https://www.iras.gov.sg/media/docs/defa ... 9c1b2248_7
This lays out what is deductible and the required accounting if you're running a sole proprietorship or small business or partnership.
Interesting factoids - private car expenses are completely disallowed for business (even if on business) but entertainment expenses are allowed.... so take your customer out, get pissed and use a taxi.
