up to vs when

up to

adj
  • maximum of. 

prep
  • Until. 

  • Incumbent upon; the obligation of; the duty of. 

  • Considering all members of an equivalence class the same. 

  • Within the authority or jurisdiction of. 

  • Doing; involved in. 

  • For the option or decision of. 

  • As much as; no more than. 

  • Next to; near; towards; as far as. 

  • Ready for. 

  • Capable of. 

  • Willing to participate in. 

when

pron
  • What time; which time. 

noun
  • The time at which something happens. 

intj
  • That's enough: a command asking someone to stop adding something, especially an ingredient or portion of food or drink; used in, or as if in, literal response to 'Say when'. 

conj
  • At (or as soon as) that time that; at the (or any and every) time that; if. 

  • At what time; at which time. 

  • During the time that; at the time of the action of the following clause or participle phrase. 

  • Since; given the fact that; considering that. 

  • Whereas; although; at the same time as; in spite of the fact that. 

adv
  • At which, on which, during which: often omitted or replaced with that. 

  • A circumstance or situation in which. 

  • The time at, on or during which. 

  • At what time? At which time? Upon which occasion or circumstance? Used to introduce direct or indirect questions about time. 

  • At an earlier time and under different, usually less favorable, circumstances. 

How often have the words up to and when occurred in a corpus of books? (source: Google Ngram Viewer )