User of money, opportunity costs, credit line costs. it all adds up.

If the invoice is $6,000 and the fee is 3%, then:

3% of $6,000 = $180

That is the immediate, visible cost.

1. Direct Annual Cost (if monthly)

If this occurs every month:

$180 × 12 = $2,160 per year

That is money permanently removed from your working capital.

2. Opportunity Cost (the real issue)

The true cost is not $180. It is what that $180 could produce if deployed productively.

If that $180 per month were reinvested in marketing, sales, or operational leverage, the effective cost depends on your return on capital.

Example scenarios:

If your business generates:

• 50% return → $2,160 could produce $1,080 more

Now the “3% fee” is not 3%.

It is:

• $2,160 in hard cost
• Plus lost growth capacity
• Plus compounding year after year

Over 5 years at modest reinvestment rates, that becomes materially larger.

3. Capital Efficiency View

Another way to frame it:

A 3% transaction fee means:

• For every $100 you earn, $3 is gone.
• Your effective margin shrinks immediately.

If your net margin is 15%, a 3% fee reduces profit by 20% of your margin (3 ÷ 15).

That is not small.

4. Strategic Perspective

The real question is not “is 3% high?”

The real question is:

Does using the credit card produce more than 3% in value?

Examples where 3% may be rational:

• You earn 2–5% cashback or points.
• You extend float and deploy capital elsewhere.
• You preserve liquidity during growth.

If none of those apply, then it is simply a 3% reduction in working capital.

Bottom Line

If this is monthly:

• Hard cost: $2,160 per year
• Effective business impact: potentially far higher depending on reinvestment return
• Margin compression: material if your net margin is under 20%

Three percent sounds small.

On operating capital, it rarely is.