In the Sultanate period, the army consisted mainly of cavalry, elephant corps and infantry. The cavalry was, however, the main source of strength.
According to Tarikh-e-Firuz Shahi, Jalauddin Khilji maintained 70,000 horses. Alauddin Khilji was the first Sultan to introduce the principle of Standing Army for the Sultan. That army was recruited, equipped and paid by the Sultan. There were about 4,75,000 soldiers in his standing army. Cavalry men were paid 234 Tankas for every month. The army was composed of cavalry, infantry and elephants. Among these cavalry formed the backbone of the army. Army was under the control of Diwan-i-Ariz. All the reforms introduced by Alauddin were reversed by Firuz Shah Tughlug because he followed the Jagir system. 
Ghiyasuddin Tughlaq maintained his army on the pattern and regulations of Alauddin Khalji. According to Masalik-ul-Absar, Muhammad Tughlaq’s cavalry consisted of 900,000 horsemen, double the size of that of Alauddin Khalji . Firuz Tughlaq maintained 80,000 to 90,000 well trained horses. 
Sher Shah Sur
Sher Shah maintained a powerful army comprising 150,000 horse, 25,000 foot, and 5,000 elephants, besides artillery. 
Daud Khan, proud of his army of 40,000 well mounted cavalry, 1,40,000 infantry, 3,600 elephants, and a park of artillery said to consist of 20,000 guns and thousands of war-boats. 
The exact numbers of the Mughal army cannot be definitely stated. Professor J. N. Sarkar puts the strength of Shah Jahan’s army in 1648 at 440,000, comprising 200,000 cavalry, 8,000 mansabdars, 7,000 ahadis, 40,000 infantry musketeers and artillerymen, and 185,000 cavalry commanded by princes and nobles. These numbers were exclusive of the local militia posted in the parganas and commanded by the faujdars, kroris and amlas. These militia forces were known as bumi and consisted chiefly of infantry, but occasionally included also cavalry and elephants, guns and boats. Each sarkar was responsible for its own contingent. Shah Jahan himself, in a letter written just before his captivity, speaks of being master of 900,000 troopers; but in all probability the total number actually available for service in the field was less than this. In Akbar’s day, at any rate, no precise estimate of the total Mughal military strength can be given; the cavalry, in which Pathans and Rajputs predominated, may have numbered about 250,000 but sufficient trustworthy data are not available for rest of the forces .
1- Indian Administration, N. Jayapalan – Page 24
2- Theory and Practice of Muslim State in India -Kishori Saran Lal- Page 171
3- Historical Forts In Pakistan – Page 5
4- History of Medieval India: From 1000 A.D. to 1707 A.D. – Page 182
5- Medieval India: From Sultanat to the Mughals Part – II – Page 109
6- 4- Mughal Rule in India – Stephen Meredyth Edwardes- Page 178