How to Manage Zero-Hours Contract Workers with Timesheet Software

Zero-hours contracts are everywhere now — hospitality, retail, care, gig work. If you manage zero hours contract workers, you've discovered the same paradox every small business finds: they offer brilliant flexibility, but they create a complete headache for timesheets, payroll, and compliance that fixed-hour workers simply do not.

As defined by gov.uk, zero-hours contracts mean no minimum hours guaranteed and no obligation for workers to accept shifts. Workers work when it suits both of you. But someone still has to track every hour, calculate holiday accrual correctly, verify minimum wage requirements, and make sure you're not accidentally breaching working time regulations. That someone is usually you, on a Friday night, in a spreadsheet.

This guide covers how to manage zero-hours workers with timesheet software, with a focus on what actually matters: payroll accuracy, legal compliance, and treating workers fairly.

The anatomy of a zero-hours contract

You can't manage what you don't understand, so let's be clear about what makes zero-hours different.

No guaranteed hours. That's the definition. The employer doesn't promise any minimum, and the worker doesn't have to accept what's offered. Week-to-week, you might call in two people or twelve, and they might say yes or no. It's genuinely flexible — which is why hospitality and care homes rely on it, and which is why some industries have built entire business models around zero-hours scheduling.

Pay varies wildly. A permanent employee earning £2,000 a month is predictable. A zero-hours worker might earn £150 one week and £800 the next. That variability is fine, but it means you can't run payroll on autopilot. Every single shift has to be recorded accurately because there's no fixed salary to fall back on.

They still have rights. This catches a lot of small businesses by surprise. Zero-hours workers get:

Holiday pay (accrued at 12.07% of hours worked, or rolled into the hourly rate — you choose)
Statutory sick pay if they meet the eligibility rules
Minimum wage protection (checked every pay period, not assumed)
Working time limits (max 48 hours per week averaged, rest periods, etc.)
Unfair dismissal protection after 2 years

That's not "flexibility lite" — that's the same baseline as everyone else, just calculated differently. Your timesheet system has to be able to handle this, which is why choosing the right timesheet software from the start matters.

Available doesn't mean working. A worker might be on your books and available for shifts but not offered any in a given week. Their timesheet shows zero hours. That's fine — but your system needs to distinguish between "not offered" and "worked zero." The difference matters for compliance, for understanding who's genuinely engaged, and for staying accurate when tracking time.

Why you can't wing it: the payroll math

If you run a tight ship, you're probably thinking: "How hard can it be? Clock in, clock out, calculate pay, done."

Here's the thing: that works for one or two casual workers. Once you're managing more than a handful of zero-hours staff, manual tracking breaks down. You'll miss shifts, double-count hours, mess up holiday accrual, and end up underpaying someone — then you're dealing with a wage claim and an HMRC enquiry.

Timesheet software handles this automatically. It records hours, calculates accrual in real time, feeds payroll with clean data, and gives you audit-ready records. For zero-hours workers, it's not a nice-to-have. It's the difference between running smoothly and firefighting every pay run.

Holiday pay is the complicated bit. If a worker has earned £1,200 over 12 weeks and you owe them 5.6 weeks of statutory leave, the calculation depends on your approach:

Roll-up method: Pay a higher hourly rate that includes the holiday element (e.g., 10% extra). Simple, transparent, no accrual calculation needed.
Accrual method: Pay 12.07% of earnings into a holiday pot, then pay it when they take leave.

Both are legal. Either way, your timesheet records have to be accurate to the penny, and your payroll integration needs to handle whichever method you choose.

Minimum wage checks. National Minimum Wage requirements don't disappear just because hours are variable. If you contracted a zero-hours worker at, say, £8/hour and they worked only 5 hours one week, they earned £40 — above minimum wage. But if a calculation error shows 4 hours and 50 minutes, they fall short. That's a compliance fail. You need to verify the minimum wage calculation every pay period, not assume it's fine.

Setting up timesheet tracking that works

Use the same system for everyone

Don't create a shadow process for zero-hours workers. Use your standard timesheet platform for them, just as you would for permanent staff. It keeps the data clean, reduces admin, and removes the temptation to cut corners with a spreadsheet.

Relentify's timesheet system handles variable-hour workers naturally — same clock-in process, same approval workflow, same reporting. A worker can clock in for a two-hour shift and a twelve-hour shift the same way. Your payroll doesn't care; it just processes whatever hours land in the system.

Record every shift, no matter how short

A two-hour shift is just as important as an eight-hour shift. The system should make it equally easy to record both. If your software treats short shifts as edge cases, you'll find people rounding them away ("close enough to 2.5 hours, let's just call it 3") and suddenly your records are fiction.

Track offered and declined shifts (optional but useful)

You're not obliged to record the shifts you offered that were declined. But if you do, it gives you evidence if a worker claims they were constructively dismissed by not being offered hours. It also helps you understand who's reliably available and who's drifting away.

Accommodate irregular schedules

Zero-hours workers don't appear on a fixed rota. Some weeks they work 30 hours. Some weeks, zero. Your scheduling system should handle this without treating zero-hour weeks as errors. And your payroll should process correctly even when a worker has no hours in a period (which means no pay, no national insurance, nothing owed for that week).

Common scenarios: how to handle them

Irregular patterns. A worker does twenty hours one week, nothing the next, twelve hours the week after. That's normal. Your timesheet system should show the reality without question or comment. And your payroll export should generate a clean file showing the actual hours, week by week.

Multiple employers. Some zero-hours workers work for you and two other businesses. You can only track hours worked for you (you can't see their other jobs). But if a worker mentions they're also working elsewhere, or if you notice they're regularly exhausted, a quiet conversation about safe working hours is appropriate. Working time regulations max out at 48 hours per week averaged — across all employers. You can't control their other job, but you're not obliged to ignore it.

