Who it's for: anyone in a SaaS or tech finance team who builds, inherits or reviews spreadsheets: reconciliations, schedules, forecasts and board pack workings.
What you'll get: a practical set of team spreadsheet standards, a build-and-review checklist, a worked accrual schedule with its journal, AI tips, and a one-slide pitch to get the standards adopted.
Reading time: about 11 minutes. Less time than untangling one hardcoded number in a 40-tab model.
Why spreadsheet standards matter
Most finance teams, however good their systems, still run on spreadsheets: the deferred revenue schedule, the accruals list, the ARR bridge, the cash forecast. When every file is built differently, review is slow, handovers are painful and errors hide in plain sight. A short set of shared standards makes every file faster to check and easier to trust, including by the auditors.
Key terms
- Hardcode: a number typed into a formula or a calculation cell instead of being pulled from an input or source.
- Input, calculation and output: the three jobs a cell can do. Inputs are entered, calculations work things out, outputs are what people read.
- Check cell: a cell that tests whether something agrees (for example, schedule total minus ledger balance) and shows zero or "OK" when it does.
- Version control: a consistent way of naming, saving and locking files so everyone uses the right one.
- Source data tab: a tab holding a raw, unedited export from a system, such as a trial balance or a billing report.
The standards, in one page
These are common standards many finance teams use. Adapt them, write them down, and apply them to every new or rebuilt file.
| Area | Standard | Why |
|---|---|---|
| Structure | Tabs in order: Cover, Inputs, Source data, Calculations, Outputs, Checks | Anyone can follow the flow from left to right |
| Cover tab | Purpose, owner, period, source systems, last updated, reviewer and date | The file explains itself without its author |
| Colour code | Inputs one colour (often blue text), formulas black, links to other files another colour, checks green/red | Reviewers see at a glance what's typed and what's calculated |
| No hardcodes | No numbers inside formulas. Rates, dates and assumptions sit in labelled input cells | Changes happen in one place; nothing is hidden |
| One formula per row or column | The same formula runs across a row or down a column, without one-off exceptions | Exceptions are where errors live |
| Source data untouched | Paste raw exports into source tabs and don't edit them. Adjustments happen in calculations, with a reason | The file can always be traced back to the system |
| Checks | Every file agrees to the ledger or source, with a check cell. A summary check on the cover tab | Errors announce themselves |
| Signs | One sign convention per file, stated on the cover (for example, credits negative as in the trial balance) | Avoids debits and credits flipping between tabs |
| Naming | File names like 2026-10 Accruals v02 PREP.xlsx and FINAL once reviewed | The latest version is obvious |
| Links | Avoid links to other workbooks where possible; paste values with a source note instead | Broken links are a classic close-week time sink |
| Formatting | Consistent number formats, no merged cells in calculation areas, frozen headers, no hidden rows or tabs without a note | Hidden things get forgotten |
| Locking | After sign-off, save as FINAL and protect it; changes go into a new version | The signed-off numbers stay signed off |
AI shortcut: Excel's and Google Sheets' built-in AI assistants, or another approved AI tool, can explain an inherited formula in plain English, suggest a simpler version of a nested IF, or write a formula from a description ("sum the amount column where the month is October and the status is Open"). Test the result on a few rows you've worked out by hand before trusting it.
Building a file: step by step
| Step | What "done" looks like | |
|---|---|---|
| ☐ | Start from the team template | Cover, Inputs, Source, Calculations, Outputs and Checks tabs in place |
| ☐ | Fill in the cover tab | Purpose, owner, period and sources completed before any numbers go in |
| ☐ | Paste source data as raw exports | Export date and system noted above each source table |
| ☐ | Put every assumption in the Inputs tab | No numbers typed inside formulas |
| ☐ | Build calculations with consistent formulas | Same formula across each row or column; no one-offs |
| ☐ | Add check cells | Total agrees to the ledger; all checks show zero |
| ☐ | Write a short note for anything unusual | Manual adjustments have a reason and a source |
| ☐ | Self-review, then pass to a reviewer | Preparer initials and date on the cover |
Reviewing a file: step by step
| Step | What "done" looks like | |
|---|---|---|
| ☐ | Read the cover tab and confirm the period and sources | The file is for the right month and the right entity |
| ☐ | Look at the checks first | All checks at zero, or explained |
| ☐ | Trace the output to the ledger | Key totals agree to the trial balance |
| ☐ | Spot-check formulas (Show Formulas, or trace precedents) | No hardcodes or broken ranges in a sample of rows |
| ☐ | Check inputs against evidence | Rates, dates and estimates supported |
| ☐ | Compare to last month | Big movements explained |
| ☐ | Sign off and lock | Reviewer initials and date; saved as FINAL |
AI shortcut: before review, ask an approved AI tool to scan the workbook (or a formula listing from it) for hardcoded numbers inside formulas, inconsistent formulas in a row, references to blank cells and links to other files. Treat its list as a starting point; the reviewer still traces the totals to the ledger.
