Calculette Mauricette

Free work hours and overtime calculator built for French lab

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June 30, 2026 I built a free tool because my payslip never matched my own math

For months I tracked my hours in a notebook. Every payday I compared my notes to my payslip. The numbers rarely matched.

The problem was never my math. It was the format. My notebook used hours and minutes, like 7h45. My employer's payroll system used decimal hours, like 7.75. Nobody told me these two systems exist, and nobody told me how to convert between them correctly.

I started searching for a tool that handled this properly. Most calculators I found were generic time trackers built for the US or UK market. None of them understood French overtime rules, the 35 hour weekly threshold, or the 25 percent and 50 percent surcharge tiers that kick in after that.

So I built one myself. It is called Calculette Mauricette, and you can find it at mauricettecalcul.fr.

Here is what it does:

  1. Calculates daily and weekly work hours from simple start and end times

  2. Deducts unpaid breaks automatically

  3. Detects overtime past the 35 hour legal threshold and applies the correct surcharge

  4. Shows results in both HH:MM and decimal format at the same time

  5. Handles night shifts that cross midnight without breaking

  6. Exports timesheets to CSV or PDF

Everything runs in the browser. No signup, no account, no data sent to any server. I wanted something private enough that I would trust it with my own hours, so that is the bar I built it to.

It is free to use, and I built it mainly for employees checking their payslip, freelancers logging billable hours, and small business owners handling payroll without a finance team.

If you deal with French labor law in any capacity, I would genuinely like your feedback. I am still adding features based on real use cases, not guesses.

1 Comment

  1. 1

    This is a great example of where “simple calculators” stop being simple. Once local labor rules, thresholds, and edge cases enter the equation, correctness becomes the product—not UI or features. If the calculations are truly reliable, that alone is the moat here.

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Tired of decimal vs HH:MM payroll mix-ups, I built a free calculator that gets French labor law overtime and hours right, breaks, night shifts, split days included.