Fit Notes and Self-Certification: When Do You Actually Need One for Sick Pay in 2026/27?

Quick answer

For most short illnesses, self-certification is all that's needed — an employee simply tells their employer they're unwell, following the employer's normal process, for up to seven calendar days. A fit note only becomes necessary once sickness absence runs into an eighth day or beyond, and it's a common source of confusion how this interacts with when Statutory Sick Pay actually starts being paid.

Self-certification: the first seven days

For the first seven calendar days of any period of sickness (including non-working days within that period), an employee can self-certify without providing any medical evidence at all — simply reporting the absence following the employer's standard notification process (usually a phone call or message by a set time on the first day). This applies regardless of whether the employer has its own separate sickness reporting form, since the statutory position doesn't require evidence in this window.

When a fit note kicks in

From the eighth calendar day of sickness onwards, a fit note is generally needed — obtained from a GP or, for some conditions, another registered healthcare professional such as a nurse, occupational therapist, pharmacist or physiotherapist with fit note certification training. This isn't simply a bureaucratic formality: it also determines continued eligibility for Statutory Sick Pay, since an employer can reasonably require evidence to keep paying SSP for longer absences.

Employers asking for evidence sooner than day eight

Some employers set their own company sickness absence policy requiring a fit note (or some other form of medical evidence) earlier than the statutory eighth-day point — this is allowed, since it's an internal company policy rather than a statutory requirement. However, requiring an employee to personally cover an unreasonable cost purely to satisfy an earlier internal policy request is a common point of dispute, since GPs can charge a fee for fit notes requested outside the standard, medically necessary process — this is worth checking against the specific company policy and, where relevant, raising with HR.

What a fit note actually communicates

A fit note isn't simply a binary "off sick" stamp — it records a healthcare professional's assessment of whether someone is "not fit for work" or "may be fit for work", the latter often accompanied by suggested adjustments such as reduced hours, altered duties, or a phased return to work. This gives an employer more useful information to plan around than a blanket absence, and can support a smoother, earlier return to work where appropriate rather than an all-or-nothing approach.

SSP doesn't pay from day one

It's a frequent point of confusion that Statutory Sick Pay isn't payable for the first three "qualifying days" of a period of sickness — these are unpaid waiting days, with SSP only becoming payable from the fourth qualifying day. If someone has had a linked period of sickness (broadly, within eight weeks of a previous SSP-paid period), the waiting days may not need to be served again, which is a detail worth checking for anyone with recurring health conditions.

Bottom line

Know the seven-day self-certification window, the eighth-day fit note requirement, and the separate three-day SSP waiting period as three distinct rules that interact, not one single sickness process — mixing them up is a common and avoidable source of payroll disputes.

Sources

• gov.uk: Statutory Sick Pay (SSP)
• gov.uk: Fit notes: guidance for employers and line managers