Transitioning to permanent. If a zero-hours worker's pattern becomes regular (say, consistently 25 hours per week for six months), they may have a claim that a permanent contract is implied. More practically, if you want to hire them permanently, your historical timesheet data shows their actual hours and helps set a fair permanent contract. That's useful.

Ending the arrangement. When you stop offering shifts, the worker is entitled to any accrued but untaken holiday pay. Calculate this from your timesheet records. If you don't have complete records, the calculation becomes a negotiation — and usually an expensive one. Complete records prevent that.

The legal bits (yes, they matter)

Exclusivity is out. UK employment law makes it illegal to prevent a zero-hours worker from taking other work. If your contract has an exclusivity clause, remove it. Acas guidance confirms this. Attempting to enforce it opens you to a claim.

Regular patterns establish a contract. If timesheet records show that a worker has been working the same hours week after week for months, a tribunal might find that a regular contract is implied — regardless of what the written agreement says. This isn't a problem if you're treating them fairly. It becomes a problem if you're using zero-hours to dodge the rights that come with permanence.

Tax and national insurance. Variable earnings mean variable payroll deductions. Your timesheet data feeds directly into tax calculations — get the hours wrong and you'll be doing amendments later. Software that integrates with payroll handles this automatically; spreadsheets do not.

Frequently Asked Questions

Q: What's the difference between a zero-hours contract and a part-time contract? A: A part-time contract guarantees a minimum number of hours (e.g., 16 hours per week) and the employer must offer them. A zero-hours contract guarantees nothing — the employer doesn't promise any hours, and the worker doesn't have to accept what's offered. The worker's rights are the same; the flexibility is different. You'll manage both with the same timesheet system.

Q: Do zero-hours workers get holiday pay? A: Yes. The statutory entitlement is 5.6 weeks per year (28 days for a full-time worker). For zero-hours workers, this is calculated as 12.07% of hours worked (or sometimes rolled into the hourly rate). They accrue it as they work, and you must pay it when they take leave or when the contract ends. Underpaying holiday is one of the most common mistakes — which is exactly why software is essential.

Q: Can I use a spreadsheet to track zero-hours workers? A: Technically, yes. Practically, no — not if you have more than a handful. A spreadsheet doesn't catch missing shifts, doesn't calculate accrual automatically, and doesn't integrate with payroll. Mistakes happen. Timesheet software removes the risk and gives you an audit trail. Once you're managing more than two or three zero-hours workers, the admin debt becomes real.

Q: What happens if I don't offer a zero-hours worker any shifts for months? A: If the arrangement ends, you owe any accrued holiday pay. If you've just stopped offering shifts but haven't formally ended the contract, there's ambiguity — they might claim constructive dismissal. The cleanest approach: if you're not going to offer work, formally end the contract and pay out what's owed. Records show you did the right thing.

Q: Do zero-hours workers have to accept every shift I offer? A: No. That's the whole point of the contract. They can say no. If you make it uncomfortable for them to decline (punishing refusals with fewer offers, for instance), you're inching toward an unfair dismissal or discrimination claim. It's not worth it.

Q: How do I calculate minimum wage for zero-hours workers? A: Check it every pay period. Divide total pay by total hours worked. If the result is below the statutory minimum for their age group, top them up. It's rare, but it happens — usually due to calculation errors or piece-rate work that doesn't add up.

Q: Can I change the contract terms whenever I want? A: No. Zero-hours doesn't mean "no obligation to the worker." Once you've sent the written contract, changing key terms (pay rate, exclusivity, notice period, etc.) requires agreement. Unilateral changes invite claims. And if the worker has been working regular hours under zero-hours terms, a tribunal might find the contract has become permanent anyway.

Q: What records do I need to keep? A: Timesheets (every shift, dates, hours, pay), any shifts offered and declined (helpful but optional), holiday taken and accrued, payroll records, and any communication about the arrangement. Keep them for at least six years (or the statutory minimum for your jurisdiction). They're your defence against wage claims and your evidence of fair treatment.

Best practices: how to do this well

Treat zero-hours workers as properly employed. The fact that hours aren't guaranteed doesn't mean they're second-class staff. Give them the same access to the timesheet system, the same notice of shifts, and the same respect as permanent employees. If you're consistently scheduling someone for 30 hours per week, a fixed contract would be fairer to them (and simpler for you).

Communicate clearly. At the outset, explain:

How shifts are offered (text, app, email?)
When they need to confirm acceptance
How timesheets are submitted and approved
How pay is calculated and when it's paid
How holiday works and when they can take it

Clear communication prevents most disputes. It also builds trust, which makes retention easier (and zero-hours workers are notoriously hard to retain if they feel undervalued).

Monitor your patterns. If a "zero-hours" worker is reliably working 20+ hours per week, consider whether you should convert them to a permanent contract. It might simplify your admin and give them (and you) more security.

Keep complete records. This is non-negotiable. Timesheet software does it automatically. A spreadsheet is asking for trouble. Complete, accurate records are your defence against claims, your proof of compliance, and your evidence that you've treated the worker fairly.

Zero-hours contracts solve a real problem — they let you flex staffing to match demand. But that flexibility comes with a price: you have to track everything, calculate entitlements correctly, and stay compliant with employment law.

Trying to manage this with a spreadsheet doesn't scale. Timesheet software isn't optional once you're managing more than a couple of zero-hours workers — it's the foundation of fair pay and legal compliance.

If you're looking to consolidate your current toolstack, explore how timesheet software can simplify management for teams mixing permanent and casual workers. Or start with our guide to choosing timesheet software.

Try Relentify free for 14 days to see how it handles your zero-hours workers.