Worked example: an accruals schedule built to standard
MonthEndClub Co Ltd, a fictional UK SaaS company, keeps its October 2026 accruals in a standard workbook.
Inputs tab: period end 31 October 2026; materiality for notes £1,000.
Calculations tab:
| Supplier | Basis | Nominal | Accrual £ |
|---|---|---|---|
| Cloud hosting | Usage dashboard, October | Hosting (cost of sales) | 18,500 |
| Contract developer | Timesheet: 12 days × £550 | Contractors | 6,600 |
| Audit fee | £24,000 annual fee ÷ 12 | Audit and accountancy | 2,000 |
| Legal | Lawyer's estimate by email | Legal fees | 3,400 |
| Total | 30,500 |
Note how the contractor line shows its workings (12 × £550 = £6,600) using a day count and day rate held as inputs, not a typed £6,600. The audit fee is the annual fee from the Inputs tab divided by 12.
Checks tab:
| Check | £ | Result |
|---|---|---|
| Schedule total | 30,500 | |
| Accruals balance in trial balance after posting (credit) | 30,500 | |
| Difference | 0 | OK |
Output: the journal
| Account | Dr | Cr |
|---|---|---|
| Hosting costs (cost of sales) | £18,500 | |
| Contractors | £6,600 | |
| Audit and accountancy | £2,000 | |
| Legal fees | £3,400 | |
| Accruals | £30,500 |
Debits total £18,500 + £6,600 + £2,000 + £3,400 = £30,500, matching the credit. A reviewer can see every basis, every input and the agreed balance on one screen, which is exactly the point.
Common mistakes and audit watch-outs
- "Plugs" to make a check work. A typed balancing figure hides the very error the check was meant to find.
- Edited source data. Once an export has been changed by hand, it can't be traced back to the system.
- Hidden rows and tabs. Old workings that still feed a total are a common source of errors.
- Ranges that don't extend. A SUM that stops at row 200 when new data reaches row 215. Tables or whole-column references help.
- Several "final" versions. If two files say FINAL, neither can be relied on.
- No evidence of review. Auditors look for who prepared and who reviewed, and when.
- Pasting AI formulas without testing. An AI-written formula can look right and be subtly wrong. Test it on rows you've worked out by hand.
- Uploading files to unapproved AI tools. Payroll, customer and financial data only goes into tools the company has approved.
Tools that can help
Excel and Google Sheets both have formula auditing tools (trace precedents, show formulas, error checking) and built-in AI assistants. Excel's Inquire add-in, where available, compares workbook versions. Accounting systems such as Xero, QuickBooks, Sage and NetSuite provide the clean exports that source tabs depend on. Tools help, but the standards only work if the team agrees and applies them.
Take it to your boss: one slide
Team spreadsheet standards
The problem: every file is built differently, so review is slow, handovers are hard and errors slip through.
Three changes
- One template with Cover, Inputs, Source, Calculations, Outputs and Checks tabs.
- Five non-negotiables: no hardcodes, untouched source data, check cells, clear names, sign-off on the cover.
- AI-assisted pre-review of formulas in approved tools, with the reviewer still tracing to the ledger.
| Risk | Control |
|---|---|
| Formula errors reach reporting | Check cells plus independent review |
| Wrong version used | Naming standard and locked FINAL files |
| AI mistakes or data leaks | Approved tools only; AI output tested |
How we'll measure it: share of key files on the template, review time per file, and number of post-close corrections caused by spreadsheet errors.
Key takeaways
- Agree a short, written set of standards and a template, and use them for every new or rebuilt file.
- Separate inputs, source data, calculations and outputs, and never hardcode inside formulas.
- Every file proves itself with check cells that agree to the ledger.
- Show who prepared and who reviewed, and lock the signed-off version.
- Use AI to explain, write and scan formulas; test its output and keep sign-off with people.
FAQs
Do we need to rebuild every old spreadsheet?
Usually not. A common approach is to apply the standards to new files, and to rebuild old ones when they next need major work, starting with the highest-risk files such as deferred revenue and the cash forecast.
Excel or Google Sheets?
Either works. The standards matter more than the tool. Many teams use whichever the rest of the business uses, so sharing and permissions are simpler.
Can AI review a spreadsheet for us?
It can do a useful first pass: flagging hardcodes, inconsistent formulas and broken references, and explaining complex formulas. It can't confirm the inputs are right or that the logic matches the accounting. A person still reviews and signs off, using company-approved tools only.
How many checks are enough?
At least one per output that agrees to the ledger or source system, plus internal checks where totals are rebuilt (for example, rows summing to columns). Too many checks that nobody looks at help no one; a single summary on the cover keeps them visible.
Related guides
- What to Automate First in Your Close
- The SaaS Finance Tech Stack, by Company Stage
- Keeping Audit-Ready Working Papers Every Month
- Accruals and Prepayments: A Practical Guide with Examples
More in Tech and Systems guides.
From the Club
Blue text for inputs. Black coffee for everything else. The Team Mug · The Washed Cap
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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.