Common Size Mode
This article explains common size mode for charts and tables in Model Reef.
You will learn:
What common size mode does.
How it is applied to P&L, Balance Sheet and Cashflow views.
When to use it for analysis and communication.
Common size mode expresses series as percentages of a chosen base rather than absolute values.
What common size mode is
In common size mode, values are shown as a proportion of a base metric, for example:
P&L lines as a percentage of Revenue.
Balance Sheet items as a percentage of Total Assets.
Cashflow lines as a percentage of total cash inflows or outflows.
This makes it easier to compare structure across periods or scenarios, even when absolute sizes differ.
How common size calculations work
When you enable common size:
Each line item in a period is divided by the base value for that period.
The result is expressed as a percentage.
If the base is zero in a period, the behaviour may be to show blanks or zero, depending on implementation.
The underlying absolute values of the model do not change, only the display.
If the base is zero for a period, percentage results depend on the system implementation and may appear as blanks or zeros.
Uses of common size analysis
Common size mode is particularly useful for:
Comparing cost structure between companies or scenarios.
Tracking margin structure changes over time.
Understanding how assets and liabilities mix evolves as the business grows.
It can reveal shifts in composition that are not obvious from raw numbers.
Best practice
When using common size mode:
Always state clearly what the base is (for example "Percent of Revenue").
Combine with absolute charts elsewhere so users do not lose sense of scale.
Use it to highlight structure and mix, not as the only view of performance.
Used well, it complements rather than replaces absolute analysis.
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