Kalvaitis (Kalvaitytė, Kalvaitienė) is a Lithuanian-language surname derived from the word kalvis, "blacksmith".
It was Polonized as Kailoweit, Kallwejt, Kalwajt, Kalwajtys, Kałwajtys, Kalweit, Kallweit, Kalwejt.
[1] Notable people with this surname include: