Compressed Hours Calculator: Work Out Your New Schedule

A compressed hours calculator works out your new working pattern when you fit the same weekly hours into fewer days. You enter your current weekly hours, your standard working day length, and the number of days you want to work, and it returns your new daily hours and the extra time off you gain each week. This is the core calculation behind every compressed hours arrangement, whether you’re moving to a 4-day week or a 9-day fortnight.

Formula

The basic compressed hours formula is simple: divide your total contracted weekly hours by the number of days you plan to work.

New daily hours = Weekly hours ÷ Number of working days

Where:

• Weekly hours – your contracted hours over a full week (e.g., 37.5 hours)
• Number of working days – the days you will actually attend work (e.g., 4)

The result is the length of each working day, usually expressed in hours and minutes. For example, 37.5 ÷ 4 = 9.375 hours, which is 9 hours and 22.5 minutes (0.375 × 60 = 22.5).

Worked Example

Take the default values: you work 37.5 hours a week over 5 days, and you want to compress into 4 days.

1. Start with your weekly hours: 37.5
2. Divide by the new number of days: 37.5 ÷ 4 = 9.375
3. Convert the decimal to minutes: 0.375 × 60 = 22.5 minutes
4. So your new daily hours are 9 hours and 22.5 minutes, or about 9h 23m.

The calculator shows 9.38 hours (rounded to two decimals). That matches the formula exactly.

Why Compress Hours? The Background

Compressed hours are a form of flexible working where an employee works their full contractual hours but over fewer days. The most common pattern is a 4-day week (e.g., 37.5 hours across Monday to Thursday), but other arrangements exist: a 9-day fortnight (80 hours over 9 days instead of 10), a 3.5-day week, or even a 4.5-day week with one shorter day.

The idea gained popularity as a work-life balance tool. Employers often offer it as a retention strategy, and some countries have run trials of a 4-day week with no loss of pay – though those trials usually reduce total hours, not just compress them. Compressed hours specifically keep the same total hours, so pay stays the same, but each working day is longer.

It’s important to distinguish compressed hours from reduced hours (part-time work) – in compressed hours, your total weekly hours remain unchanged, so your salary and holiday entitlement are typically unchanged too.

How to Choose Your Compressed Pattern

Choosing the right pattern depends on your role, your energy levels, and your employer’s policy. Here are the main options:

• 4-day week – The most popular. You work ~9–10 hours a day and get one full day off. Common in office roles.
• 9-day fortnight – You work 9 days in two weeks and get one extra day off every other week. Daily hours increase by about 0.5–1 hour.
• 4.5-day week – You work a half-day on the fifth day. Daily hours increase less, but you only get a half-day off.
• 3-day week (intensive) – Only possible if your weekly hours are low or you can work very long days (e.g., 12-hour shifts). Common in healthcare or emergency services.

When deciding, consider your commute time – longer days might still save total commute time if you travel fewer days. Also consider your job’s demands: if your role requires daily client contact, a 4-day week may not be feasible unless you have coverage.

Common Mistakes and Misconceptions

One frequent mistake is confusing compressed hours with flexitime. Flexitime lets you vary your start and end times within a day, but you still work the same number of days. Compressed hours change the number of days, not just the times.

Another error is miscalculating the daily hours when the weekly total isn’t a round number. For example, 35 hours over 4 days is 8.75 hours, which is 8 hours 45 minutes. Many people round to 8.5 or 9, which over a year adds up to significant under- or over-time.

Also, be careful with lunch breaks. If your contract says 37.5 hours excluding unpaid breaks, then a 4-day week means you’re at work for 9.5 hours (9h 23m + 30–60 min lunch). If the contract includes paid breaks, the calculation is different. Always check your contract’s definition of working hours.

Finally, don’t forget that holiday entitlement is usually calculated in days, not hours. If you compress to 4 days, a week of holiday still uses 5 days of leave, but you only would have worked 4 of them – so you may end up with more actual days off than before. Some employers convert holiday to hours to avoid this confusion.

Limits of the Calculator

This calculator only handles the arithmetic of hours and days. It doesn’t account for:

• Breaks (unpaid or paid) – you must add these manually.
• Overtime – if you regularly work extra hours, your compressed days will be even longer.
• Shift patterns – if you work shifts, your weekly hours may vary, so use an average.
• Legal limits – many jurisdictions cap daily working hours (e.g., 8 hours in some EU countries, 10 in others). Check your local labour law before agreeing to a 12-hour day.
• Employer policy – not all employers allow compressed hours, and some require a trial period.

The formula also assumes you work the same number of hours every day. If you want a different pattern (e.g., 4 longer days and 1 shorter day), you need to adjust the calculation manually.

How to Propose Compressed Hours to Your Employer

If you’re considering compressed hours, here’s a practical approach:

1. Check your employee handbook or contract for a flexible working policy.
2. Calculate your proposed daily hours using this calculator – have the numbers ready.
3. Identify how you’ll cover your responsibilities on your day off (e.g., a colleague covers urgent matters).
4. Suggest a trial period (e.g., 3 months) to review how it works.
5. Be prepared to compromise – maybe a 9-day fortnight instead of a 4-day week.

Employers often worry about coverage and communication. Address those concerns directly in your proposal.

Frequently Asked Questions

How many hours a day is a compressed 4-day week?

It depends on your weekly hours. For a standard 37.5-hour week, a 4-day week means 9.375 hours per day, which is 9 hours and 22.5 minutes. For a 40-hour week, it’s 10 hours per day.

Do I get paid the same with compressed hours?

Yes, if you keep the same total weekly hours, your salary stays the same. Compressed hours are not a pay cut – you’re just working the same hours in fewer, longer days.

What is a 9-day fortnight?

A 9-day fortnight means you work 80 hours over 9 days instead of 10, giving you one extra day off every two weeks. Your daily hours increase from 8 to about 8.89 hours (8h 53m) for a 40-hour week.

Can I compress hours if I work part-time?

Yes, part-time workers can also compress. For example, a 20-hour week over 3 days could become 2 days of 10 hours. The same formula applies: divide your weekly hours by the number of days you want to work.

What happens to my holiday entitlement with compressed hours?

Your holiday entitlement is usually based on your contractual days, not hours. If you work 4 days a week, you’ll still get the same number of days off, but each day of leave covers a longer working day. Some employers convert holiday to hours to make it fair – check your policy.

Is there a legal maximum for daily working hours?

In many countries, yes. For example, the EU Working Time Directive limits the average working week to 48 hours and requires rest periods. Some countries have specific daily limits (e.g., 8 or 10 hours). Always check your local labour laws before agreeing to a compressed schedule.

Related

• Clock Calculator Time Duration: How to Find It
• Clock Duration Calculator: How to Find Time Spans
• Clock Time Calculator: Minutes & Seconds

in t | Current weekly hours | hours | 37.5 | 0
in d | Standard working days per week | days | 5 | 1
in n | Days you want to work | days | 4 | 1
out new_day | New daily hours | hours | t / n | 2
out saved | Time off gained per week | hours | t - (t / n) * n | 2