general ledger, revenue recognition, internal controls and the relationship with auditors. At a startup, the controller is often the most senior accountant. The CFO, CEO and board rely on them to say the numbers are right.
What a controller owns, and the proof an auditor will ask for
Lists of duties are easy to find. The more useful view is what each responsibility looks like when someone tests it.
Area | What the controller owns | What an auditor or board will ask for |
|---|---|---|
Close | Close calendar, checklist, review and sign-off | Dated checklist, locked periods, list of post-close entries |
Revenue | Policy under ASC 606, contract review, revenue schedules | Contract-to-revenue tie-out and support for judgments |
Balance sheet | Reconciliation of every material account | Signed reconciliations with aged reconciling items |
Controls | Approvals, segregation of duties, system access | Evidence controls ran, such as approval logs |
Reporting | Financial statements and flux commentary | Explanations that trace to transactions |
Systems | Chart of accounts, integrations, posting rules | Documented mappings and change history |
A controller's month
The calendar below is typical for a startup closing in eight business days. Day 0 is the last day of the month.
Timing | Focus |
|---|---|
Days −3 to 0 | Confirm cutoffs; collect usage and cloud cost data; pre-book recurring accruals |
Days 1–3 | Review reconciliations; post usage revenue, hosting and payroll accruals |
Days 4–6 | Revenue and deferred revenue review; flux analysis on P&L and balance sheet |
Days 7–8 | Final review, lock the period, deliver statements to the CFO or CEO |
Rest of month | Policy work, audit requests, system fixes, pricing and contract reviews |
Worked example: the usage tie-out
Illustrative only. Fieldnote AI, a fictional Series B company with usage-based pricing, prices usage at $0.05 per credit. The controller's most important revenue control is a tie-out between three sources.
Source | Credits | Value at $0.05 |
|---|---|---|
Usage database: credits consumed in October | 2,000,000 | $100,000 |
Billing system: credits invoiced for October | 1,920,000 | $96,000 |
Difference | 80,000 | $4,000 |
Investigation shows the 80,000 credits are late-arriving events that reached the usage database after the billing run. The service was delivered in October, so revenue belongs in October. The controller books the difference and asks engineering to fix the billing cutoff.
Account | Debit | Credit |
|---|---|---|
Unbilled accounts receivable | $4,000 | |
Usage revenue | $4,000 |
A $4,000 gap is small. The same unexplained gap repeated monthly and growing with volume is exactly what an auditor will sample.
What changes for controllers at usage-based and AI companies
Revenue depends on data engineering. The controller needs read access to usage data and a monthly completeness test.
Cost of revenue is variable. Inference and hosting costs move with usage, so gross margin needs consistent tagging and accruals.
Credits and commitments. Prepaid credits create deferred revenue and breakage questions under revenue recognition rules.
Pricing changes are accounting events. New plans can change performance obligations and need review before launch.
Health metrics a controller should track
These measure the accounting function itself, not the business. A board rarely asks for them, but they predict audit pain.
Metric | What it tells you | Healthy direction |
|---|---|---|
Business days to close | Whether the process is predictable | Stable or falling |
Entries posted after lock | How often reported numbers change | Close to zero |
Unreconciled balance sheet accounts | Hidden errors waiting for the audit | Zero material accounts |
Usage-to-billing variance | Revenue completeness for usage pricing | Small, explained, not growing |
Aged reconciling items over 60 days | Problems carried instead of fixed | Falling |
Mistakes new startup controllers make
Fixing history before the present. Stabilize the current close first, then clean up prior periods.
Owning revenue policy without seeing usage data. Ask for direct read access early.
Accepting metric definitions from the pitch deck. Reconcile board metrics to the ledger before the next meeting.
A first-90-days checklist for a new startup controller
Map every system that posts to the ledger and who owns it.
Reconcile every balance sheet account as of the last closed month.
Write the revenue policy and test it against the five largest contracts.
Build a dated close checklist with owners and reviewers.
Document key internal controls: approvals, access, journal entry review.
Agree on metric definitions with the CFO or CEO so board numbers match the ledger.
How Quanta supports controllers
Quanta's in-house accounting team keeps the ledger, and integrations pull from the usage database, Stripe, Ramp, Rippling and cloud bills. Controllers get current numbers built around how the company charges, with COGS lines tagged. They can ask questions of the books in Claude through the Quanta MCP and trace each answer to journal entries.
Quanta perspective
At usage-based companies, the controller's hardest control sits outside the ledger: proving usage data is complete. A clean tie-out from usage to billing to revenue each month does more for audit readiness than any number of extra review steps.
Frequently asked questions
Who does a controller report to?
Usually the CFO. At earlier-stage companies without a CFO, the controller often reports to the CEO.
Does a controller need a CPA?
It is not legally required, but many companies prefer it, especially before an audit or when the controller owns technical accounting judgments.
What is the difference between a controller and an accounting manager?
An accounting manager runs daily accounting and the team. The controller owns policy, sign-off, controls and the audit relationship.
When does a startup need a controller?
Typically when it needs accrual-basis statements for investors, faces its first audit, or has revenue that needs recognition judgments.
Is a controller the same as a comptroller?
The roles are similar. Comptroller is more common in government and nonprofit organizations.