Reading your margins.
Updated 16 October 2026
A single company-wide margin hides which parts of your business make money and which are carried. Here's how to see the truth.
A blended gross margin, one number for the whole company, feels like clarity, but it hides more than it shows. It can't tell you whether a product line is profitable, whether a location is carrying the rest, or whether a new service is worth the time it takes.
Margin by line reveals the truth
Margin by line changes that. When you break margin out by product, service, or location, patterns appear. You may find an offering everyone loves that only breaks even, a quiet line that funds the business, or a hire whose desk isn't paying for itself yet.
Why this is controller work
This is core controller work. It requires clean books first, you can't split margin you haven't categorized correctly. Then the analysis layer that turns categorized numbers into a decision you can act on.
How to build margin by line
- Decide the dimension first: product, service line, location or customer type. One dimension done properly beats three done partly
- Put direct cost with the revenue it produced, in the same period
- Allocate shared cost on a rule you write down, and keep the rule stable so months compare
- Leave overhead out of line margin and check separately that total line margin covers it
- Report the lines side by side every month, so a drift shows up as a trend
Questions we get asked
What is a good gross margin?
It only means something within an industry and a line. The useful comparison is your own line against itself over time, and against what the line needs to carry of overhead.
Why does my blended margin look stable while profit falls?
Because mix moved. A shift toward a lower-margin line holds the blended number roughly flat while the profit behind it drops.
How much detail is too much?
When nobody can explain an allocation rule from memory, the detail has stopped being useful.