An Excel formula is any expression, starting with an equals sign, that you write to calculate a value (for example, =A1+B1), while a function is a ready-made formula built into Excel, such as SUM, VLOOKUP, IF or XLOOKUP, that performs a specific task. All functions are technically formulas, but not every formula uses a function. Beginners should master basic arithmetic operators first and then move to functions like SUMIF, IFERROR and INDEX-MATCH.

Excel's own Formulas tab groups every built-in function by category (financial, logical, text, date, lookup and more) and shows the syntax as you type. A faster way to learn is to work through a curated list of Excel formulas with examples and apply each one to a real dataset, such as a sales register or monthly budget, so you can see exactly how the output changes with your own numbers.

There is no dedicated percentage button, so you build it with division. The most common Excel formula for percentage is =part/total, for example =B2/C2 shows B2 as a share of C2, which you then display as a percentage using the % button on the Home tab. For percentage growth, use =(new value - old value)/old value.

The Excel formula for subtraction is =A1-B1, where you simply place a minus sign between cell references, while the Excel formula for multiplication uses the asterisk, as in =A1*B1. You can combine both in one expression, such as =(A1-B1)*C1, and use brackets to control the order of calculation.

Microsoft Excel data analysis is the process of cleaning, organising and interpreting data inside Excel so it supports a decision, typically using formulas, PivotTables, charts, conditional formatting, Power Query and the Data Analysis ToolPak. Businesses rely on it for sales trends, budget-versus-actual comparisons, KPI dashboards and forecasting, especially when the data is too large to review manually.

Go to File > Options > Add-ins, choose "Excel Add-ins" in the Manage box, click Go, tick "Analysis ToolPak" and press OK. A "Data Analysis" button then appears on the Data tab, giving you ready-made statistical tools such as Descriptive Statistics, Histogram, Regression, Correlation and t-Tests without writing any formulas.

List all fixed and variable cost heads in one column with their amounts and periods beside them, then use SUM and SUMIF to total them by category, department or month. Build a variance section that compares budgeted versus actual costs using a simple subtraction and a percentage-change formula, and finish with a PivotTable and chart so the biggest cost drivers are visible at a glance.

Pick an Excel data analysis course that is hands-on with real datasets rather than theory-only, and that covers formulas, PivotTables, charts, data cleaning with Power Query and ideally an introduction to Power BI, since most reporting roles expect both tools. Live training or doubt-solving support is a big advantage at the beginner stage, because most learners get stuck on practical, file-specific problems that pre-recorded videos rarely resolve.

You can find Excel data analysis projects for practice on public dataset platforms, in downloadable practice workbooks, or by analysing your own bank statement, expenses or sales data. A good progression is a sales dashboard with PivotTables and slicers, a monthly budget tracker, an inventory or attendance analyser, and a KPI report that refreshes automatically when new data is pasted in.

Yes. Popular AI chatbots let you upload a spreadsheet on their free tiers and ask for trends, summaries or formula help, and Excel's built-in Copilot assistant can analyse data too, though its availability depends on your Microsoft 365 plan. A practical free workflow is to ask the AI to generate or explain a formula, paste it into Excel and refine it, which speeds up cleaning, formula writing and chart ideas without a paid subscription.

If you know the password, open the Review tab, click "Unprotect Sheet" (or "Unprotect Workbook" for file-level protection) and enter it. If you have forgotten it, remember the difference: normal sheet protection only locks editing and can be removed with well-documented methods, whereas a file encrypted through "Encrypt with Password" genuinely needs the password or a recovery tool. Always work on a copy so the original file stays safe.

Start with the two foundations, calculated columns versus measures and row context versus filter context, because nearly every later DAX confusion traces back to them. Then learn the core functions in order: basic aggregations like SUM, AVERAGE and COUNT, then CALCULATE, then filter functions such as FILTER and ALL, and finally time intelligence like TOTALYTD and SAMEPERIODLASTYEAR. The most effective Power BI DAX practice is rebuilding a real sales or finance report and questioning why every number changes as you add slicers.

DAX (Data Analysis Expressions) is the formula language of Power BI, used to build calculations that visuals cannot do on their own, such as year-to-date sales, profit margin %, running totals, same-period-last-year comparisons and dynamic rankings. It powers measures and calculated columns, which is what turns a static report into an interactive dashboard that responds to slicers and filters.

Most Power BI DAX formulas follow one pattern, function name, opening bracket, table or column, conditions, closing bracket, so a handful of worked examples makes the rest easy to read. Keep a personal reference of Power BI DAX functions with examples grouped by purpose (aggregation, filtering, time intelligence, text and logical), and test each snippet on a small table in Power BI Desktop so you can immediately see how filter context changes the result.

The most frequently asked Power BI DAX interview questions cover measures versus calculated columns, row context versus filter context, how CALCULATE works, SUM versus SUMX, the behaviour of ALL, ALLEXCEPT and REMOVEFILTERS, and time intelligence such as YTD or month-on-month growth. Interviewers often give a live task like "write a measure for last month's sales", so practice writing DAX on a sample model instead of only reading answers.