What is the Five Whys technique?

The Five Whys is a root cause analysis technique developed by Sakichi Toyoda and refined within the Toyota Production System. By repeatedly asking 'Why?' — typically five times — you trace a problem back to its fundamental root cause rather than treating its symptoms.

When should you use the Five Whys method?

Use Five Whys when a problem keeps recurring, when current fixes only treat symptoms, or when a team needs to align on the real cause of an issue. It is widely used in lean manufacturing, agile retrospectives, DevOps incident post-mortems, and quality management.

Does Five Whys have to be exactly five questions?

'Five' is a rule of thumb, not a strict limit. You stop asking why when you reach a root cause you can actually act on and fix. This might take three iterations or seven, depending on the complexity of the problem.

What is the difference between Five Whys and a fishbone diagram?

Five Whys follows a single chain of cause-and-effect, making it fast and focused — ideal for straightforward problems. A fishbone diagram (Ishikawa diagram) maps multiple potential causes across categories simultaneously, which suits more complex problems with many possible contributing factors.

Is the FiveWhys tool free to use?

Yes. FiveWhys is completely free, requires no sign-up, and runs entirely in your browser. Your analysis is saved locally in your browser and you can export it as a PNG image or download it as a file.

FiveWhys — Free Five Whys Root Cause Analysis Tool

Map your problem's root causes as an interactive visual tree using the Five Whys technique. Completely free, browser-based, and no sign-up required.