Unless you are from India, a visa is necessary to enter Nepal.
Nationals from Bangladesh, Bhutan, Maldives, Pakistan and Sri Lanka can obtain a visa on arrival for free. The visa is valid for 30 days
Nationals from Afghanistan, Cameroon, Ethiopia, Ghana, Iraq, Liberia, Nigeria, Palestine, Somalia, Swaziland, Syria and Zimbabwe need to arrange a visa before arriving.
Multiple entry tourist visas can be obtained by paying US$30 for 15 days, US$50 for 30 days or US$125 for 90 days. You will need a recent passport photo.
Visitors may extend their tourist visa by paying US $2 per day. You may not stay longer that 150 days per calender year or will have to pay a fine.Trekking permits are not required for Everest, Annapurna and Langtang areas. Business visas with multiple entry facilities are available at a rate of US $100 for one year and US $250 for five years. Ministry of Industry recommendation is required. Visas are free for all tourists who come from a SAARC country. Indian nationals do not need a visa.
Nepal Visa Information