Verification: factors follow standard unit definitions; round for display only.

Grams to ounces

Convert g to oz when a kitchen scale, EU nutrition label, lab balance, or jewelry spec lists mass in grams but you need US avoirdupois ounces for recipes, postage tiers, FDA-style serving sizes, or retail weight tags.

The gram (g) is the SI unit of mass at kitchen and label scale; the ounce (oz) is the standard avoirdupois subdivision of the pound in US commerce. Because 1 lb = exactly 16 oz = 453.59237 g, one avoirdupois ounce is fixed at:

oz = g ÷ 28.349523125  ·  equivalently   oz = g × 0.03527396195

The inverse is also exact: 1 oz = 28.349523125 g. For display, dividing by 28.35 is a common rounded shortcut. The calculator above uses the full defined factor; the steps below help you verify spreadsheet formulas or scale readouts.

Step-by-step conversion (worked example — baking)

Convert 250 g of flour to ounces — a typical single-cake batch weight:

1. Write the formula: oz = g ÷ 28.349523125
2. Divide: 250 ÷ 28.349523125 = 8.818490487 oz
3. Round for display: 8.82 oz (or 8 oz 13.1 dr in strict lb-oz notation)

If your US recipe lists “9 oz flour,” 250 g is slightly under — scale up by about 2 g or accept the small difference for home baking.

Second worked example (nutrition label)

Convert 28 g — a common US reference serving size on snack packaging:

1. 28 ÷ 28.349523125 = 0.987670934 oz
2. Round to two decimals: 0.99 oz

Labels often round to “1 oz (28 g)” because 28 g is within FDA rounding tolerance for the dual declaration. The exact ounce value is just under 1 oz.

Third worked example (postage)

Convert 100 g — a small padded envelope weighed on a metric scale:

1. 100 ÷ 28.349523125 = 3.527396195 oz
2. Round up for rate tables: 3.53 oz

USPS domestic letter rates step by ounce. A 100 g piece clears 3 oz but not 4 oz — convert before comparing against ounce-based rate charts rather than guessing from grams.

Quick mental estimate (no calculator)

For rough checks, divide grams by 30 or multiply by 0.035. Example: 150 g → 150 ÷ 30 = 5 oz (exact: 5.291 oz). Dividing by 28.35 is tighter. The ÷30 shortcut runs about 5% low — fine for pantry estimates, but use the full divisor for postage, nutrition compliance, or jewelry buy/sell quotes.

Gram to ounce conversion chart

Where grams → ounces comes up

• Cooking & baking: Metric recipes and EU packaging list ingredients in grams; US cookbooks and some older kitchen scales still show ounces. Convert the total ingredient mass first, then split into pounds and ounces via pounds to ounces if a recipe calls for “8 oz plus 2 oz.”
• Postage & small parcels: Kitchen and postal scales in Europe read grams; US carrier rate cards (USPS, UPS SurePost tiers) often quote ounce breakpoints. Weigh in one system, convert once, then compare against the rate table.
• Jewelry & precious metals: Bullion listings and assay certificates may show net weight in grams while US retail tags use avoirdupois ounces. Note: troy ounces (used for gold and silver spot price) are heavier — 1 troy oz = 31.1034768 g. This converter uses avoirdupois ounces only.
• Nutrition labels: FDA-style panels show dual “oz (g)” declarations. Imported EU products list grams first; converting lets you compare serving sizes against US products quoted per ounce.

Ounces to grams

Convert oz to g when a US recipe, postage receipt, jewelry tag, or nutrition panel lists avoirdupois ounces but your scale, lab notebook, or EU supplier sheet expects grams.

Reverse the grams-to-ounces process by multiplying ounces by the exact definition factor. Both routes are equivalent because the avoirdupois ounce mass is fixed in grams.

g = oz × 28.349523125  ·  equivalently   g = oz ÷ 0.03527396195

Step-by-step conversion (worked example)

Convert 4 oz (a quarter-pound stick of butter) to grams:

1. Multiply: 4 × 28.349523125 = 113.3980925 g
2. Round for display: 113.4 g

Many US butter wrappers mark 113 g / 4 oz / ¼ lb — all consistent with the defined relationship.

Second worked example (jewelry)

Convert 0.5 oz of silver sheet stock to grams:

1. 0.5 × 28.349523125 = 14.1747615625 g
2. Round: 14.17 g

Quick mental estimate (reverse direction)

Approximation: multiply ounces by 28 or 30. Example: 6 oz → 6 × 28 = 168 g (exact: 170.10 g). Multiplying by 28 runs slightly low; 30 runs high. Split the difference with 28.35 for better accuracy.

Quick reference (oz → g)

Reverse conversion is essential when US ounce-first supplier sheets feed metric inventory systems, or when you reconcile ounce-based postage quotes with gram weigh-ins from a precision scale.

Avoirdupois vs troy, common mistakes, and related tools

The g–oz factor is exact by international definition. Avoid troy-ounce confusion, verify with anchor values, and keep mass distinct from fluid ounces.

Grams vs avoirdupois ounces at a glance

Avoirdupois ounce vs troy ounce (jewelry context)

US grocery, postage, and recipe ounces are avoirdupois (28.349523125 g). Gold and silver spot prices quote troy ounces (31.1034768 g). A 28 g metric bar is almost exactly 1 avoirdupois oz but only about 0.90 troy oz. Always confirm which ounce a dealer or assay report uses before converting for a transaction.

Common mistakes to avoid

• Using 28 g as exactly 1 oz — close for label rounding, but 1 oz = 28.349523125 g. On a 500 g shipment the gap is about 6 g (~0.2 oz), enough to cross a postage tier.
• Confusing fluid ounces (fl oz) with weight ounces — fl oz measure volume. A fluid ounce of honey weighs more than 1 oz; a fluid ounce of oil weighs less. This tool converts mass only.
• Applying troy ounces to cooking or postage — recipes and USPS tiers use avoirdupois ounces. Troy ounces appear in bullion and some gem-weight traditions.
• Rounding each ingredient before summing — convert or weigh the full batch, then divide. Per-ingredient rounding drifts totals in large catering batches.
• Mixing metric tonnes with ounces directly — convert through grams or kilograms. See kilograms to grams for kg ↔ g, then apply the oz factor.
• Ignoring scale tare weight — zero the container before converting the net grams readout; packaging mass can push a parcel into the next ounce rate band.

Exactness and round-trip verification

Because 1 oz is defined as exactly 28.349523125 g under the 1959 international yard-and-pound agreement, the conversion is not an empirical approximation. Converting 100 g → 3.527 oz → 100 g should recover the original within floating-point limits. Sanity checks: 28.35 g ≈ 1 oz, 454 g ≈ 16 oz (1 lb), 113.4 g ≈ 4 oz.

Related weight converters

For the inverse of this page, open ounces to grams. Nearby workflows: kilograms to pounds, pounds to ounces, kilograms to grams, kilograms to ounces, grams to pounds, and milligrams to ounces.