| Line Item | Sep 30, 2025 | Sep 30, 2024 | Sep 30, 2023 | Sep 30, 2022 | Sep 30, 2021 | Sep 30, 2020 | Sep 30, 2019 | Sep 30, 2018 |
|---|---|---|---|---|---|---|---|---|
| Unaudited Condensed Consolidated Statements of Operations and Comprehensive Loss | ||||||||
| Sales to third parties | ||||||||
| Sales to related parties | ||||||||
| Revenues | ||||||||
| YoY growth | -56.4% | |||||||
| Cost of revenues | ||||||||
| Gross (loss) profit | ||||||||
| % of revenue | 2.9% | |||||||
| Operating expenses | ||||||||
| (Allowance) reversal of allowance for credit losses | ||||||||
| Selling and distribution expenses | ||||||||
| General and administrative expenses | ||||||||
| Total operating expenses | ||||||||
| % of revenue | -203.5% | |||||||
| Loss from operations | ||||||||
| % of revenue | -200.6% | |||||||
| Other income, net | ||||||||
| Interest Income | ||||||||
| Interest expense | ||||||||
| Amortization of debt issuance costs | ||||||||
| Total other income, net | — | |||||||
| Loss before income taxes | ||||||||
| Income Tax Expense | ||||||||
| Net loss | ||||||||
| % of revenue | -190.9% | |||||||
| Net loss attributable to non-controlling interest | ||||||||
| Net loss attributable to Farmmi, Inc. | ||||||||
| % of revenue | -189.8% | |||||||
| Comprehensive loss attributable to non-controlling interest | — | |||||||
| Comprehensive loss attributable to Farmmi, Inc. | ||||||||
| Basic | ||||||||
| Diluted |