Default transliteration · Jack
杰克 is not a name a native would pick
If a teacher, a form, or a 'Chinese names for boys' list gave you 杰克, they gave you the dictionary row for Jack. Two graphs. No family name. Same seating-chart pipeline as 艾米丽.
What 杰克 actually is
杰克 is two transcription graphs for Jack. 杰 can appear in real given names. 克 can too. Together, with no 百家姓 in first position, they are closed-captioning. Natives hear 'the English name Jack, written in Chinese,' not a person from a family named 杰. That is a useful job for a newscaster. It is not a name.
Public classroom evidence, not a private rumor
China Daily (2016) records the pipeline at SOAS: Song Lianyi, a teaching fellow, says about fifty Western students a year are given Chinese names by teachers there — often transliteration, 'one character for the surname and one or two for their given name.' The public examples in that piece are Emily → 艾米丽 and Jack → 杰克. The Emily row already has its own check page. This is the other example from the same sentence. We will not invent a private Jack in that room.
Not 马云. Not a mint.
If you landed here because of Jack Ma: his Chinese name is 马云. The English nickname Jack on a Chinese person is the reverse pipeline. This page is an English Jack handed 杰克. Paste 杰克 at the checker on this page, or any other string at /check. Kill means: do not print the default Jack row. This site will not generate a replacement. If you want a name natives would actually use, that door is NativeChineseName.com/get — still not a generator here.
Source: The secret of a name with special character — China Daily (Wang Mingjie, 4 Oct 2016)
Holding a different string? Paste it at /check. This page will not mint a replacement. If you want a name natives would actually use, that is Get a name.