Basis of Presentation	9 Months Ended
Sep. 30, 2018
Basis Of Accounting [Abstract]
Basis of Presentation	Note 1: Basis of Presentation The accompanying unaudited consolidated financial statements of FSB Bancorp, Inc. (“FSB Bancorp”), Fairport Savings Bank (the “Bank”), and its other wholly owned subsidiary, Fairport Wealth Management (collectively, the “Company”), have been prepared in accordance with accounting principles generally accepted in the United States of America for interim financial information, the instructions for Form 10-Q and Article 8 of Regulation S-X. Accordingly, they do not include all of the information and footnotes necessary for a complete presentation of consolidated financial condition, results of operations and cash flows in conformity with generally accepted accounting principles. In the opinion of management, all adjustments, consisting of normal recurring accruals considered necessary for a fair presentation, have been included. The results are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 or for any future period. The Company's consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States and follow practices within the banking industry. Application of these principles requires management to make estimates, assumptions, and judgments that affect the amounts reported in the consolidated financial statements and accompanying notes. These estimates, assumptions, and judgments are based on information available as of the date of the financial statements; accordingly, as this information changes, the financial statements could reflect different estimates, assumptions, and judgments. Certain policies inherently have a greater reliance on the use of estimates, assumptions, and judgments and as such have a greater possibility of producing results that could be materially different than originally reported. Estimates, assumptions, and judgments are necessary when assets and liabilities are required to be recorded at fair value or when an asset or liability needs to be recorded contingent upon a future event. Carrying assets and liabilities at fair value inherently results in more financial statement volatility. The fair values and information used to record valuation adjustments for certain assets and liabilities are based on quoted market prices or are provided by other third-party sources, when available. When third party information is not available, valuation adjustments are estimated in good faith by management.

Basis of Presentation

9 Months Ended

Sep. 30, 2018

Note 1: Basis of Presentation

The accompanying unaudited consolidated financial statements of FSB Bancorp, Inc. (“FSB Bancorp”), Fairport Savings Bank (the “Bank”), and its other wholly owned subsidiary, Fairport Wealth Management (collectively, the “Company”), have been prepared in accordance with accounting principles generally accepted in the United States of America for interim financial information, the instructions for Form 10-Q and Article 8 of Regulation S-X. Accordingly, they do not include all of the information and footnotes necessary for a complete presentation of consolidated financial condition, results of operations and cash flows in conformity with generally accepted accounting principles. In the opinion of management, all adjustments, consisting of normal recurring accruals considered necessary for a fair presentation, have been included. The results are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 or for any future period.

The Company's consolidated financial statements are prepared in accordance with accounting principles generally accepted in the United States and follow practices within the banking industry. Application of these principles requires management to make estimates, assumptions, and judgments that affect the amounts reported in the consolidated financial statements and accompanying notes. These estimates, assumptions, and judgments are based on information available as of the date of the financial statements; accordingly, as this information changes, the financial statements could reflect different estimates, assumptions, and judgments. Certain policies inherently have a greater reliance on the use of estimates, assumptions, and judgments and as such have a greater possibility of producing results that could be materially different than originally reported. Estimates, assumptions, and judgments are necessary when assets and liabilities are required to be recorded at fair value or when an asset or liability needs to be recorded contingent upon a future event. Carrying assets and liabilities at fair value inherently results in more financial statement volatility. The fair values and information used to record valuation adjustments for certain assets and liabilities are based on quoted market prices or are provided by other third-party sources, when available. When third party information is not available, valuation adjustments are estimated in good faith by management.