AI in a spreadsheet
A 160-word SMS spam classifier whose weights live in Excel cells.
The classify sheet scores a text with SUMPRODUCT and
SEARCH; no macros, no Python, no server.
Download
The workbook has three sheets: classify (input + formula),
model (160 words × 2 weights) and readme.
Open in Excel, LibreOffice or Google Sheets. Replace cell B1 with an SMS; B4 is the verdict. Excel recalculates on load.
How the formula works
B2 (ham) = SUMPRODUCT(--ISNUMBER(SEARCH(model!A2:A161, B1)), model!B2:B161) B3 (spam) = SUMPRODUCT(--ISNUMBER(SEARCH(model!A2:A161, B1)), model!C2:C161) B4 = IF(B2>=B3, "ham", "spam")
The weights are Complement NB log-probabilities; higher is better.
SEARCH is a case-insensitive substring match, not the exact tokenizer:
formula accuracy is 90.6% on 1,115 held-out SMS, while the Python model is 90.9%.
A demo of a model small enough to live in a workbook, not a production filter.
The same model in other containers
the 2.2 KB QR URL · the 3.7 KB PDF model card · the Minimum-Bit Table · train your own · the 130 KB demos