Most US employees do not have a written employment contract. They work on an at-will basis, meaning either side can end the relationship at any time for any lawful reason, and instead receive a written offer letter setting out the basic terms. Written contracts are usual for senior, specialist and fixed-term roles. Because employment law is set largely at the state level, the rules vary from state to state, so what is compliant in one state may not be in another. The details below matter whether you are hiring in the US or relocating for a role.
Employment contracts work differently in the United States than almost anywhere else, and the differences catch out businesses and professionals arriving from more codified markets. There is usually no written contract, employment is mostly at-will, and the rules shift from one state to the next. For energy employers hiring across US states, and for international professionals taking up US roles, understanding how this works is essential. This guide explains the US contract landscape and pairs with our broader guide to working in the USA.
This guide reflects US federal law and common practice as of 2026, with state-level variation noted. Employment law differs significantly by state and changes over time, and this is informational only, not legal advice.
Do US employees have written employment contracts?
Usually not. The majority of US workers are employed at-will without a written employment contract and instead receive a written offer letter setting out the basic terms and conditions: role, pay, start date and reporting line. Because employment law varies by state, there is no single federal rule on what an offer letter must contain. Some states add their own requirements. New York, for example, requires employers to give written notice of pay details at the point of hire, and to repeat that notice annually, under its Wage Theft Prevention Act. Written employment contracts are typically reserved for highly skilled or senior employees, such as executives, and for fixed-term roles.
What is at-will employment?
At-will employment means either the employer or the employee can end the relationship at any time, for any lawful reason, with no notice and no statutory severance. It is the standard in every US state except Montana, which by statute requires good cause to dismiss an employee once they have completed a probationary period. At-will is not unlimited even elsewhere: an employer cannot dismiss someone for an unlawful reason such as discrimination or retaliation, and most states recognise further exceptions, for example, where an employee handbook or offer letter creates an implied promise of job security. Documentation and consistent process, therefore, matter, even in a strongly at-will state.
What types of employment contracts exist in the USA?
US working arrangements generally fall into four categories:
- Permanent, at-will employment. The default. Either party can end it at any time without cause, subject to anti-discrimination and other legal limits.
- Fixed-term contracts. Less common, used for specific projects or time-limited roles, which suits a good deal of project-based energy work.
- Independent contractors. Self-employed individuals providing services under a contract for a defined period or project. Classification here is heavily scrutinised, as covered in our guide to choosing between contractors and an employed workforce.
- Part-time and temporary work. More limited hours, often seasonal or short-term.
Can a US employment contract or its terms be changed?
For at-will employees without a written contract defining their exact role, pay and benefits, employers can generally change the terms of employment going forward, provided the change is not discriminatory or otherwise unlawful and any required notice is given. Where an employee is on a signed written contract, its terms govern, and changes need to be agreed rather than imposed. This is one of the practical reasons senior hires negotiate written contracts: they lock in terms that an at-will arrangement leaves open.
What goes into a written US employment contract?
Where a role does use a written contract, it must comply with federal and applicable state law on matters including:
- There is no federally mandated maximum. Ninety days is the most common period, though it can be extended, sometimes up to twelve months.
- Working hours. The standard full-time week is 40 hours over five days.
- Under the Fair Labor Standards Act, non-exempt employees must be paid 1.5 times their regular rate beyond 40 hours a week. Many salaried managerial and professional roles are exempt.
Contracts for senior roles often also cover confidentiality, non-solicitation, arbitration and cause provisions, all of which vary in enforceability by state.
Why does state-by-state variation matter so much?
Because there is no single US employment law. Tax, leave, final-pay timing, notice requirements and the enforceability of contract clauses all differ by state, and a combined US workforce can suddenly span several jurisdictions at once, which is common in the energy sector. Federal law sets a baseline through the FLSA, and anti-discrimination statutes enforced by agencies such as the EEOC and the Department of Labor, but the state layer is where compliance gets detailed. This is also a live area: our guide to US labour law changes in 2026 covers the federal contractor-classification rule and other shifts currently in motion.
What should energy employers and candidates know?
For employers, the essentials are that at-will offers flexibility but does not remove discrimination or wrongful-termination exposure, that multi-state hiring means tracking different state rules on pay notices, final pay and clause enforceability, and that classification of contractors must be handled carefully. Clear offer letters and, for senior roles, well-drafted contracts are the best protection. For candidates, especially those relocating internationally, the absence of a written contract and of statutory notice or severance is the biggest adjustment. Read your offer letter closely, understand which state’s rules apply, and for senior roles, consider negotiating a written contract.
How WRS supports compliant US hiring
WRS combines global energy recruitment with a genuine US presence, headquartered in Tampa, Florida, with a hub in Houston, Texas and support for roles nationwide. We help energy employers hire compliantly across US states, getting offer letters, contracts and worker classification right, and we support candidates through the realities of US engagement. Our recruitment solutions and contractor services cover compliant hiring, classification and payroll across multiple states, and as an Employer of Record, we can employ people on your behalf where you have no entity. Explore our oil and gas, US construction and contract roles to see where we are active.
If you are hiring in the US or relocating for a role, get in touch to talk it through, or visit worldwide-rs.com to learn more.
FAQs
Do US employees need a written employment contract?
No. Most US employees work at-will without a written contract and receive a written offer letter instead. Written contracts are usual for senior, specialist and fixed-term roles. Some states, such as New York, require specific written pay notices at hire regardless.
What is at-will employment in the USA?
At-will means either party can end employment at any time for any lawful reason, with no notice or statutory severance. It applies in every state except Montana, which requires good cause to dismiss after a probationary period. Exceptions for discrimination, retaliation and implied contracts apply across states.
Can a US employer change the terms of employment?
For at-will employees without a written contract, employers can generally change terms going forward, as long as the change is lawful and any required notice is given. Where a signed written contract exists, its terms govern, and changes must be agreed.
How long is a probationary period in the USA?
There is no federally mandated maximum. Ninety days is most common, though it can be extended, sometimes up to twelve months, depending on the employer and role.
How can WRS help with US employment contracts?
WRS helps energy employers hire compliantly across US states, including offer letters, contracts, worker classification and payroll, from US hubs in Tampa and Houston, and can act as Employer of Record where you have no entity. Visit worldwide-rs.com or contact us to discuss your needs.
