Core answer: 1 斤 (jin) = 500 g = 0.5 kg exactly (mainland standard since 1959); 1 kg = 2 斤. So 3.5 斤 = 1.75 kg, and "I'm 120 斤" means 60 kg. Traditional subdivisions: 1 斤 = 10 两 (liang), so 1 两 = 50 g — but Hong Kong still uses 16 两 per 斤 at 605 g, and Taiwan's 斤 is 600 g.
The conversion table
| 市制 | Metric | Metric | 市制 |
|---|---|---|---|
| 1 两 | 50 g | 100 g | 2 两 |
| 1 斤 | 500 g | 1 kg | 2 斤 |
| 1 担 | 50 kg | 1 tonne | 20 担 |
| Region | 1 斤 = | 1 两 = |
|---|---|---|
| Mainland | 500 g (10 两) | 50 g |
| Taiwan (台斤) | 600 g (16 两) | 37.5 g |
| Hong Kong (司马斤) | 604.8 g (16 两) | 37.8 g |
Worked examples
Example 1 — Market shopping. Pork at ¥18/斤 = ¥36/kg. Buying 2 斤 4 两 = 1.2 kg = ¥43.2.
Example 2 — Body weight. 135 斤 = 67.5 kg; the common "好女不过百" phrase means under 50 kg — an outdated and unhealthy benchmark, by the way; healthy weight depends on height (see the BMI guide).
Example 3 — Herbal medicine. A prescription of 黄芪 30 g using old-style 两 would be misread as 30×50 = 1.5 kg in mainland units or 1.1 kg in HK units — modern prescriptions are written in grams for exactly this reason.
Example 4 — Taiwan travel. Buying fruit in Taipei at "NT$60/台斤" = NT$100/kg; a 600 g 台斤 of mangoes is not the mainland 斤.
Common mistakes and myths
- "半斤八两" confusion — the idiom ("half a jin, eight liang — equals") preserves the OLD 16-两 system where 半斤 = 8 两 exactly; under today's 10-两 system the idiom no longer computes, but the meaning stuck.
- Mixing regional 斤 — a Hong Kong recipe's "1 斤排骨" is 605 g, 21% more than the mainland 500 g.
- Assuming 两 = 50 g everywhere — precious-metal and traditional-medicine 两 differ (Troy ounce ≈ 31.1 g for gold; old 药衡 两 ≈ 31.25 g historical).
- Forgetting jin is mass, not currency — in old texts "赏金百斤" is 50 kg of bronze/gold by weight, not coins.
- Estimating freight in jin — logistics quote kg; a 300 斤 parcel is 150 kg and moves from express to freight pricing.