Pounds and ounces to kilograms
Match the mass unit on your record
For a compound reading in pounds and ounces, convert with kg = (lb + oz ÷ 16) × 0.45359237. For decimal pounds, multiply the single pound value by 0.45359237. Grams are kilograms multiplied by 1000. The converter above supports lb + oz, decimal lb, standalone oz, kg and g.
This is a conversion of an entered mass. It cannot weigh a parcel, detect an incorrect product label or decide which weight a carrier will bill. Start with a known reading and keep its unit and what was weighed in your notes. A product-only mass and the mass of its packed shipping box describe different things even if their units match.
Do not read decimal pounds as pounds and ounces
The decimal part of a pound is a fraction of 16 ounces. Therefore 1.5 lb means 1 lb + 8 oz. It does not mean 1 lb + 5 oz. Likewise, 1.8 lb is not 1 lb + 8 oz.
| Written measurement | Correct mode and entry | Exact calculated mass in kg |
|---|---|---|
| 1 lb and 8 oz | lb + oz: whole pounds 1, remainder 8 | 0.680388555 |
| 1.5 lb | Decimal lb: 1.5 | 0.680388555 |
| 1.8 lb | Decimal lb: 1.8 | 0.816466266 |
| 16 oz | Standalone oz: 16 | 0.45359237 |
For the first row, eight ounces is half a pound, so 1 + 8/16 = 1.5 lb. Multiplying by the pound factor gives 0.680388555 kg, or 680.388555 g. The main kilogram display rounds to 0.6804. For the third row, 0.8 lb represents 12.8 oz, which explains why it is heavier than 1 lb + 8 oz. These examples are synthetic calculations, not measurements of a product.
Enter the compound remainder correctly
In lb + oz mode, pounds must be whole and remaining ounces must be from zero to below 16. If a record says 2 lb + 16 oz, normalize it to 3 lb + 0 oz. The compound field rejects a remainder of 16; the standalone oz mode accepts 16 and returns one pound.
When a scale gives decimal ounces, enter that remainder as a decimal, such as 8.5. There are no fraction fields in this mass converter. A notation such as 8 1/2 oz must be rewritten as 8.5 before entry; typing a slash expression is unsupported. Enter zero explicitly for an absent remainder instead of leaving its field blank.
The standalone oz, lb, kg and g modes all describe one quantity in their selected unit. Selecting kg while entering a number originally in grams changes its interpretation by a factor of 1000. For example, choose g for 250, or choose kg for 0.25; do not enter 250 into kg for a 250 g reading.
Check a metric-to-US result
A second worked example starts at 250 g. That is 0.25 kg. Dividing by 0.45359237 gives approximately 0.5511556555 lb. Multiplying those pounds by 16 gives approximately 8.8184904874 oz, so the compound result displays 0 lb + 8.8185 oz.
For 1 kg, the decimal result is approximately 2.2046226218 lb. Two whole pounds leave approximately 0.2046226218 lb; multiply the remainder by 16 to get approximately 3.2739619496 oz. The compound display is 2 lb + 3.2740 oz. A displayed remainder is not the decimal portion of the pound result.
Remaining ounces round to four decimals using half-up rounding. If they round to 16.0000, the display adds one pound and shows 0.0000 oz. For instance, 453.592369 g is just below one pound but displays 1 lb + 0.0000 oz. That carry avoids a 16-ounce remainder; it does not add mass to the original reading.
Preserve the measurement and the unrounded calculation
The single-unit result rows show four decimal places, with approximate digits up to twelve available under “More digits.” The compound row has its own four-place ounce remainder. Expanded digits describe the conversion calculation; they cannot improve a scale’s original accuracy or resolve an uncertain reading.
Keep the original input for later calculations. Re-entering a rounded kg result can change the next converted answer, and expanded results may exceed the six-decimal input limit. The direction-switch button changes the input format and clears its fields; it does not silently transfer a displayed result into a new measurement.
Use this checklist before relying on the output:
| Check | Action |
|---|---|
| Quantity being weighed | Distinguish product-only, container and fully packed readings |
| Starting unit | Match lb, oz, kg or g to the record |
| Compound notation | Keep whole pounds separate from the ounce remainder |
| Accepted number | Use a decimal point, no unit text, comma or exponent |
| Input range | Nonnegative values through 1,000,000; at most six decimals |
| Missing reading | Measure or confirm it; do not replace a blank with zero |
Whole-pound fields accept only integers, and compound ounces must remain below 16. Zero is valid as an explicitly known input; negatives, malformed decimals and more than six decimal places are rejected.
Know where this conversion stops
The source units are avoirdupois mass units. Fluid ounces measure volume, troy ounces belong to a different mass system, and lbf is a force unit; none is converted by selecting ordinary oz or lb here. Do not infer a liquid’s mass from its volume without separate information.
Use the box-volume tool for a separate geometric dimension calculation. Neither that tool nor this one calculates a shipping charge, allowable payload or a safe lifting limit. A conversion alone cannot establish suitability for moving or storage.
NIST Handbook 44, 2026, Appendix C, checked October 3, 2026, supports 16 avoirdupois ounces per pound in C-7 and the exact 0.45359237 kg pound factor in C-19. The examples and rounding explanations are authored calculations rather than NIST product measurements.
AI-assisted content. Examples are hypothetical; verify the original quantity and unit before using a result.