こんげつ今月kongetsu
1.

The current month that the speaker is experiencing or referencing in conversation.

2.

The month that is being referred to presently, often used in contexts related to time, finances, or events.

3.

The ongoing calendar month, distinguished from previous or future months.

Example:

今月の売り上げはよくない。

こんげつぶん今月分kongetsubun
1.

The amount owed or payment calculated for the current month.

2.

Charges or expenses that are accumulated during this month.

3.

The financial obligations or costs that pertain specifically to the present month's period.

こんげつまつ今月末kongetsumatsu
1.

The final days or concluding period of the current month.

2.

The time frame that marks the transition from this month to the next.

3.

The concluding part of the month occurring in the present calendar cycle.

Example:

今月末に僕の家にきなさい。

こんげつちゅう今月中kongetsuchuuniこんげつじゅう今月中kongetsujuuni
1.

Referring to the remaining time in the current month, indicating that something is expected to be completed or occur before the month concludes.

2.

Denoting a timeframe that suggests actions or events should take place within the ongoing month, emphasizing urgency or a deadline.

3.

Implying that a certain task or obligation must be fulfilled at some point during the present month, without specifying an exact day.