Growth capacity is a score out of 100 for whether the business could take on more work right now without breaking.
It is deliberately not a measure of whether more work is available. Demand is the easy half; surviving the growth is the half that closes businesses.
What goes into it
Three things, and they are the three that fail first when a business grows faster than its finances.
Cash runway — three months or more is the point where this stops holding you back. Growth consumes cash before it produces any: materials and labour go out weeks before the invoice comes in.
Strategic reserve — a buffer that is not committed to anything. Growth surfaces surprises, and a business with no slack has to fund them by delaying something else.
Profit margin — around 15% or better. This one carries the most weight, and for a hard reason: growing an unprofitable business does not fix it. It multiplies it.
The counter-intuitive part
A low score during a busy period is not a contradiction. Busy and capable of growing are different states, and the gap between them is exactly what this measures.
The classic failure is a business with a full calendar, thin margins and no cash, taking on a large job that requires materials up front. The work is real, the revenue is real, and the business runs out of money in the middle of it.
What to do with a low one
Fix the weakest component rather than the score. Margin is usually both the largest contributor and the slowest to move, which is the argument for starting on it before the growth rather than during it.