One pound is exactly 0.45359237 kilograms, so to convert pounds to kilograms multiply by 0.45359237, and to convert kilograms to pounds divide by it. 70 kg is 154.32 lb, 1 kg is 2.2046 lb, and 1 ounce is 28.3495 grams.
It is unit math only. For BMI context after a conversion, see the BMI calculator. For formula based size targets, try the ideal weight calculator.
How the formula works
Each unit maps to kilograms: kg = 1, lb = 0.45359237, g = 0.001, oz = 0.028349523125. Multiply the input by its from factor to reach kilograms, then divide by the to factor.
Worked example
Value 70, from kg, to lb. Kilograms stay 70. Divide by 0.45359237 to get pounds: 70 / 0.45359237 ≈ 154.3236 lb.
| Input | Value |
|---|---|
| Value | 70 |
| From | kg |
| To | lb |
| kg per lb | 0.45359237 |
| Converted | about 154.3236 lb |
kg to lb chart and lb to kg chart
| kg | lb |
|---|---|
| 1 | 2.2046 |
| 50 | 110.2 |
| 60 | 132.3 |
| 70 | 154.3 |
| 80 | 176.4 |
| 90 | 198.4 |
| 100 | 220.5 |
| lb | kg |
|---|---|
| 1 | 0.4536 |
| 100 | 45.4 |
| 120 | 54.4 |
| 150 | 68.0 |
| 180 | 81.6 |
| 200 | 90.7 |
How to use the fields
- Value is the numeric amount in the source unit.
- From selects kg, lb, g, or oz.
- To selects the destination unit.
Why the pound factor matters
Rounded shortcuts such as “multiply by 2.2” drift on purpose built lab sheets. Using 0.45359237 keeps kg and lb aligned with the international avoirdupois pound definition this tool ships with.
Reverse the default: 154.3236 lb × 0.45359237 should return essentially 70 kg aside from display rounding.
The quick ×2.2 rule gives 154.0 lb for 70 kg, which is 0.32 lb short of the exact 154.32 lb.
Common mistakes
- Swapping from and to units
- Using 2.2 as if it were exact
- Mixing fluid ounces with mass ounces
- Reading conversion as a health judgment
Grams and ounces
Food labels often jump between g and oz. Convert through the same kilogram bridge so you do not invent a second factor set. Small package sizes benefit from more decimal places than body weight displays.
When a recipe lists ounces and your scale shows grams, convert once, then weigh. Re-converting every ingredient by a rounded mental factor stacks error.
| From | To |
|---|---|
| 1 oz | 28.3495 g |
| 100 g | 3.5274 oz |
| 1 kg | 35.2740 oz |
| 1 lb | 16 oz |
| 500 g | 1.1023 lb |
Health pages stay separate
Converted weight feeds BMI or energy tools only after you choose the correct unit those tools expect. Do not treat 154.3236 lb as a dietary plan. Pair conversions with the TDEE calculator or protein calculator only when you intentionally move into nutrition math. For body size formulas that take kilograms, see the body surface area calculator.
Rounding for forms
Passports, shipping labels, and clinic forms may demand whole pounds or one decimal. Keep the exact conversion in notes, then round once for the form. State the rounding rule beside the submitted number.
Shipping dim and mass rules are outside this converter; here you only change units. For carrier billable weight, use the DIM weight calculator.
Comparing two conversion paths
Keep one unrounded kilogram value when you chain conversions.
Limitations
No troy ounces, no stones, and no planet gravity “weight” physics. The calculator converts mass style units with the fixed factor table above.