You are the boss.
你是老板，（你说了算）。

You have the conn.
你说了算。
Conn本来是“掌舵”的意思，后来被当作名词用，to have the conn就是负责控制舰艇行驶的方向，也就是“有决定权“的意思。

You have the final say.
你决定吧。

It's all up to you.
全听你的了。

The final decision is yours.
你做最后定夺吧。

You are in charge here.
你是这里管事儿的。

You are the one who call the tune in this house.
在这里，你说了算。

Who wears the trousers in your house? You or your wife?
在你家里谁说了算，你还是你妻子？

I am the decider of my house.
在家里我说了算。