Centimeter to Decimeter Converter

The centimeter (symbol: cm) is a unit of length equal to exactly one-hundredth of a meter (1/100 m or 0.01 m). It's also equal to exactly 10 millimeters.

The centimeter is part of the International System of Units (SI) and uses the metric prefix "centi-" meaning one-hundredth (from Latin centum, "hundred").

Mathematical Relationships

1 centimeter equals:

• 10 millimeters (mm)
• 0.01 meters (m)
• 0.00001 kilometers (km)
• 0.393701 inches (in)
• 0.0328084 feet (ft)

Key conversion:

• 1 inch = 2.54 cm exactly (this is the official international definition established in 1959)

Why Centimeters?

While the meter is the official SI base unit for length, centimeters are more practical for everyday measurements:

Too small for meters, too large for millimeters: A person who is 1.75 meters tall is more commonly described as 175 centimeters in metric countries. Writing "1.75 m" requires decimals; "175 cm" uses whole numbers.

Human-scale convenience: Most objects people interact with daily—clothing, screens, body measurements, food items—fall naturally into the 1-100 cm range.

Avoids decimal confusion: "15.2 cm" is clearer than "0.152 m" for most people.

French Revolution and the Birth of the Metric System

1790s: Revolutionary Innovation: The centimeter was born from the French Revolution's ambition to create a rational, universal measurement system based on nature and decimal mathematics.

The Meter Foundation: In 1791, the French Academy of Sciences defined the meter as one ten-millionth (1/10,000,000) of the distance from the equator to the North Pole along the meridian passing through Paris. The centimeter automatically followed as 1/100 of this meter.

Latin Roots: The prefix "centi-" derives from the Latin centum (hundred), making "centimeter" literally "hundredth of a meter."

1795 Official Adoption: France officially adopted the metric system on April 7, 1795, including the centimeter as a standard subdivision of the meter.

CGS System: The Centimeter's Scientific Era

1874: The Centimeter-Gram-Second System: British scientists James Clerk Maxwell and William Thomson (Lord Kelvin) promoted the CGS system, which used:

• Centimeter for length (instead of meter)
• Gram for mass (instead of kilogram)
• Second for time

Scientific Dominance: The CGS system became the preferred standard for physics and chemistry throughout the late 19th and early 20th centuries. Many scientific formulas and units were developed using centimeters.

Legacy Units: Several units still reflect the CGS heritage:

• Poise (viscosity): measured in gram/(centimeter·second)
• Erg (energy): gram·centimeter²/second²
• Gauss (magnetic field): CGS unit for magnetic flux density

Transition to SI and the Modern Era

1960: The SI System: The International System of Units (SI) was officially established, promoting the meter-kilogram-second (MKS) system instead of CGS.

Centimeter's Continued Relevance: Despite the official SI preference for meters, centimeters remained dominant for everyday measurements because:

• They're more practical for human-scale objects
• They avoid decimals for most common measurements
• They're familiar and intuitive

Global Adoption: Today, 195 of 198 countries use the metric system, with centimeters as the standard for body height, clothing, and everyday measurements. Only the United States, Myanmar, and Liberia officially use non-metric systems.

Medical and Healthcare

Growth Charts: Children's height is tracked in centimeters from birth:

• Pediatricians plot growth on percentile charts
• Birth length recorded in cm (typically 45-55 cm)
• Annual height measurements track development

Medical Measurements:

• Wound size: "3 cm laceration"
• Tumor diameter: measured in cm for staging
• Organ size: "enlarged liver extending 4 cm below rib cage"
• Dilation during childbirth: measured in cm (0-10 cm)

Medical Equipment:

• Blood pressure cuff width: 12-13 cm for adults
• Surgical incision length: documented in cm
• Catheter diameter: measured in mm, length in cm

Education and School Supplies

Rulers and Measuring Tools: Most rulers worldwide show centimeters:

• Standard ruler: 15 cm or 30 cm length
• Meter stick: 100 cm with cm markings
• Tape measures: marked in cm (and meters)

Paper Sizes (International ISO 216 Standard):

• A4 paper: 21 × 29.7 cm (most common worldwide)
• A5 paper: 14.8 × 21 cm (half of A4)
• A3 paper: 29.7 × 42 cm (double A4)
• Letter size (US): 21.6 × 27.9 cm (8.5 × 11 inches)

School Supplies:

• Pencil length: 19 cm (new)
• Notebook width: 15-21 cm
• Eraser length: 4-6 cm

Construction and Home Improvement

Tile Sizes: Floor and wall tiles measured in cm:

• Small tiles: 10×10 cm
• Medium tiles: 30×30 cm
• Large format tiles: 60×60 cm or 80×80 cm
• Subway tiles: 7.5×15 cm

Furniture Dimensions:

• Coffee table height: 40-50 cm
• Dining table height: 75 cm (standard)
• Chair seat height: 45-50 cm
• Sofa seat depth: 50-60 cm

Door Measurements:

• Standard interior door width: 80-90 cm
• Standard door height: 200-210 cm
• Door thickness: 3.5-4.5 cm

Art, Design, and Photography

Photo Print Sizes:

• 10×15 cm (4×6 inches) - standard print
• 13×18 cm (5×7 inches)
• 20×25 cm (8×10 inches)
• 30×40 cm (12×16 inches)

Canvas and Frame Sizes: Art supply stores sell in metric:

• Small canvas: 20×25 cm
• Medium canvas: 30×40 cm
• Large canvas: 50×70 cm

Drawing and Design:

• Technical drawings: dimensioned in cm or mm
• Graph paper: 0.5 cm or 1 cm grids
• Architectural scales: often use 1:50 or 1:100 (cm-based)

Sports and Recreation

Swimming Pool Depth: Measured in cm or meters:

• Shallow end: 90-120 cm
• Deep end: 180-300 cm
• Competition pool depth: minimum 200 cm

Bicycle Frame Sizes: Road bikes measured in cm:

• Small frame: 48-52 cm
• Medium frame: 54-56 cm
• Large frame: 58-62 cm

Sports Equipment:

• Tennis ball diameter: 6.5-6.7 cm
• Golf ball diameter: 4.3 cm
• Basketball diameter: 24 cm