Fishing Sinker 호 ⇄ Grams Converter

Understanding the fishing sinker converter — concept and principle

Korean and Japanese fishing sinkers are sold by number, written 호 (Korean) or 号 (Japanese), instead of by grams or ounces. This converter changes a sinker number into grams and ounces, or a weight in grams back into 호, so you can follow rig instructions, compare tackle from different countries, or check that a rod's casting weight rating is not exceeded.

How it is calculated

• Grams = 호 × 3.75
• 호 = grams ÷ 3.75
• Ounces = grams ÷ 28.349523125

Results are rounded to two decimals.

The principle

The sinker number is a traditional weight unit, the monme (匁), which equals 3.75 g. The same mass is the Korean 돈, still used for gold. Japan's 1891 weights and measures law fixed the larger unit kan at exactly 3.75 kg, and one monme is a thousandth of a kan, so the factor 3.75 g is exact. The avoirdupois ounce is defined as exactly 28.349523125 g. Because 호 is simply a mass unit, the conversion is linear: doubling the number doubles the weight. This is different from fishing line numbers, where 호 relates to cross-sectional area.

Worked example

Default input: a 10호 sinker.

1. Grams: 10 × 3.75 = 37.5 g.
2. Ounces: 37.5 ÷ 28.349523125 ≈ 1.3228, shown as 1.32 oz.
3. Check: 37.5 ÷ 3.75 = 10호.

The calculator shows 37.5 g, 10호, 1.32 oz, matching these steps.

How to read the result

Heavier sinkers hold bottom in currents and wind and cast farther, but they reduce bite sensitivity and stress the rod. Light float and freshwater rigs often use well under 1호 to a few 호, while boat fishing in deep or fast water may need tens of 호; a 30호 sinker is 112.5 g. Compare the result with the casting weight printed on your rod, which is often given in grams or in 호 for Korean and Japanese rods.

Common mistakes

• Confusing the sinker 호 (a mass) with the line 호 (a diameter standard).
• Treating Western sinker sizes in ounces as 호 numbers.
• Forgetting that split shot "B" sizes (B, 2B, 3B) are a separate small-shot scale, not 호.
• Exceeding the rod's rated casting weight, which can break the rod.

Frequently asked questions

How heavy is a 30호 sinker?

30 × 3.75 = 112.5 g, about 3.97 oz.

How many 호 is 1 ounce?

About 7.56호 (28.35 ÷ 3.75).

Why 3.75 g?

1호 equals one monme, a traditional unit of exactly 3.75 g, the same as one Korean 돈.

Sources: NIST Special Publication 811, Appendix B (avoirdupois ounce = 28.349523125 g) · Japan, Weights and Measures Act of 1891 (度量衡法), 1 kan = 3.75 kg