# Tax deduction

> Subtracting business expense from taxable income to lower tax owed.

**URL:** https://quilometragem.com/glossary/tax-deduction

**Summary:** Subtracting business expense from taxable income to lower tax owed.

- A tax deduction is the legal mechanism to subtract a business expense from taxable income.
- Documented mileage — with origin, destination, distance, business purpose, and amount — is deductible in most regimes: US Schedule C, Brazilian IRPF via Livro Caixa, Mexican ISR under RESICO or Actividad Empresarial.
- The deduction requires contemporaneous documentation; later reconstruction is rarely accepted in audit.

A tax deduction is the legal mechanism to subtract a business expense from taxable income. Documented mileage — with origin, destination, distance, business purpose, and amount — is deductible in most regimes: US Schedule C, Brazilian IRPF via Livro Caixa, Mexican ISR under RESICO or Actividad Empresarial. The deduction requires contemporaneous documentation; later reconstruction is rarely accepted in audit.