The date of your actual employment, i.e when you start, should be stated in your contract. That's usually the date your employment becomes effective is what usually counts. The date you signed the offer doesn't usually matter. The date you signed the agreement and agree the terms and conditions could also be different from the date you actually start to be employed. i.e you can accept an offer in Nov 2018. You can agree to the terms and conditions in Jan 2019. But you may not actually start work and be employed for days or even weeks after signing. So really for most purposes you want the start date in your contract when you agree to the terms and conditions of your employment I wrote in "most cases", as it could depend on what you are looking at this for? What is the context?