It is narrated from Hazrat Ibn Khnabash Tai (may Allah be pleased with him) that once I was sitting in the company of the Prophet (peace and blessings be upon him) when a woman came and said, "O Messenger of Allah! In which month should I perform Umrah?" The Prophet (peace and blessings be upon him) said, "Perform Umrah in the month of Ramadan, for performing Umrah in Ramadan is equal to Hajj."
Hadith Referenceمسند احمد / مسند الشاميين / 17600
Hadith Gradingحکم دارالسلام:حديث صحيح، وهذا إسناد ضعيف لضعف داود الأودي، وأخطأ داود فى تسمية الصحابي فسماه هرما، والجادة وهب