Generating a spreadsheet is easy; generating one whose formulas are correct, whose sheets reference each other properly, and which someone else can audit is not. Claude Opus 5 is genuinely good at the second version — multi-sheet workbooks with non-trivial formulas rather than a flat table pretending to be a model.
This page is written for finance teams, analysts, and operators who live in Excel. If you want the model overview first, start with the complete Claude Opus 5 guide.
| Best effort level | high |
| Context available | 1M tokens — enough for real working material, not just snippets |
| Cost | $5 per million input tokens, $25 per million output |
Why Claude Opus 5 suits spreadsheet and financial modelling
- It produces real
.xlsxfiles with live formulas, not screenshots or pasted values. - It handles multi-sheet structure — assumptions, calculations, and outputs kept separate the way a reviewable model should be.
- It can follow a template or house style when you give it one.
- It can read a workbook back and explain what a formula chain does, which makes it useful on models you inherited.
A workflow that works
- State the structure first — which sheets, what drives what, and where the assumptions live.
- Give it your template if you have one. It follows an explicit spec precisely; left open, it picks its own conventions.
- Ask for assumptions on their own sheet, clearly labelled. This is the difference between a model and a black box.
- Spot-check the formula chain, not just the output number. Ask it to walk you through one column.
- Iterate in place. It edits existing workbooks; you do not have to regenerate from scratch to change one assumption.
Settings to start from
Set the effort level to high. Model-building is structured work that benefits from careful reasoning, but rarely needs the top of the ladder. high is a sensible default; step up for anything with unusual formula logic.
Leave adaptive thinking on — it is the default on Claude Opus 5, and turning it off introduces failure modes that are not worth the saving. See effort levels explained if you want to tune this properly.
What to watch out for
- Check the numbers. A model that looks right and is wrong is worse than no model. Verify the outputs against a case you already know the answer to.
- It is not financial advice, and it does not know your accounting policies unless you tell it.
- Ask for the length you want. Documentation tabs and written summaries tend to run long by default.
The verdict
Excellent for the first 80% of a model and for auditing someone else's. The last 20% — the judgement calls — is still yours.
If cost is the constraint, read how to cut Claude Opus 5 costs before downgrading — routing and caching usually beat switching models.
More on Claude Opus 5
Start with the complete Claude Opus 5 guide for the overview, or go deeper:
Ready to go deeper?
Read the full Claude Opus 5 guideFrequently Asked Questions
Can Claude Opus 5 create a real Excel file?
Yes. It generates genuine .xlsx workbooks with working formulas across multiple sheets, and it can edit existing files rather than only producing new ones. It can also read a workbook back and explain its formula chains — useful for a model you inherited.
Will the formulas be correct?
Usually, but verify. The reliable check is to run the model against a scenario whose answer you already know, and to have it walk you through one calculation chain in plain language. Treat it as a fast first draft from a capable analyst, not as an audited deliverable.
Can it match our company template?
Yes, if you give it the template or describe the conventions explicitly. Opus 5 follows a concrete spec precisely. Left to its own devices it will pick reasonable but generic conventions, which is rarely what a finance team wants.
