---
id: freeing-space.why-are-there-two-scales-on-the-chart
url: https://storagestudio.us/faq/freeing-space/why-are-there-two-scales-on-the-chart
category: "Freeing up space"
subcategory: "Storage Profile, charts and Home"
question: "Why does the storage chart have two different scales?"
alt_questions:
  - "Dual axis storage chart"
  - "Internal and external drive on one chart"
  - "Why don't the two lines share a scale?"
  - "Chart axis left and right"
  - "Two y axes Storage Studio"
short_answer: "Your built-in and fast drives are often very different sizes, so each gets its own colour and scale; otherwise the smaller drive's changes would be flattened."
tags: ["charts", "dual axis"]
related: ["https://storagestudio.us/faq/freeing-space/what-are-the-storage-charts", "https://storagestudio.us/faq/freeing-space/how-do-i-zoom-the-storage-chart"]
applies_to: "all"
last_reviewed: 2026-10-01
---

# Why does the storage chart have two different scales?

So both drives read clearly. Your built-in drive and your fast drive often differ a lot in size — say a small internal drive and a much larger external one — and on a single scale the smaller one would be flattened into a line along the bottom.

Each drive gets its own colour and its own scale, so changes on either are easy to see. Hover a point to read the exact value. See [What do the storage charts show?](https://storagestudio.us/faq/freeing-space/what-are-the-storage-charts)