ということ

ということ turns a whole statement into a noun: "the fact that", "that". It follows a plain-form sentence, and the result takes particles like any noun – を, が, は, に. A noun or な-adjective usually takes だ before it, never な: ×静かなということ.

ということ or こと

こと also turns a verb into a noun, but it cannot follow a noun or だ: ×学生だこと. When the content is a statement – something said, heard, known or realised – ということ is the safe choice. When it is an action you do, plain こと is usual.

• × 彼が学生だことを知らなかった → 彼が学生だということを知らなかった

Usage notes

These go beyond "the fact that".

Saying what something means

A fact followed by ということは, then a conclusion followed by ということだ, says what one fact amounts to: "A means B". As a question, ということですか checks that you have understood. This use has its own point, ということだ.

ってこと

In casual speech ということ shortens to ってこと.