From Longman Dictionary of Contemporary Englishjudging by/from somethingjudging by/from somethingGUESSused to say that you are making a guess based on what you have just seen, heard, or learned Judging by his jovial manner, he must have enjoyed his meal. Judging from what you say in your letter, you don’t sound well. → judge
Examples from the Corpus
judging by/from something• I'd say she's pretty rich, judging from her clothes. 