Convert length, weight and temperature units all in one place.
The length and weight conversions in this tool actually run as a two-step calculation under the hood: first the source value is converted into a common base unit (meters for length, kilograms for weight), then the base value is converted into the target unit. Converting kilometers to feet, for example, first multiplies by 1000 to get meters (the base unit), then divides by the feet-to-meters factor of 0.3048 to get feet. The advantage of this design is that each unit only needs one factor relative to the base unit, so any pair of units can convert through each other without a dedicated formula for every combination. The trade-off is two floating-point operations instead of one, each introducing a tiny rounding error — negligible for everyday use, but worth knowing if you need engineering-grade precision.
Temperature isn't a simple proportional relationship the way length or weight is. Celsius, Fahrenheit, and Kelvin are linear but *not* proportional to each other — they involve addition and subtraction, not just a multiplier. 0°C, for instance, doesn't convert to 0°F but to 32°F, because the two scales define "zero" differently. This tool first converts any input value to Celsius as an intermediate step, then from Celsius to the target unit: Fahrenheit uses "Celsius × 9/5 + 32," Kelvin uses "Celsius + 273.15." That's why temperature is handled by an entirely separate code path from length and weight in this tool.
Results here are rounded to 4 decimal places, which is more than enough for everyday use — converting a recipe's weight, checking your height in feet, or reading a temperature while traveling. If you're doing engineering work or need more significant figures, it's worth recalculating by hand with the raw conversion factors or using a dedicated scientific calculator, since the 4-decimal rounding introduces a tiny error at the final step that's invisible day-to-day but may not be tight enough for high-precision needs.
Using length conversion as an example: 1 mile has a base-unit (meters) factor of 1609.34, and 1 kilometer has a base-unit factor of 1000. The conversion runs as: first convert 1 mile to the base unit, meters → 1 × 1609.34 = 1609.34 meters; then divide 1609.34 meters by the kilometer factor of 1000 → 1609.34 ÷ 1000 = 1.6093 km (rounded to 4 decimal places). That's exactly the two-step calculation this tool runs internally — you can verify any length or weight conversion by hand using the same two steps.
Results are always rounded to 4 decimal places for display. If you kept more decimal places in your own calculation, the last digit or two may differ slightly — that's normal rounding behavior and doesn't affect accuracy for everyday use.
No. Every conversion formula and factor is hard-coded in the page's JavaScript, and all calculations run entirely in your browser. There are no network requests — the numbers you enter never leave your device.
No. Length and weight are simple proportional conversions (multiply or divide by a factor). Temperature, because Celsius, Fahrenheit, and Kelvin each define "zero" differently, must first be normalized to Celsius as an intermediate unit before converting to the target — the formulas involve addition and subtraction, not pure multiplication.
Not currently — this tool supports only Length, Weight, and Temperature, which is the complete list shown in the category dropdown. Any future category additions would be announced separately.
Yes, the value field is a standard number input that accepts positive numbers, negative numbers, and decimals (negative values are especially common for temperature, e.g. sub-zero Celsius readings). Non-numeric input is treated as 0 for the calculation.