Grams to Ounces Formula Explained

4 min read•June 1, 2025•Reviewed: June 1, 2026

✓Reviewed by Apex Conversion Editorial Team · Last reviewed June 1, 2026

The formula for converting grams to ounces is: oz = g ÷ 28.3495 (equivalently, g × 0.035274). The divisor comes from the exact definition of the avoirdupois ounce: 1 oz = 28.349523125 g, fixed by international agreement. This is the ounce used for food, body weight, and everyday items.

A quick mental estimate: divide grams by 28. For 100 g, that gives 3.57 oz — the correct answer is 3.527 oz, a difference of 1.2%. For larger quantities the error accumulates, so use the exact factor (0.035274) for precision work.

The Formula

oz = g ÷ 28.3495
oz = g × 0.035274  (equivalent)

Worked examples:
   28 g ÷ 28.3495 =  0.988 oz  (≈ 1 oz)
  100 g ÷ 28.3495 =  3.527 oz
  250 g ÷ 28.3495 =  8.818 oz
  454 g ÷ 28.3495 = 16.017 oz  (≈ 1 lb)
 1000 g ÷ 28.3495 = 35.274 oz  (= 1 kg)

Avoirdupois vs. Troy Ounce

Two different ounces exist. The avoirdupois ounce (28.3495 g) is used for food, body weight, shipping, and virtually all everyday contexts. The troy ounce (31.1035 g) is used exclusively for precious metals — gold, silver, platinum, and gemstones.

Using the wrong ounce introduces a ~9.7% error. A 100 g gold bar is 3.215 troy oz, not 3.527 avoirdupois oz. For everything except precious metals, use 28.3495.

Quick Reference Table

  g     oz          g      oz
──────  ──────    ──────   ──────
    5   0.176       200    7.055
   10   0.353       227    8.011  (½ lb)
   25   0.882       250    8.818
   28   0.988       300   10.582
   50   1.764       340   11.994
  100   3.527       454   16.017  (1 lb)
  113   3.986       500   17.637
  125   4.409      1000   35.274  (1 kg)