Billing clarity

What did your biggest retainer actually pay you per hour last month?

I asked a room of fractional executives this question once. Silence. Not because the math is hard. Because nobody had the two numbers in the same place.

By Jeff Lerner, fractional CMO and founder of SEVRL · July 2026

The two numbers that drift apart

Your retainer is the price of the engagement. Your effective hourly rate is what you actually earned once real hours are counted. When an engagement starts, they match. Six months in, they rarely do, and I've never once seen the drift favor the executive.

Here's how it went for me. I signed a client at $8,000 a month against roughly 20 hours. Great deal: $400 an hour. By month four I was on their Slack, in their Monday standup, reviewing things "real quick" between my scheduled blocks. My calendar said 34 hours that month. Nobody was being sneaky. The CEO was happy, I liked the work, and my effective rate had quietly dropped to $235. Below what I quote new clients. My best client had become my worst-paying engagement, and I found out by accident.

How to calculate your effective hourly rate

The formula is one division. The work is getting honest inputs.

• Take what the client actually paid you this month (not the contract number, the paid number).
• Divide by the hours you actually gave them: meetings, calls, prep, the Slack thread you answered from the school pickup line. Your calendar is the most honest record you have.
• Do it per client, monthly. The blended number across your whole practice hides exactly the problem you're looking for.

Then compare each result against your floor, the rate below which new work isn't worth taking. Most fractionals who do this exercise for the first time find one engagement sitting 30 to 40 percent under it.

Why spreadsheets never catch over-servicing

It isn't a discipline problem. It's an architecture problem. Revenue lives in your accounting tool or a spreadsheet you update when you invoice. Hours, if they're recorded anywhere, live in a time tracker or your calendar. The division that matters requires both numbers, in the same place, at the same time, and no tool in the standard consultant stack puts them there. So the question goes unanswered, not unasked.

Law firms figured this out decades ago. Every retainer has a burn rate and a person watching it. Fractional executives run the same economics without the watcher.

Making the number automatic

I built SEVRL around this exact problem. Your calendar feeds the hours (meetings sort themselves to clients by keyword). Your invoices feed the income. Every client shows an effective hourly rate that updates as the month fills in, next to a bar showing contracted hours burning down. When a client starts taking more time than they pay for, you see it in week two and can steer, instead of discovering it in month three and swallowing it.

Keep reading: why time tracking fails fractional executives · the real cost of sending an invoice