Excel Formula Guides
Build a formula around a result you can check with a small example. Begin with sums or percentage change, then move to lookups and text conditions when your worksheet needs a decision or a match. If the result is wrong, use the troubleshooting guides to examine the references and inputs. AI can help explain a calculation, but keep a known result beside it so you can check the explanation.
Build a calculation
- Sum values that meet conditions
Choose SUMIF or SUMIFS for totals based on your criteria.
- Calculate percentage change
Compare an old value with a new one and format the result.
- Check whether a cell contains text
Combine a text search with an IF condition.
- ISNUMBER function reference
Check whether a formula result or cell value is a number.
Understand and repair formulas
- Find and fix circular references
Trace a calculation that refers back to itself.
- Explain a formula with AI
Break down a calculation and verify the suggested explanation.
All articles on this topic
17 articles
Excel Formula Errors: Find the Cause Before Hiding It
Diagnose six common Excel formula errors, check inputs and references, and fix the cause before using IFERROR to show a fallback....
Checkboxes in Excel: Build a Working Checklist
Add in-cell checkboxes in Excel, show task status, and count completed work with IF and COUNTIF. See version limits and the separate Form Controls method....
How to Change Case in Excel: Uppercase, Lowercase, and Proper Case
Learn how to change case in Excel with UPPER, LOWER, PROPER, Flash Fill, and Paste Special so you can safely replace text values....
Compare Two Columns in Excel
Learn how to compare two columns in Excel for matches, differences, duplicates, missing values, and case-sensitive text....
How to Find and Fix Circular References in Excel
Learn how to find a circular reference in Excel, trace the formula loop, fix common circular reference errors, and handle intentional iterative formulas....
How to Calculate Percentage Change in Excel
Learn the percentage change formula in Excel, including examples for increases, decreases, percentage formatting, and avoiding divide-by-zero errors....
The Karpathy Loop for Excel: How Autoresearch Changes the Way We Optimize Spreadsheets
Learn how Karpathy's autoresearch pattern — the AI experiment loop that ran 700 tests in two days — applies to Excel formula optimization, VBA macros, and AI-assisted spreadsheet workflows....
Claude for Excel Review: Best for Complex Models and Error Tracing?
Review Claude for Excel for complex models, error tracing, and careful workbook analysis, including the limits that still matter in beta....
ChatGPT for Excel: What It Does Well and Where It Still Needs Review
Review ChatGPT for Excel after the March 5, 2026 launch and see where it helps most with formulas, workbook analysis, and spreadsheet workflows....
How to Use =COPILOT in Excel
Learn how to use the =COPILOT function in Excel, what kinds of prompts work best in cells, and where this feature still needs careful review....
Can AI Fix Broken Excel Formulas? Real Tests With VLOOKUP, XLOOKUP, and SUMIFS
I tested whether AI can fix broken Excel formulas in real scenarios involving VLOOKUP, XLOOKUP-style logic, and SUMIFS errors caused by dirty data....
How to Use AI to Explain Excel Formulas Step by Step
Learn how to use AI to explain Excel formulas step by step, including how to verify the explanation and catch what the model still gets wrong....
Best AI for Excel Formulas: Copilot vs ChatGPT vs Claude
Compare Copilot, ChatGPT, and Claude for Excel formulas using the same prompt, the same workbook task, and the same verification standard....
How to Use Copilot in Excel for Formulas, Analysis, and Cleanup
Learn how to use Copilot in Excel for real workbook tasks such as formula writing, data cleanup, and quick analysis without trusting the first answer blindly....
How to Use XLOOKUP with Multiple Criteria in Excel
Learn how to use XLOOKUP with multiple criteria in Excel by combining Boolean logic or concatenation for cleaner, more flexible lookups....
How to Add Cells in Excel to Sum Up Totals Automatically
Excel's great for displaying data and even better at crunching numbers. Here's how to add cells in Excel to sum up totals automatically... Even when you change the numbers....
SUMIF and SUMIFS in Excel: Syntax, Examples, and Differences
Learn when to use SUMIF or SUMIFS in Excel, with working text, wildcard, and date examples—and see how their argument order differs....
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