Excel for Staff Scheduling: Why It Stops Working at 20+ Staff

There’s a spreadsheet on someone’s desktop right now with staff names down the left side, days of the week across the top, and a colour-coding system that only the person who built it understands. It’s the roster. It takes 2-3 hours to build each week. It breaks every time someone calls in sick. And if the person who makes it goes on leave, nobody else can produce it.

This is how most small businesses start with staff scheduling, and for a handful of employees, it works fine. This article is about where it stops working — and the specific problems that surface when you try to scale a spreadsheet roster past about 20 staff.

Where Excel Rostering Works

Excel handles scheduling well when:

• You have fewer than 15 staff — the whole roster fits on one screen
• Shifts are simple and consistent — everyone works the same pattern, or close to it
• One person builds the roster — they know every employee’s availability in their head
• Award rules are straightforward — flat hourly rates, no complex penalty rates or overtime tiers
• Shift swaps are rare — the roster goes out and mostly sticks

If that’s your business, keep going. A clean spreadsheet with conditional formatting for overtime hours and a few data validation dropdowns is a perfectly reasonable rostering tool. Don’t fix what isn’t broken.

Breaking Point 1: Availability and Preferences Become Unmanageable

When you’ve got 8 staff, you know who can’t work Tuesdays and who needs every second Friday off. You keep it in your head. At 25 staff, you can’t. People have university schedules, second jobs, custody arrangements, medical appointments, and preferences that change month to month.

In Excel, availability is typically tracked in a separate tab — or worse, in a folder of text messages and emails that the roster builder has to cross-reference manually. Every week, they’re mentally juggling constraints while dragging names into cells, hoping they haven’t forgotten that Jake can’t work before 10am this semester.

The result is either a roster that ignores availability (leading to no-shows and resentment) or a roster that takes hours to build because the constraint-checking is entirely manual.

Breaking Point 2: Award Compliance and Overtime

This is where the real risk lives, especially in Australia.

Modern Awards are complicated. Penalty rates for evenings, weekends, and public holidays. Minimum engagement periods. Maximum ordinary hours per day and per week. Overtime thresholds that differ between full-time, part-time, and casual staff. Break requirements between shifts.

In Excel, you can build formulas to calculate some of this. But the formulas get complex fast, and they need to account for every edge case in your applicable Award. A casual working a Sunday shift that crosses midnight into a public holiday Monday — what’s the rate? An employee who’s already done 38 ordinary hours this week getting rostered for Saturday — is that all overtime, or do the first two hours count differently?

Most businesses handle this by eyeballing it and fixing mistakes in payroll later. That’s a compliance risk. The Fair Work Ombudsman recovered over $532 million in unpaid wages in the 2022-23 financial year, and incorrect roster-based calculations are a major contributor.

Breaking Point 3: Shift Swaps and Last-Minute Changes

The roster goes out on Thursday. By Saturday morning, two people have swapped shifts via text, someone’s called in sick, and a casual has picked up an extra shift. The spreadsheet still shows the original plan. Nobody updated it because nobody has access to it on their phone at 6am.

Now the roster is fiction. The manager doesn’t know who’s actually working today without calling the site. Payroll will be processed against the spreadsheet, not reality, so someone will be paid for a shift they didn’t work and someone else won’t be paid for one they did.

Excel has no mechanism for self-service changes. Staff can’t log in, see their shifts, request swaps, or update their availability. Every change flows through one person — the roster builder — who becomes a bottleneck and a single point of failure.

Breaking Point 4: No Visibility Across Locations or Departments

The moment you have staff who work across multiple sites — or departments within a large site — a single spreadsheet roster falls apart. You need to see who’s available across all locations, avoid double-booking someone at two sites, and balance coverage so no location is understaffed while another has people standing around.

Most businesses handle this with separate roster spreadsheets per location, which means no cross-location visibility without manually opening and comparing multiple files. That’s how you end up with three baristas rostered at one cafe and one at another on the same Saturday morning.

Making the Most of Excel While You’re Still Using It

If you’re not ready to move on, tighten up what you’ve got:

• Centralise availability — create a structured table where staff enter their availability for the coming month. Use data validation to restrict entries to “Available,” “Unavailable,” or “Preferred.” Don’t rely on texts and emails.
• Build an overtime tracker — use SUMIFS to total hours per person per week, and conditional formatting to highlight anyone over 38 ordinary hours. It won’t catch every Award nuance, but it’ll catch the obvious ones.
• Version your rosters — save each published roster as a dated copy. When payroll queries come up, you need to know what the roster said on the day, not what it says now after six mid-week changes.
• Create a change log tab — when shifts are swapped or added, log the change with a date and reason. This gives you a basic audit trail and stops the “he said, she said” disputes about who was supposed to work when.

Excel rostering works until your team outgrows one person’s memory. The signs are consistent: the roster takes longer each week, mistakes slip through more often, compliance feels like guesswork, and every sick call triggers a scramble. When the workaround becomes the workload, it’s time for something purpose-built.