有点儿累。

Place it after the subject of your sentence. You can say 我有点儿累 to mean 'I am a bit tired.' It works as a standalone answer too. If someone asks how you are, this is a very common reply. It sounds natural and very human. You do not need any extra grammar particles here.

Use it after a long day at the office. Use it after a three-hour hike. It is perfect for texting a friend to decline an invite. It works well when you want to leave a party early. It is honest but keeps things light. It is great for everyday life in China.

Do not use it if you are truly exhausted. If you just ran a marathon, use 累死了 instead. Avoid using it in high-stakes job interviews. You want to sound energetic there, not sleepy! Also, do not use it to describe others unless you are sure. It might sound like you are criticizing their work ethic.

Chinese culture often values modesty and emotional restraint. Saying you are 'a little' tired is often a polite understatement. Even if you are very tired, starting with 有点儿 feels more humble. It gives the other person space to offer sympathy. It is a social lubricant that avoids sounding too demanding or negative.

In Southern China, people often drop the 'r' sound. They will say 有点累 instead of 有点儿累. Both are perfectly correct and understood everywhere. If you want to sound more intense, try 太累了. If you are just slightly sleepy, you might say 有点儿困. Keep these in your back pocket for variety!