Fixed Costs, Variable Costs, and Why Utilization Changes Everything

Many equipment owners experience a frustrating reality: the same machine, doing the same type of work, can feel profitable one year and unprofitable the next—even when rates haven't changed much.

This is not bad luck. It is almost always a utilization problem.

To understand why, you need to understand the difference between fixed costs, variable costs, and how utilization acts as a multiplier on both.

Operators often say: "I don't understand why this machine used to make money," or "Nothing major changed, but margins disappeared."

What usually changed was not the machine—it was how many productive hours or miles were spread across the same fixed costs. Without understanding this relationship, owners chase symptoms instead of causes.

Fixed costs exist whether the machine runs or not: depreciation (economic), insurance, taxes, storage, and a portion of overhead. These costs are time-based, not usage-based.

Variable costs change with use: fuel, routine maintenance, repairs, and wear items (tires, tracks, undercarriage). These costs are activity-based and usually easier to "feel" day to day.

Most small businesses instinctively focus on variable costs because fuel feels expensive, repairs feel painful, and parts invoices get attention.

Fixed costs fade into the background because they are paid monthly or annually, don't spike suddenly, and don't feel connected to any single job.

High-performing companies understand that fixed costs are often the bigger threat—not because they are larger, but because they are invisible at the job level.

Utilization answers a simple but critical question: How many productive units am I spreading my fixed costs across?

For equipment, that unit is usually hours (skid steers, excavators) or miles (trucks, trailers). Fixed costs do not shrink when utilization drops. They concentrate. This is the lever most operators underestimate.

When utilization is high, fixed costs are diluted, cost per hour decreases, and margins appear healthy. This creates a dangerous illusion: "This machine is cheap to run."

In reality, it is not cheap—it is well utilized.

When utilization falls, fixed costs are spread across fewer hours or miles, cost per unit increases sharply, and margins erode quickly.

Nothing about the machine changed. The economics did.

Assume a skid steer with annual fixed owning costs of $3,600 (insurance, tax, storage).

Scenario A — Healthy Utilization: 1,000 hours/year. $3,600 ÷ 1,000 = $3.60/hr.

Scenario B — Reduced Utilization: 700 hours/year. $3,600 ÷ 700 = $5.14/hr.

The machine did not get worse. It simply ran less. That $1.54/hr difference flows straight into margin loss if pricing does not change.

A common assumption is: "If I run the machine less, depreciation goes down." Economically, this is false.

Depreciation per hour is determined by total usable life and total recoverable value. If the machine has 6,000 useful hours, every hour used still consumes the same slice of value—even if those hours are spread across more years.

Low utilization does not save depreciation. It delays replacement while still consuming value.

Variable costs usually feel easier to manage because they move with usage and are visible on invoices. However, they can still mask problems if not normalized.

For example, fuel spending may drop because hours dropped—but cost per hour may actually rise due to inefficiency. High performers track both total cost and unit cost, but make decisions using unit cost.

High-performing companies do not treat utilization as an accident. They define minimum acceptable utilization thresholds. Below those thresholds, they:

• Raise rates
• Reduce fleet size
• Subcontract work
• Park or sell equipment

A machine can be busy, cash-flow positive, and still economically unprofitable.

If utilization is below the level required to absorb fixed costs at the current rate, the business is quietly eroding its capital.

High performers would rather run fewer hours at the right rate than run many hours below economic reality.

Understanding utilization requires separating fixed and variable costs, converting them to unit rates, and seeing how changes affect break-even.

TRUEHOUR makes this relationship visible: fixed costs are clearly separated, utilization is explicit, and break-even updates as usage changes.

Fixed costs don't care how busy you feel. They care how many productive units they are spread across.

Utilization is the multiplier that turns good equipment into great equipment—or good equipment into a silent loss. Operators who understand this stop blaming the machine and start managing the system.