There's a smarter way to handle this, and it starts with admitting that traditional spreadsheets weren't built for this kind of time-based logic. The user asking for help with long service leave calculations in NSW is facing a problem that thousands of payroll and HR professionals hit every week: splitting a date range into pieces that fall inside or outside a rolling window. Doing that manually is not just tedious, it's error-prone, and in a compliance context, errors cost money.
The question itself is straightforward. An employee took a 20-day unpaid break last March. Five of those days fall within the last 12 months, and 15 are outside it. The user needs a formula that can identify, for each break, exactly how many days belong to each relevant period, here, the previous five years and the previous 12 months. This is not a lookup problem. It's a date-intersection problem, and most spreadsheet users don't realize they can solve it with a single array formula or a helper column using `MAX` and `MIN` to calculate the overlap between two date ranges.
What this really reveals is a gap in how we think about spreadsheets. Most people treat cells as static containers for numbers and text. But when you start working with time-based rules, rolling windows, service periods, exclusion intervals, you need the sheet to think in ranges, not just points. The formula that solves this user's problem is simple in concept: for each break, the number of days overlapping with the last 12 months equals `MAX(0, MIN(end_of_break, today) - MAX(start_of_break, today - 365) + 1)`. Extend that pattern for five years, and you have a reusable template for any jurisdiction's leave rules.
The practical takeaway is that this approach scales. Once you build one rolling-window calculator, you can adapt it for annual leave caps, parental leave eligibility, or any other rule that depends on time boundaries. The user's question about a single 20-day break is just the starting point. The real value comes when you apply the same logic to a sheet with hundreds of employees and dozens of breaks each. That's when a manual process becomes unmanageable, and a formula-driven method becomes indispensable.
Don't settle for a spreadsheet that forces you to count days on a calendar. The tools already exist to make the sheet do the counting for you, and the only barrier is knowing which functions to combine. Start with `MAX` and `MIN` for range overlap, add `TODAY()` for dynamic rolling windows, and wrap it in a conditional check so you only calculate for breaks that actually intersect the period. That's the formula stack that turns a frustrating manual task into a repeatable, audit-ready calculation.