Here is a custom formula you can use to have salesforce output the timezone of a person. It’s based on the phone number.

if( ISBLANK(Phone),”–“,

if( CONTAINS(“206:209:213:253:310:323:360:408:415:425:503:509:510:530:559:562:604:619:626:650:661:702:707:714:760:775:778:805:818:831:858:867:909:916:925:949:951:971”, left(SUBSTITUTE(SUBSTITUTE( Phone , “+1.”, “”), “(“,””),3)),”Pacific”,

if(
CONTAINS(“208:250:303:307:385403:406:435:480:505:520:602:623:719:720:780:801:928:970”, left(SUBSTITUTE(SUBSTITUTE( Phone , “+1.”, “”), “(“,””),3)),”Mountain”,

if(
CONTAINS(“204:205:210:214:217:218:224:225:228:251:254:256:262:270:281:306:308:309:312:314:316:318:319:320:325:334:337:361:402:405:409:414:417:430:432:469:479:501:504:507:512:515:563:573:580:601:605:608:612:615:618:620:630:636:641:651:660:662:682:708:712:713:715:731:763:769:773:785:806:815:816:817:830:832:847:901:903:913:915:918:920:931:936:940:952:956:972:979:985:”, left(SUBSTITUTE(SUBSTITUTE( Phone , “+1.”, “”), “(“,””),3)),”Central”,

if(
CONTAINS(“201:202:203:207:212:215:216:219:226:229:231:234:239:240:248:252:267:269:276:289:301:302:304:305:313:315:321:330:336:339:345:347:351:352:386:404:407:410:412:416:418:419:434:438:440:443:450:470:475:478:484:502:508:513:514:516:517:518:519:540:551:561:567:570:571:585:586:603:606:607:609:610:613:614:616:617:631:646:647:649:678:703:704:705:706:716:717:718:724:727:732:734:740:754:757:770:772:774:781:786:802:803:804:810:813:814:819:828:835:843:845:848:856:857:859:860:862:863:864:865:876:878:904:905:908:910:912:914:917:919:937:941:947:954:959:973:978:980”, left(SUBSTITUTE(SUBSTITUTE( Phone , “+1.”, “”), “(“,””),3)),”Eastern”,

if(
CONTAINS(“800:877:866:855:888”, left(SUBSTITUTE(SUBSTITUTE( Phone , “+1.”, “”), “(“,””),3)),”Toll Free”,”Other”

))))))