Then adjust weights manually:

You might ask: if powerful libraries like TensorFlow or PyTorch exist, why bother with spreadsheets? The answer lies in .

Alternatively, you can use the =PY function to manually write code that defines layers ( nn.Linear , nn.ReLU ) and trains the model using data referenced directly from your Excel ranges. 2. The Traditional Way: Building from Scratch (No-Code)

By building neural networks in MS Excel, you're not only expanding your skillset, but also contributing to the evolution of data analysis and machine learning. So why not give it a try? With a little creativity and practice, you can build a neural network in Excel and unlock new insights into your data.

Formula: =(A1_Activation * $I$2) + (A2_Activation * $I$3) + $I$4 Formula: =1 / (1 + EXP(-Z3_Cell))

If you are running a Microsoft 365 environment with integrated natively, you can bypass manual matrix formulas entirely while keeping your data in the spreadsheet. Typing =PY in a cell unlocks access to standard data science libraries like scikit-learn . You can load your Excel spreadsheet rows into a Pandas DataFrame and train a neural network using a few lines of code:

Create a summary cell at the top of your sheet that calculates the by averaging the loss column: =AVERAGE(Loss_Column) . Your goal is to drive this number as close to zero as possible. Step 4: Backpropagation (The Math Engine)