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AI-Powered Forecasting Template
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Copilot + Python in Excel — companion workbook for the AI Stack Base guide
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What's inside this workbook
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1) Historical Data — 24 months of sample retail sales you can replace with your own numbers.
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2) Forecast (Excel Formulas) — a working, auto-calculating 6-month forecast built with FORECAST.ETS, no add-ins required. This updates live in Excel and LibreOffice.
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3) Python in Excel (PY Library) — ready-to-paste Python code blocks for the =PY() cells that ship with Microsoft 365's Python in Excel feature, covering trend decomposition, Holt-Winters/ETS, and seasonality charts.
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4) Copilot Prompt Cheat Sheet — the exact prompts referenced in the article, organized by task.
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5) Accuracy Comparison — an illustrative example comparing a traditional formula forecast against a Copilot + Python workflow, for Q4 inventory planning.
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Important: about the =PY() cells
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Python in Excel is a Microsoft 365 cloud feature — the Python code only runs inside a real Excel session connected to Microsoft's runtime, on Current Channel / Beta Channel builds. It cannot be pre-calculated or embedded as a working formula in a plain .xlsx file outside that environment.
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That's why this workbook gives you two parallel tracks: a formula-only forecast (tab 2) that works everywhere right now, and a Python code library (tab 3) with tested snippets you paste directly into a =PY() cell once you open this file in Excel with Python enabled.
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To enable it: Excel > Insert tab > Python (or type =PY( in a cell). If you don't see it, go to File > Options > Insert Formula Options and check your Microsoft 365 channel — it's rolling out gradually as of 2026.
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Color legend
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 Blue text
Hardcoded input — safe to edit
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 Black text
Formula — do not overwrite
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 Yellow fill
Key assumption to review before publishing/using
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How to use this with the article
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Replace the sample data on tab 2 with the reader's own monthly figures, keep the formulas, and the forecast + chart recalculate automatically. This is the file meant to be offered as the lead magnet / paid template referenced in the E1 article.
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