Annual report pursuant to Section 13 and 15(d)

Document And Entity Information

v3.22.1
Document And Entity Information - USD ($)
 12 Months Ended
Dec. 31, 2021
Mar. 15, 2022
Jun. 30, 2021
Document Information [Line Items]      
Entity Central Index Key 0001881592    
Entity Registrant Name NSTS Bancorp, Inc.    
Amendment Flag false    
Current Fiscal Year End Date --12-31    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2021    
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2021    
Document Transition Report false    
Entity File Number 001-41232    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 87-2522769    
Entity Address, Address Line One 700 S. Lewis Ave.    
Entity Address, City or Town Waukegan    
Entity Address, State or Province IL    
Entity Address, Postal Zip Code 60085    
City Area Code 847    
Local Phone Number 336-4430    
Title of 12(b) Security Common Stock, par value $0.01 share    
Trading Symbol NSTS    
Security Exchange Name NASDAQ    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status No    
Entity Interactive Data Current Yes    
Entity Filer Category Non-accelerated Filer    
Entity Small Business true    
Entity Emerging Growth Company true    
Entity Ex Transition Period false    
ICFR Auditor Attestation Flag false    
Entity Shell Company false    
Entity Public Float     $ 0
Entity Common Stock, Shares Outstanding   5,397,959  
Auditor Name Plante & Moran, PLLC    
Auditor Location Chicago, Illinois    
Auditor Firm ID 166