Weight Converter

This weight hub converts among kilograms (kg), pounds (lbs), ounces (oz), and grams (g). It is the canonical broad page for these four mass and everyday weight units, so other narrow pages can point here when a reader needs the bigger map. the calculator accepts a nonnegative value, a source unit, and a target unit. It returns the selected conversion as the primary result and lists the remaining supported units, excluding the source and target, as reference rows.

The page is intentionally about one physical quantity: mass in the everyday sense of weight labels used on food, fitness logs, shipping forms, product specifications, and recipes. It does not convert volume to weight, because that requires density. It does not convert force units such as newtons, because force depends on acceleration. It also does not convert stones, tons, carats, or grains in this calculator; use a focused page when those units are needed.

Unit family and definitions

The kilogram is the SI base unit for mass. The gram is a decimal submultiple of the kilogram, with 1 gram equal to 0.001 kilogram. The international avoirdupois definitions make one pound exactly 0.45359237 kg and one ounce exactly 0.028349523125 kg.

Kilograms provide the bridge. Multiply a source value by its factor to get kilograms, then divide by the target factor. This supports kg to lb, lb to g, oz to kg, and g to oz without separate formulas for every pair.

Coverage table

The factors are direct and proportional, so doubling the input doubles every output. The displayed answer uses up to six decimals, which keeps everyday results readable while preserving useful detail for recipes and parcel estimates.

Formula used by the calculator

Let the source unit factor and target unit factor both be measured in kilograms:

$\text{kilograms} = \text{value} \times \text{source factor}$

$\text{converted weight} = \frac{\text{kilograms}}{\text{target factor}}$

For grams, the factor is exactly 0.001 kg. The pound and ounce factors are also exact, and their ratio preserves the exact 16-to-1 relationship.

Worked example matching the calculation

Choose Value = 70, From = kilograms, and To = pounds. The source factor for kilograms is 1, so the base value is:

$70 \times 1 = 70\ \text{kg}$

The target factor for pounds is 0.45359237. The result is:

$\frac{70}{0.45359237} = 154.3235835\ldots\ \text{lbs}$

Because the source is kilograms and the target is pounds, the reference rows exclude both units. The calculator lists ounces and grams: 70 kg divided by 0.028349523125 gives 2,469.177336… oz, and 70 kg divided by 0.001 gives 70,000 g.

Picking the right sub-converter

Use this hub when you want to compare several weight units at once. For a shareable single path, use pounds to kilograms when reading U.S. body weights in a metric setting, ounces to grams when adapting a recipe or nutrition label, pounds to grams when a bulk food or shipping value needs metric detail, and ounces to pounds when parcel or ingredient weights are listed in small imperial units. Pet owners can use the dog weight calculator when the question is growth or breed context rather than pure unit conversion.

If the starting value is a fluid measure, stop before converting. A cup of water and a cup of flour have different masses, so a volume-to-weight page must know density or ingredient assumptions. For liquid capacity, use the volume converter instead. For a multi-category unit table that includes mass alongside length, area, volume, time, and speed, use the measurement converter.

Domains and pitfalls

Cooking and baking often need grams for repeatability, while older recipes and U.S. packaging may list ounces or pounds. Fitness and health logs commonly mix kilograms and pounds, especially when comparing international charts. Shipping estimates need attention to carrier rounding: a parcel scale reading may be rounded up to a billable bracket. Product data sheets may list both metric and customary weights, but the rounded numbers might not convert perfectly back and forth.

Two pitfalls cause most mistakes. First, people sometimes enter a negative value for a loss or difference. the calculator is built for nonnegative quantities, so express a loss as a positive amount and describe the direction separately. Second, people confuse weight with volume. If a recipe says 8 fluid ounces, that is a volume, not necessarily 8 ounces by weight. Use the unit printed on the source carefully.

Sources

• BIPM, Measurement units — SI unit system context, including the kilogram as the mass base unit.
• NIST, SI Units — U.S. reference for SI units and metric usage.
• NIST, Special Publication 811 — guidance on SI notation, unit symbols, and conversion presentation.