A 12-inch shelf is 30.48 cm
Length conversions use metres as the base. One inch is exactly 0.0254 m, so 12 × 0.0254 ÷ 0.01 = 30.48 cm. Divide centimetres by 2.54 to get inches. Feet, yards and miles use international definitions.
MEASUREMENT TOOLS
Length, mass and temperature converter
Convert inches and centimetres, pounds and grams, Celsius and Fahrenheit, and compare equivalent values across units.
Free · No sign-up · Processed on your deviceUNIT BENCH
Convert a value, understand the units
Absolute input limit: one trillion. Displayed results are rounded to 10 significant figures.
CONVERSION RESULT
Your conversion
The same value in other units
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MEASUREMENT NOTES
Start with the meaning of the unit
A 2-pound pack is about 907.185 g
The avoirdupois pound uses 1 lb = 0.45359237 kg. Two pounds are 907.18474 g, and one pound contains 16 ounces. Here oz is a unit of mass. It is different from fluid ounces for volume and troy ounces for precious metals.
20 °C is 68 °F
Temperature scales have different zero points as well as different step sizes. Use °F = °C × 1.8 + 32, so 20 × 1.8 + 32 = 68 °F. A temperature difference of 20 °C is not a difference of 68 °F. This tool converts temperatures, not temperature intervals.
Definition references: NIST · SI Units — Length, NIST SP 811 · Conversion factors.
Why are results rounded when the definitions are exact?
Browsers use floating-point arithmetic, and division can produce repeating decimals. Results are displayed to 10 significant figures. This is not a measurement accuracy claim: converting a two-digit measurement does not add real precision.
Can I enter a negative value?
Length and mass preserve the mathematical sign; this does not imply a physical object has negative size or mass. Temperatures below absolute zero — 0 K, −273.15 °C or −459.67 °F — are rejected.
Why are cups, land-area units and currency absent?
This tool focuses on length, mass and temperature. Cups measure volume and vary by country; exchange rates change over time. Keeping the scope explicit avoids mixing quantities that only look similar.
Are input values saved?
Calculations run in the open browser. The tool does not send inputs to a service server or save them. Refreshing restores the example values. Copy any results you want to keep.