How many years were there between Adam and Muhammad (peace be upon them both)?
Question

How long was the period of time between the creation of Adam (peace be upon him) and the creation of Muhammad (peace and blessings of Allah be upon him)?
Praise be to Allah.There is nothing in Islam that defines the period between Adam and Muhammad (peace be upon them both); indeed the length of time that Adam (peace be upon him) lived is not known. 
But there are some ahaadeeth and reports which, if we put them together, we can arriver at an approximate length of time, but that not cover the complete period. Some of these ahaadeeth and reports are saheeh (sound) and others are subject to differences of scholarly opinion, and some periods of time are not defined precisely in any reports. Among the saheeh reports concerning that are the following: 
1 – Allah says concerning the length of time that Nooh (peace be upon him) remained calling his people: 
“and he stayed among them a thousand years less fifty years”
[Al-‘Ankaboot 29:14]
2 – The period between ‘Eesa and our Prophet (peace be upon them both): al-Bukhaari narrated that Salmaan al-Faarisi said: “The period between ‘Eesa and our Prophet (peace be upon them both) was six hundred years.” There are also other reports whose soundness is debatable, which mention the following:  
3 – The period between Adam and Nooh (peace be upon them both): it was narrated from Abu Umaamah that a man said: “O Messenger of Allah, was Adam a Prophet?” He said, “Yes, and Allah spoke to him.” The man asked, “How much (time) was there between him and Nooh?” He said, “Ten centuries.” Narrated by Ibn Hibbaan in his Saheeh, 14/69; and by al-Haakim, 2/262. He said it is saheeh according to the conditions of Muslim, and al-Dhahabi agreed with him. Ibn Katheer said in al-Bidaayah wa’l-Nihaayah (1/94): this is (saheeh) according to the conditions of Muslim, even though he did not narrate it. 
4 – The period between Nooh and Ibraaheem (peace be upon them both): our evidence is in the continuation of the hadeeth of Abu Umaamah (may Allah be pleased with him) quoted above: … He said, “And how long was there between Nooh and Ibraaheem?” He said, “Ten centuries.” (Narrated by al-Haakim in al-Mustadrak, 2/288. He said: this hadeeth is saheeh according to the conditions of Muslim, although he did not narrate it. And it was narrated by al-Tabaraani in al-Mu’jam al-Kabeer, 8/118. 
It was reported that some of the narrators of this hadeeth were da’eef (weak), but al-Albaani classed it as saheeh on the basis of corroborating reports. 
Some of the reports that were narrated include the following: 
5. The period between Moosa and ‘Eesa (peace be upon them both). Al-Qurtubi said: there was some difference of opinion as to the length of this period. Muhammad ibn Sa’d mentioned in his book al-Tabaqaat that Ibn ‘Abbaas said: “between Moosa ibn ‘Imraan and ‘Eesa ibn Maryam (peace be upon them both) there were one thousand and seven hundred years, and there was no fatrah (interval when no Prophet was sent) between them, for one thousand Prophets of the Children of Israel were sent between them, apart from other Prophets who were also sent (to other nations). And between the birth of ‘Eesa and the Prophet (peace and blessings of Allah be upon him) there were five hundred and ninety-nine years.” (Tafseer al-Qurtubi, 6/121). Ibn Hajar said: “The narrators are agreed that the period of the Jews until the coming of the Prophet (peace and blessings of Allah be upon him) was more than two thousand years, and the period of the Christians until the coming of the Prophet (peace and blessings of Allah be upon him) was six hundred years.” (Fath al-Baari, 4/449) 
By looking at the verse, ahaadeeth, reports and opinions quoted above, if they are correct then we may use them to work out the period in question. 
But as for being certain of the length of time between Adam and Muhammad (peace be upon them both), then in addition to the above there are many other considerations to be addressed before we can work it out, including the following: 
·Differences of scholarly opinion concerning the definition of the word qarn (translated above as “century”) – does it mean one hundred years, or does it mean one generation? What we know is that the lifespan of the people at that time was a fraction of the time that Nooh spent in calling his people, and we do not know how long the people of those generations lived.
·There is no report which defines the number of years between Ibraaheem and Moosa (peace be upon them both).
 It remains to be said that being certain about such matters or researching them are not things on which we base our acts of worship or our actions, and the words of Allah are sufficient for us:                                                                                  
“And (also) ‘Aad and Thamood, and the Dwellers of Ar-Rass, and many generations in between”
[Al-Furqaan 25:38 – interpretation of the meaning]
 We must strive to follow the example of these Prophets and walk in their footsteps, because this is the purpose behind mentioning them and their lives:
“They are those whom Allah had guided. So follow their guidance” [Al-An’aam 6:90]
 And Allah knows best.