Billable hourly cost: the formula to stop selling at a loss

Quick answer. Your billable hourly cost equals total annual costs divided by your genuinely productive hours, plus a target margin. A full-time year holds 1,607 legal working hours (article L3121-27 of the French Labour Code), yet rarely more than 1,100 to 1,400 billable ones: that reduced denominator is what so often turns a sale into a loss.

An hourly rate quoted at 60 euros can actually lose you money on every engagement. The trap is almost always the same: costs are spread over paid time, while you only invoice a fraction of that time. At Hayot Expertise, we regularly see consultants, agencies and tradespeople set a rate that covers their costs on paper, but collapses the moment unsold hours are factored in.

This applies to every service activity. Whether you sell consulting days, production hours or an average day rate, the logic is identical: until you know your genuinely productive hours, your price is a guess, not a management decision.

The hourly cost of production is not your salary divided by 35. It is the full cost of running your activity, spread over the hours you actually bill.

The legal working time is 35 hours per week for a full-time employee, or 1,607 hours per year for a full-time role (article L3121-27 of the French Labour Code). A director under an annual day-rate agreement can work up to 218 days per year (articles L3121-58 and following). But none of these hours is fully billable.

Between prospecting, quotes, invoicing, training, accounting and quiet periods, a substantial share of time is never sold. Confusing paid time with billable time is the most common and most costly mistake.

The underestimated risk: the denominator, not the numerator#

Most providers polish the numerator (their costs) and neglect the denominator (their sellable hours). Yet the denominator decides. Moving from 1,607 to 1,200 billable hours mechanically raises the hourly cost by more than 30 percent. The same cost base spread over fewer hours lifts the break-even floor far faster than expected.

Start from available time, then subtract everything that is not sellable.

1. Base hours: 1,607 for a full-time role (or your working days multiplied by hours per day).
2. Paid leave: an employee accrues 2.5 working days per month, i.e. 30 working days, or 5 weeks per year (article L3141-3 of the French Labour Code).
3. Public holidays not worked.
4. Non-billable time: prospecting, quotes, training, admin, accounting, unrecharged travel.
5. Bench time or quiet periods specific to your activity.

The balance is your productive hours. As a rough indication, many service activities run around 1,100 to 1,400 billable hours per year. This is not an official standard: it is a management order of magnitude, to be recalibrated against your real data. The same logic underpins any calculation of a product's cost price, where the unit of measure drives the result.

The hourly cost of production must absorb your full cost base, not just your pay.

Neutralise VAT: collected VAT is never revenue, it is owed to the State. To isolate what truly belongs to you, see how to handle VAT on your invoices before any margin calculation.

Once both blocks are gathered, the formula is simple.

Hourly cost of production = total annual costs / genuinely productive hours.

Billable hourly cost = hourly cost of production x (1 + target margin).

The average day rate follows by multiplying the billable hourly cost by the sellable hours in a day (rarely 8, more often 6 to 7).

Worked example (illustrative, to recalibrate)#

Take an independent consultant. The figures below illustrate the method, not a market standard.

In this example, billing 60 euros per hour means selling 15 euros below production cost: every hour sold deepens the deficit. The right reflex is to distinguish gross margin from net contribution to check what really remains after direct costs are allocated.

The target margin is not a bonus. It funds corporate tax, investment and a safety cash buffer. For a company subject to corporate income tax, the standard rate is 25 percent, with a reduced rate of 15 percent up to 42,500 euros of profit under conditions (article 219 of the French General Tax Code). A zero margin means tax due with no cash to cover it.

We advise thinking in three layers: cover costs, fund tax, generate reinvestable profit. A rate that only covers the first layer is not a break-even rate, it is a survival rate.

Recently, the director of a small service agency came to us after two tight years despite a full order book. The diagnosis was immediate: a day rate built on 1,600 hours, while the team actually billed 1,150. The gap between quoted rate and real cost was enough to absorb the entire result.

Two levers fixed it: cutting non-billable time through better organisation, and recalibrating the rate on hours actually sold. This is exactly the kind of trade-off we handle within an outsourced finance function.

Receivables: the forgotten lever of hourly profitability#

A sound rate is worthless if invoices are paid late. Between professionals, the default term is 30 days, and the maximum contractual term is 60 days from invoice issue, or 45 days end of month by option (articles L441-10 to L441-16 of the French Commercial Code). Beyond that, late-payment penalties are due automatically; in the first half of 2026, the usual rate stands at 12.15 percent, plus a flat 40-euro recovery indemnity per invoice. Meeting these terms protects your hourly rate as much as the calculation itself: rely on a client collection procedure and anticipate cash with a 13-week cash flow plan.

When a client negotiates, two legitimate options compete.

Our reading: cutting the rate is a visible, immediate decision, but reducing non-billable time is almost always more profitable in the medium term, because it lowers the hourly cost of production itself. Track these trade-offs with the right financial pilot indicators.

• Phantom hours: never count a full day as billable. A realistic day rate rests on 6 to 7 sellable hours, not 8.
• VAT and social contributions: include loaded pay, not net. For a self-employed director, personal contributions are part of the cost.
• Seasonality: an hourly cost based on a full year must account for quiet spells. Smoothing over 12 months can hide an empty quarter.
• Capital equipment: for VAT-exempt activities, input VAT on equipment is not recoverable, which raises the hourly cost; this is a sensitive point for a dental practice and other healthcare professionals.

• Micro-entrepreneur: no VAT recovery or classic deductible costs, but the flat allowance does not reflect your real costs. Compute your hourly cost anyway to check the scheme is not hiding a loss.
• Company under corporate tax: build profit tax into your target margin, otherwise you bill your own tax at your own expense.
• VAT-exempt activities (certain healthcare professions, training under conditions): non-recoverable VAT on purchases inflates the hourly cost of production.
• Teams: compute an hourly cost per profile; a single average rate hides loss-making profiles.

To keep these calculations reliable over time, rigorous bookkeeping and review provides the exact cost base, and building your forecast lets you test several rate scenarios before committing.