Rule 18 explained: this guide covers what it means, who it applies to, the step-by-step process, documents required, fees, due dates and penalties in India — so you can stay compliant with confidence and avoid costly mistakes.
Rule 18 is the onboarding rule for ESI. An employer must register each new employee on the specified portal before or on the day of taking him into employment; an insurance number is allotted automatically; and the employee's and family's details must be completed on a declaration form within thirty days or the number lapses.
Register the person before or on the day of joining by entering the name, Aadhaar number and other details on the specified portal, unless he is already registered under Chapter IV. An insurance number is allotted automatically and is valid for thirty days. It becomes invalid if the declaration form is not updated within thirty days or the Aadhaar is returned unauthenticated. The employer answers for the correctness of the employee's particulars, and the insured person for the correctness of his family's.
Step 1: register on or before the first day (rule 18(1))
The employer of an establishment shall, before or on the day of taking any person into employment, unless that person is already registered under Chapter IV of the Code, register him by entering his name and Aadhaar number and other details on the specified portal. An insurance number is then automatically allotted on registration and "shall remain valid for a period of thirty days".
Persons already registered under Chapter IV (for example, an employee joining from another ESI-covered employer) are not registered afresh: they are added on the specified portal by inserting the insurance number and date of appointment.
If you onboard through a payroll team or provider, make sure the registration is done on or before the joining date and not at month-end. Our ESI and PF registration service can help set up a joining checklist. The scope of who is an insured person is explained in sections 28 and 29.
Step 2: complete the declaration form (rule 18(2) and (3))
- On registration, the employer enters the updated particulars of the employee and family on the declaration form available on the specified portal.
- The Corporation provides an Aadhaar-linked identity card to the insured person and his dependent family members, electronically or otherwise.
- The insurance number automatically becomes invalid if:
- the employee's details are not updated on the Declaration form within thirty days; or
- the Aadhaar number provided by the newly employed person is returned unauthenticated by the concerned authorities.
Who is responsible for what (rule 18(4))
| Party | Responsible for |
|---|---|
| Employer | Correctness of the particulars of the employee filled on the specified portal |
| Insured person | Correctness of the particulars of his family submitted to the employer |
Because the employer is answerable for the employee's particulars, it is prudent to collect and verify identity documents at joining and to check that the Aadhaar seeding works before the thirty days end.
How the number is used (rule 18(5) and (6))
- The employer uses the insurance number for filing contributions and for all other purposes in respect of the employee.
- The employee uses it for availing any benefits available to him or his family members under the Code.
The Explanation defines "insurance number" as the number allotted by the specified portal to an employee for Chapter IV of the Code, the Central rules and the regulations made under it.
Timeline at a glance
| When | What must happen |
|---|---|
| Before or on the day of joining | Register the person with name, Aadhaar and other details (unless already registered under Chapter IV) |
| On registration | Insurance number is auto-allotted, valid for 30 days |
| Within 30 days | Declaration form updated with employee and family particulars |
| On Aadhaar failure | Number becomes invalid |
| Ongoing | Use the number for contributions and, by the employee, for claims |
A worked example
A company hires a clerk on 1 June who is not registered under Chapter IV. The HR executive enters his name, Aadhaar and other details on the portal on 1 June, and an insurance number is allotted at once, valid until thirty days later. The executive completes the declaration form with the clerk's spouse and minor child on 15 June, and an Aadhaar-linked identity card is provided to the clerk and his dependent family members. If the form had not been updated by the end of the thirty days, or if the clerk's Aadhaar had come back unauthenticated, the number would have become invalid automatically. A second hire on 10 June already has an ESI number from a previous employer; HR adds him to the portal by entering that number and his date of appointment. (Illustrative.)
What the rule does not say
The text of rule 18 does not name the portal, set any wage threshold or state a penalty for late registration. Whether a person is an employee for Chapter IV depends on the Code and the First Schedule. For consequences of non-registration or default, read the Code's penalty provisions, and see our existing post on penalties under the ESI Act for the old Act. The Central Rules apply where the Central Government is the appropriate Government; in State-sphere establishments the State's own rules apply.
Need help onboarding employees under ESI?
A missed thirty-day window means a lapsed number and a gap in cover. Our ESI and PF registration team can help you build a joining process that registers each employee on time and keeps the declaration forms complete.
Key takeaways
- Register new employees before or on the day of joining on the specified portal.
- The insurance number is auto-allotted and valid for 30 days.
- Update the declaration form within 30 days, or the number becomes invalid; an unauthenticated Aadhaar has the same effect.
- Employer is responsible for the employee's particulars; insured person for family particulars.
- Already-registered persons are added by inserting the insurance number and date of appointment.
Read next
- Sections 28 and 29: Insured persons and ESI contributions
- Rules 19 and 20: Rate of contributions and administrative expenses
- How to add a new employee on the ESIC portal
- ESI card: how to download and use
Disclaimer: Based on the Code on Social Security, 2020 (as enacted) and, where noted, the Code on Social Security (Central) Rules, 2026 (G.S.R. 344(E), 8 May 2026), as on 30 September 2026. The Code is in force from 21 November 2025; some provisions may be notified later, and State Governments make their own rules for establishments where the State is the appropriate Government. Verify the current position before acting.