How to Use Norm.dist in Excel

What this does

NORM.DIST returns the probability that a normally distributed value falls at or below a point; NORM.INV takes a probability and returns the corresponding value. The cumulative argument is the one that catches people — TRUE gives the running probability you almost always want, FALSE gives the density curve height, which is only useful for plotting the bell shape. Their standardised siblings NORM.S.DIST and NORM.S.INV assume a mean of 0 and a standard deviation of 1, so they take z-scores directly. The assumption of normality is doing real work here and deserves a check before the numbers are trusted. The same idea underpins a lot of everyday Excel work, so the few minutes spent getting it right here pay back across every sheet you build afterwards. Treat it as a pattern, not a one-off, and it stops being something you look up and starts being something you reach for. For “use norm.dist in excel”, the reliable version is a short checking loop, not just the first command that appears to work. Run it on a deliberately small range first, watch how the affected cells change, and only then apply the same setup to the full sheet. When a formula is involved, keep the inputs labelled beside it, reference cells instead of typing values, and apply number formatting only after the result checks out. That is what makes a workflow that saves repeating the same clicks every week useful in real work: repeatable, auditable, and not dependent on memory or luck.

A worked example

The share of deliveries arriving within 5 days when the mean is 4.2 and the deviation 1.8: =NORM.DIST(5, 4.2, 1.8, TRUE) returns about 0.67. The service level that 95 % of orders meet: =NORM.INV(0.95, 4.2, 1.8) returns roughly 7.2 days. Plotting the bell curve itself needs the density form with FALSE. These two turn a mean and a deviation into service levels and thresholds, which is what capacity and SLA planning actually asks for. Check the referenced cells, argument order and result type in your workbook. Start with the worked example before changing an input, then compare the changed result with the calculation you expected. An error value or a result of a different type is a reason to inspect the inputs and arguments.

In Google Sheets

Google Sheets support for this task has not been verified. Check the function, arguments and workflow in the target product before transferring the example. Matching formula notation does not establish identical behaviour. Nothing on this page is behind a login or a download: the exact answer is at the top, and the detail below it is there for when you need it. That is the whole promise here — the answer first, and just enough context to make it stick. For “use norm.dist in excel”, keep the input cells and the result visible while you check the formula in Excel. Follow the worked example and change one input at a time. The steps explain the workbook calculation; this page does not run a live calculator for that task.

Common mistakes

• Passing FALSE for cumulative and reading the result as a probability; that is the density, not a probability.
• Applying it to visibly skewed data, where the normal assumption misstates the tails badly.
• A standard deviation of zero or negative, which returns #NUM!.

Frequently asked questions