Price per Jin vs per Kilogram: Which Quote Is Cheaper?

Why you double the price but halve the weight

A modern mainland jin is 500 g, so a kilogram contains two jin. If each jin costs 18 yuan, a kilogram costs 18 + 18 = 36 yuan. To convert the weight, however, 3 jin × 0.5 = 1.5 kg. The two calculations go in opposite directions because one changes the quantity and the other changes the quantity covered by a price.

For this guide, the prices are sample quotes in CNY. Before using the same calculation on a listing, check that its price really is per 斤 or per 公斤/千克. A bag price, a tray price and a price per 500 g can look similar on a small product card.

Four formulas for a mainland market quote

Keep price and quantity in matching units. At 18 CNY/jin, buying 3 jin costs 54 CNY. Alternatively, convert both sides: 36 CNY/kg × 1.5 kg also gives 54 CNY. If the totals differ, a unit or a price basis has probably been mixed up.

Two sellers, one shopping list

You want 1.5 kg of the same product. Seller A quotes 18 CNY per jin with no delivery charge. Seller B quotes 32 CNY per kilogram plus 8 CNY delivery.

• Seller A: 1.5 kg = 3 jin; 3 × 18 = 54 CNY.
• Seller B: 1.5 × 32 = 48 CNY for the product; 48 + 8 = 56 CNY delivered.

B's product costs 6 CNY less, but A's delivered total is 2 CNY lower. Keeping delivery as a separate line makes the reason visible.

Now increase the order to 3 kg. A costs 3 × 36 = 108 CNY. B costs 3 × 32 + 8 = 104 CNY. With these quotes, the cheaper option changes as the quantity changes.

At what quantity does the delivery fee pay off?

B saves 4 CNY per kilogram on the product and charges 8 CNY for delivery. Divide the extra fee by the saving per kilogram:

8 ÷ 4 = 2 kg.

At 2 kg, both delivered totals are 72 CNY. Below 2 kg, A is cheaper; above 2 kg, B is cheaper, provided those prices and delivery charges stay the same. This shortcut is useful when you are deciding whether to combine purchases into one order.

Recalculate if a delivery threshold, minimum order or discount changes. Also compare net product weight. Paying less per kilogram does not help if the quoted weight includes packaging that the other seller excludes.

Check the region before using a catty quote

The 500 g rule applies to the modern mainland jin. Taiwan's tai-jin is 600 g; Hong Kong's sima catty is 604.78982 g. If one catty is k kilograms, divide the price per catty by k to get the price per kilogram.

For example, a quote of 60 currency units per Taiwan tai-jin gives 60 ÷ 0.6 = 100 units/kg. The same number quoted per mainland jin gives 60 ÷ 0.5 = 120 units/kg. Keep the currency fixed for that comparison: 60 TWD, 60 HKD and 60 CNY are different amounts of money.

Select the seller's definition in the regional catty converter. A historical document or an unexplained overseas listing needs its own unit definition; the English word catty does not settle it.

Keep a short calculation with the order

A useful note is: “18 CNY per mainland jin × 3 jin = 54 CNY; net weight 1.5 kg; delivery included.” Add the item, seller, quote date and any conditions. This is enough to check the checkout total or explain a mismatch without reconstructing the calculation later.

The price module on Jin to KG handles the mainland price basis and quantity. If you need a foreign-currency estimate, convert the final CNY total with the dated currency tool. Retain the rate's observation date and compare any actual payment-provider fees separately.

References

• Taizhou government local-history reference: standard measurement — Reference for the modern mainland 500 g jin. The shopping prices and delivery examples are illustrative.
• Taiwan BSMI measurement reference (PDF) — Reference for Taiwan weight units, including the 600 g tai-jin.
• Hong Kong Chinese Medicine Council: manufacturing guide, Appendix 2 (PDF) — Sima catty weight definition used for the regional comparison.

References checked 2026-10-26.

Related tools and reading

• Jin to KG Converter (斤 to kg)
• Catty to Pounds & KG: Mainland, Hong Kong, Taiwan
• Chinese Units Conversion Chart | Jin, Mu, Li, Chi