Start with the spreadsheet you already use
A design quote often starts as a useful working spreadsheet and ends as an afternoon of copying, formatting and checking. The opportunity is to turn that existing information into a consistent client document without asking the designer to maintain the same numbers in two places.
At Marais Home, our own retail and interior design business, we built a workflow that takes an Excel workbook uploaded in ChatGPT and produces a branded, room-by-room PDF. Code handles the calculations. This guide explains that approach and how another studio could adapt it; it is not a claim that every spreadsheet will work without setup.
The first decision is scope. Automating document preparation does not automatically handle client approval, purchasing, invoicing or payments. Choose one repeatable handoff: an approved selection spreadsheet becomes a draft quote for a person to review.
Give each row an unambiguous meaning
Start with room, item description, quantity, unit price and inclusion status. Add a stable item reference if revisions are common. Keep internal cost and client price in separate fields, and explicitly choose which fields may appear in the client document. A hidden spreadsheet column is not a reliable rule for protecting internal information.
Decide what counts as a line item. A heading such as Living Room, an allowance and a purchased sofa should not all be interpreted the same way. Define how room headings, blank rows, optional items, freight and notes are represented. Preserve the designer’s room order instead of sorting everything alphabetically.
At Marais, the quote workflow has explicit rules for excluding tabs marked on hold or additional scope by default. Your studio may need different rules. Write them down and show the included rooms in the review, so an exclusion cannot disappear unnoticed.
A small worked example
Fictional example: a living room contains two accent chairs at a client price of $750 each and one side table at $300. A rug priced at $900 is an optional selection. The included merchandise subtotal is $1,800. The rug should appear in a clearly separate optional section or remain excluded, according to the studio’s chosen format.
The calculation layer multiplies quantity by unit price, adds included lines and applies any explicitly configured adjustments. Taxes and delivery charges depend on the studio’s approved rules and the transaction; this example deliberately omits them. Missing charges should be identified as unresolved rather than silently entered as zero.
If the client selects the rug, update the source and generate a new version. The merchandise subtotal becomes $2,700. Keeping a version date and source workbook makes it possible to explain why the document changed without searching through several manually edited PDFs.
Let AI help with interpretation; let code calculate
AI can help identify inconsistent column labels, draft readable item descriptions or flag an unclear note. Those interpretations should be reviewable. The same input and pricing rules should always produce the same arithmetic, regardless of how a request is phrased in chat.
Build explicit stops for missing prices, invalid quantities, duplicate item references and unfamiliar workbook layouts. An empty cell must not become a free item. A quantity written as a note such as two pairs needs clarification before calculation. The useful output in those situations is a short exception list, not a plausible-looking finished quote.
Review the document, not just the totals
A mathematically correct document can still be wrong. Check that long descriptions fit, every included room appears, optional items are clearly identified and private fields are absent. Inspect every PDF page for clipped rows, awkward page breaks and missing notes.
Start with a completed, anonymized project and compare the generated result with the approved quote. Include at least one deliberate exception before relying on the workflow for new work. Then use it on a live draft with the same human approval you already require.
- Choose one workbook format and document its inclusion and pricing rules.
- Run a small sample containing ordinary items, an option and a missing value.
- Compare source rows, calculated totals and every rendered page.
- Record corrections in the workflow before expanding to other quote formats.