There is a widespread misunderstanding about obtaining your visa for Nepal. You should obtain your visa very easily at the Tribhuvan airport in Kathmandu. Foreign embassies normally charge (a lot) more for processing your passport and visa. At the airport visa will be processed in just a few minutes.
Visa can be obtained on arrival at all border entry points in Kakadvitta, Birgunj, Bhairahawa, Nepalgunj, Gaddachowki on Nepal-India border and Kodari on Nepal-China border. A valid passport and one passport -size photo with a light background is required. Immigration Department has not specified the size of the passport-size photo.
Visa can be obtained only through payment of cash in the following currency:Euro, Swiss Franc, Pound Sterling, US Dollar, Australian Dollar, Canadian Dollar, Hong Kong Dollar, Singapore Dollar and Japanese Yen. Credit card, Indian currency and Nepali currency are not accepted as payment of visa fee.
Duration 15 days, US$ 25 or equivalent convertible currency
Duration 30 days, US$ 40 or equivalent convertible currency
Duration 90 days, US$ 100 or equivalent convertible currency
Tourists can stay for a maximum of 150 days (!) in a visa year (Jan 1 to Dec 31)