各个州的具体规定你要自己查。联邦的，你得withhold的额度达到：

1 上年实际纳税额的110%

2 今年应纳税额的90%

这两个中间低的那个，就肯定不会被罚款，不然，可能--不是一定被罚款。第一次纳税的一般不会被罚的，你没有参照么，如果你今年收入比去年有很大增加，预扣到去年实际纳税额的110%就够了，参见irs网站。罚款具体数字，我不知道

州的我见过也是达到应该纳税额的90%就安全。

今年的withhold如果不够比例，你最迟可以在来年1月15日以前，直接把补得寄给irs，不过这个有个危险，因为按规定，你每个季度的withhold，要跟你的收入同步，如果你被发现，3月又一大笔收入，没有扣足相应比例，到了年底才补，也有罚款的可能。最好是现在就算算，如果不够，在最后几张工资单里面额外扣齐

withhold够了今年应该的90%或者上年实际的110%，就没有罚款，不足的部分4月15日以前报税补齐即可。

如果AGI超过15万（夫妻两个），就是上年实际的110%；否则就是上一年的100%

2 今年应纳税额的90%

如果两个条件都不满足，而且没有在年底前补交estimated tax的话，就会按照差价的比例罚款

[此贴子已经被作者于2005-11-20 11:53:35编辑过]

A taxpayer is required to make estimated quarterly tax payments if both of the following conditions are met:

1. $1,000 or more tax liability

one condition is met if the amount of taxes owed is expected to be $1000 or more

2, inadequate estimated payments

The other condition is met if the taxpayer's withholding is less than the lesser of:

a. 90% of current year's tax, or

b. 100% of last year's tax (use 110% of the prior year's tax liability when the taxpayers had adjusted gross income >= $150,000 in the case of married file jointly)

Withhold tax treated as estimated payments

Maximum of 25% penalty can be imposed on failure to file a tax return in time/failure to pay the tax due/accuracy related penalty (which is 20%).

MM you may be able to find more info on irs website on tax penalty