Warning: Always verify a free spreadsheet against a hand calculation or known software (like a sample from your textbook) before using it on a real project. A single misplaced parenthesis in a formula can cause an unconservative design.
If you want to avoid downloading files altogether, consider Google Sheets templates designed for RC design. While not as powerful as Excel (no VBA), they work for basic beams. Search the Google Sheets Template Gallery for "Reinforced Concrete Beam Calculator." Warning: Always verify a free spreadsheet against a