One of the trickiest options to figure out is business casual simply because the two are really very different looks, business vs. casual. When successfully done it is a comfortable mix of clothing that exudes confidence and competence. A question you need to ask yourself is where does your office fall on the definition of what business causal means? It’s very important to understand what they expect because everyone’s definition is different.
For the company that prefers the more business side of business casual you could pair your more formal attire with a dark denim to make the business to happy hour transition. For the company that leans more on the casual side you will want to maintain the basic elements of a suit however you can lose the tie and swap out your dress trousers for a pair of chinos this is a great year round look, but really looks fantastic in the summer. If your company falls in the middle, you can easily pull off a dress shirt and a pair of chinos to provide a great business casual look.