Tax self-examination generally does not exceed 400 yuan. For the annual income below120,000, the amount of supplementary tax does not exceed that of 400 yuan, which is tax-free. Tax self-examination and tax payment refers to an inspection method in which the competent tax bureau or inspection bureau of an enterprise notifies the enterprise to carry out its own inspection and then returns it to the tax authorities, and makes corresponding tax payment according to the self-examination results of the enterprise.