how much; how many; what amount; what extent
A somewhat literary or formal way to ask about quantity, degree, or extent. Often used in written language or set phrases.
残された時間は幾ばくもない。
There is not much time left.
その価値は幾ばくかと問われれば、答えに窮する。
If asked how much it is worth, I would be at a loss for an answer.
どれほど is a standard way to ask 'how much' or 'to what extent', while 幾ばく carries a more formal, sometimes archaic tone.
Mixed kanji-kana spelling; usually written in kana.
Kana spelling is the most common and recommended for learners.
Full kanji form; rarely used in modern writing.
Rarely used kanji form; easily confused with 幾何 (きか, geometry).
Compound of 幾 (iku, 'how many') + ばく (baku, an old suffix indicating amount or degree). The suffix ばく is of uncertain origin but appears in classical Japanese.