You've just hired someone with a 90-day probation period. But when exactly does it end? The answer depends on whether your company counts in calendar days or business days — and the difference is significant.
Calendar Days vs Business Days: The Impact
For an employee starting on January 5, 2026:
- 90 calendar days = April 5, 2026 (about 3 months)
- 90 business days = May 15, 2026 (about 4.5 months)
That's a 6-week difference. Getting this wrong can create legal issues around benefits eligibility, termination rights, and performance review timing.
Calculate your probation end date
Use our "Add Days to Date" calculator — enter the start date and number of days to get the exact end date.
Open Probation Calculator →Which Standard Do Most Companies Use?
The majority of employers use calendar days for probation periods. This is the most common approach in:
- The United States (most states)
- United Kingdom
- Australia
- Canada
However, some organizations — particularly government agencies and unionized workplaces — specify business days. Always check your employment contract or company handbook.
Common Probation Period Lengths
- 30 days — Common for hourly/temporary positions
- 60 days — Used by some mid-size companies
- 90 days — The most common standard in the US, UK, and Australia
- 6 months — Common in Europe, especially for senior roles
What Happens During Probation?
During a probation period, employers typically have more flexibility to terminate employment. After probation ends:
- Full employment protections kick in
- Benefits like health insurance may become active
- Notice period requirements may change
- Performance reviews become part of the formal record
Tips for HR Professionals
- Document the exact counting method in your offer letter — "90 calendar days" or "90 business days"
- Set calendar reminders for the 60-day and 80-day marks to begin the review process
- Account for holidays — a probation period over December will have fewer working days for evaluation
- Use a calculator — don't count manually. Calculate the exact end date here.
How Probation Periods Are Used Around the World
Probation period lengths vary significantly by country and industry. In the United States, most states follow "at-will" employment, so formal probation periods are more of a company policy than a legal requirement — 90 days is the most common length, though some companies use 30, 60, or 180 days. In the United Kingdom, probation periods commonly run 3 to 6 months, and employees generally need 2 years of continuous service before gaining full unfair dismissal protection, making the probation period less legally significant than in some other countries.
In many European countries, probation periods are more tightly regulated. Germany typically limits standard probation periods to 6 months, during which notice periods are shortened (often to 2 weeks) compared to standard employment. France allows probation periods to be renewed once, but total length is capped by law depending on the employee's role and seniority.
What Happens During a Probation Period
During probation, both employer and employee typically have more flexibility to end the employment relationship, often with shorter notice requirements than standard employment. This is the period when performance expectations, cultural fit, and job suitability are assessed most closely. Many employers schedule formal check-ins at the 30, 60, and 90-day marks to review progress against expectations set at hiring.
Calculating Your Probation End Date Correctly
The most common mistake when calculating a 90-day probation period is confusing calendar days with business days. If your contract specifies "90 days" without qualification, it typically means 90 calendar days — which is approximately 3 months, not 90 working days (which would be closer to 18 weeks or 4.5 months). Always check your specific employment contract, as some companies define probation in "business days" explicitly, which extends the actual calendar duration significantly.
Frequently Asked Questions
Is a 90-day probation period 90 calendar days or 90 business days?
Unless your contract specifies otherwise, "90 days" almost always means 90 calendar days — roughly 3 months. If your contract specifies "90 business days," that would extend to approximately 4.5 months of calendar time.
Can an employer extend a probation period?
In many jurisdictions, yes — provided it's outlined in the employment contract or company policy and communicated to the employee before the original probation period ends. Some countries limit how many times or how long a probation period can be extended.
What rights do employees have during probation?
Rights during probation vary by country. In most jurisdictions, basic protections against discrimination still apply, but protections against unfair dismissal are often reduced or unavailable until probation is completed. Always check local employment law for specifics.
Does probation affect notice periods?
Often yes. Many employment contracts specify shorter notice periods during probation (for example, 1 week) compared to standard employment (which might be 4 weeks or more), applying to both employer and employee.
How do I calculate my exact probation end date?
Enter your start date in our Date Difference Calculator or Add Days to a Date tool, and add the number of days specified in your contract to get the exact end date.