请问一下OPT开始时间怎么算，是I20上时间还是EAD卡上时间

请教一下大家，我是第二个master degree，第一个master是非stem，五月十二号毕业一个多月的时候六月中旬才申请opt，I20上opt开始时间是7月初，结果EAD卡批下来都十月初了，但是expires date是第二年七月十一日，等于EAD有效时间只有九个月。想问一下大家，OPT开始的时间到底是哪个啊？是7月还是EAD卡批下来的十月啊？我在想我有没有可能在申一下OPT能不能再批三个月，不知道有没有操作性。有相同case的同学麻烦赐教，谢谢大家！

你拿到EAD的十月开始，相当于你少了三个月

这个应该是根据I20上来的哦。。。

你的I-20和EAD是一致的呀 都是明年7月到期 而且不能在重新申请三个月了 只能怪自己当时不够上心吧

Well, you applied for OPT on June to request a start date from July. That's the problem.
From USCIS or your school international student office website, they will tell you that the regular processing time for USCIS to handle a case is approximate 3 months. That is, you will not get your OPT approved before Sep or Oct.
OPT start date is decided by the later one of your request time and approve date by USCIS. Your request time is July and OPT approve date is Oct. So your OPT will begin from Oct.
However, OPT expire date is strictly limited by your I-20. Actually, the valid start date for you to request for OPT is within 60 days after you graduate. So the latest date you can request will be on July. According to this, I-20 your school approves will start from July and end after one year. That is, your OPT expire date is July next year. And you have no way to request more time for current OPT but to apply for OPT STEM extension if you are in STEM major.
The start date and expire date are both on your EAD card and between those date is your valid working period. 3 months you waste is due to your late application by your fault.