Going from Tajik to Uzbek (O'zbek) has a composite linguistic distance of 74% (heuristic estimate). Below is the dimension-by-dimension breakdown.
Shared vocabulary, cognates, and loanwords.
Morphology, syntax, word order, cases.
Shared sounds and phoneme inventory.
Cyrillic → Latin/Cyrillic
Indo-European ↔ Turkic
The 5 languages with the lowest linguistic distance from Tajik:
A quick 3-question check between Tajik and Uzbek. No signup.