Timesheet sign-off: digital, verifiable and on time

Timesheet sign-off means the client confirms with a signature that the hours on the timesheet are right: who worked, on which days, for how long and on which project. That signature underpins your invoice and the technician's pay, and it is the first piece of evidence if a dispute arises later. Digital sign-off only works well if the signature is tied to exactly the hours that were signed and you can show who did what, and when.

Who timesheet sign-off matters to

Sign-off matters wherever people put in hours at someone else's site: secondment, installation, field service and on-site maintenance. Think of a seconded electrician at a process plant, an installation crew spending a week on a sorting line in a distribution centre, or contractors during a shutdown at a waste-to-energy plant. In each case the invoice depends on hours the client did not count themselves.

Both sides have something at stake:

• The supplier wants to invoice without argument and pay the right wages. A signed timesheet shows that the client has seen the hours and agreed to them.
• The client only wants to pay for work actually done. If you outsource maintenance, client approval of the timesheet is your check before the invoice, just as goods receipt in purchasing is for parts.

Disputes rarely concern the whole week; they are about details. Was the break deducted? Does the first morning's travel count? Was the Saturday work agreed? The sooner the client signs, the smaller those disputes stay.

What a good timesheet contains

A timesheet is only ready to sign if someone who wasn't there can see what happened. It should include:

If a technician works for two clients in one week, each client signs only for the hours on their own project. Blank days or "to follow" have no place on a timesheet presented for signature.

Timesheet sign-off in five steps: from filling in to processing

The diagram below shows the five steps, and what happens when the manager sends a timesheet back.

1. 1Employee fills in. Daily, with times, break, project and hour type. If the times come from clock records, the employee copies them across and only adds what is missing. How to set up that recording is covered in time tracking for technicians.
2. 2Client signs. Per project, preferably at the end of the week or when a short job is finished, with name, date and time. The client sees only the hours on their own project.
3. 3Submit. The employee submits the week. From then on there is a locked version that cannot change unnoticed.
4. 4Manager reviews. The manager approves the timesheet or sends it back with a reason, such as a missing signature or a 13-hour shift without explanation. Nobody approves their own hours.
5. 5Process. The approved timesheet goes as a PDF to payroll, invoicing and the archive.

A timesheet that is sent back returns to the employee. If the hours change in the process, the client signs again.

What the manager checks

Approving is more than ticking a box. Five checks catch most errors:

• Complete. Every working day filled in, and a signature for each project.
• Plausible. The hours fit the schedule, the job sheets and the client agreements.
• Within working time rules. Shifts over 12 hours or short rest periods are a signal to look into.
• Right hour type. Overtime only where it really was overtime; on-call hours with the callout attached.
• Travel costs. Mileage that fits the route between branch or home and the site.

If something is wrong, send the timesheet back with a specific reason, so the employee knows what to fix.

Signing digitally: what the law says

Sign-off is first and foremost an agreement between you and your client; together you decide what kind of signature to use. It still helps to know the legal framework. What follows is an overview, not legal advice.

The EU eIDAS Regulation distinguishes three types of electronic signature:

Under eIDAS, an electronic signature may not be denied legal effect solely because it is electronic or not qualified. A qualified signature has the equivalent legal effect of a handwritten one; for the other two, the regulation leaves the legal effect to national law. In the Netherlands, Article 3:15a of the Dutch Civil Code gives simple and advanced electronic signatures the same legal effect as a handwritten signature, provided the method used is sufficiently reliable given the purpose and all the circumstances.

For a timesheet, a simple electronic signature is the obvious choice: a qualified signature requires a qualified certificate and device for every signatory, which is heavy going for a weekly timesheet. Whether your method is reliable enough depends on what you record around it; more on that below. Where large sums are involved or you expect disputes, agree in the contract that the digitally signed timesheet is the basis for invoicing.

What makes a digital signature reliable

A scribble on a screen proves little on its own. Its value lies in what you record around it:

• Tied to exactly the signed content. A good system calculates a checksum (hash) of the hours at the moment of signing and stores it with the signature. If a single minute changes later, the checksum no longer matches and the signature lapses. Whatever changes is signed again.
• Name and role of the signatory. A signature without a legible name says little. Record in what capacity someone signed, too.
• Date and time. Signed on Friday at 16:05 is not the same as signed three weeks later.
• A locked version on submission. What has been submitted is fixed. Corrections create a new version, not a silent edit.
• A trail of who did what. Filling in, signing, submitting, sending back, approving: every step with a name and a time.

That link to the content matches one of the requirements eIDAS sets for an advanced signature: any later change to the data must be detectable. On its own it does not make a signature advanced; for that, it must also be uniquely linked to and capable of identifying the signatory, and created using signature creation data under the signatory's sole control.

From paper timesheets to digital sign-off

Many companies still have a paper timesheet signed: the technician fills it in, the client signs at the bottom and on Friday a photo or a pile of paper goes to the office. It works, but it means retyping, slips go missing and afterwards nobody can tell whether anything was added after signing.

With a digital timesheet, the client signs on a screen, for example on the technician's phone, and nobody has to retype the hours: once submitted, they are ready for approval straight away. To make the switch:

• Start with one client who signs regularly and is open to a trial.
• Explain to the client's contacts in advance what they will see and what their signature means.
• Agree what happens if there is no signal on site to sign.
• Don't run paper and digital side by side for long: two routes mean double work and doubt about which version counts.

Agreeing the rules with each client in advance

Many timesheet disputes are really disputes about agreements that were never made. Agree with each client in advance on:

• Breaks. Is half an hour deducted as standard, or the actual break?
• Travel time and mileage. From the branch or from home, at what rate per kilometre and from what distance?
• Premiums per hour type. The percentage for overtime, evenings, weekends and on-call. How to use those percentages to work out payable hours is covered in recording overtime.
• Who may sign. Names or roles, and who signs when they are away.
• When signing happens. Per week, per job or, during a shutdown, daily.
• Rounding. To the quarter hour or to the minute, and the same for start and finish?

Put these agreements into the system where timesheets are made, so they are applied to every timesheet automatically rather than relying on someone's memory. How client agreements carry through into the weekly timesheet is shown on the time tracking page.

How long to keep a signed timesheet

An approved timesheet is part of your records. In the Netherlands, three rules determine how long you keep it:

• Tax: seven years. Businesses must keep their accounting records, including supporting documents, for seven years (Article 52 of the General State Taxes Act, in Dutch). Timesheets that support pay and invoices are part of that. You may keep paper timesheets digitally, provided the transfer is accurate and complete and the data stays readable for the whole retention period.
• Working time: at least 52 weeks. If the timesheet also serves as your record under the Working Hours Act, keep it for at least 52 weeks.
• Privacy: no longer than necessary. Under the GDPR, personal data may not be kept longer than necessary for its purpose. While a statutory retention period runs, such as the tax one, keeping the timesheet is necessary; after that, delete it, including the name and signature of the person who signed at the client.

Keep the approved version as a PDF, with the signature and trail, and give clients access only to the hours on their own projects.

Common pitfalls in timesheet sign-off

• Signing a month later. Nobody remembers whether Tuesday was 8 or 9 hours; the client signs blind or not at all.
• Signing an incomplete timesheet. Blank days or "to follow" make the signature worthless for whatever is added later.
• Editing after signing. Adding an hour after the signature means invoicing something that was never approved.
• Paper slips. Lost, illegible, rain-soaked, or a photo in a group chat that nobody can find.
• Unclear who signs. The security guard at the gate or one of the client's technicians signs, and in a dispute turns out not to have the authority.
• Approving without looking. Approving several timesheets at once is handy for those without exceptions; look at the exceptions first.
• Managers approving their own hours. Then the second pair of eyes is missing.