Great Britain, War Office Registers, 1772-1935 is a free, searchable collection hosted by FamilySearch.org.
“This collection of War Office Registers contains regimental descriptions, succession books, commissions, appointments, descriptions, returns of services, casualties, half pays, pensions, and gratuities for the years of 1772-1935. The original records are held at The National Archives in Kew, Richmond, Greater London, England. Military Records are potentially of great genealogical value and may provide information not found in any other source. Such records identify individuals who served or who were eligible to serve in the military.
Records in this collection come from the following locations:
This is an Index Only Collection meaning that you will not be able to see the actual records. Some records may be viewed at: The National Archives Image Library.”