How many megameters are in a centimeter?

One centimeter is exactly 0.00000001 megameters, or 1 × 10⁻⁸ Mm.

A megameter is 1,000,000 meters, or 1,000 kilometers. Its symbol is Mm, with a capital M. It is not the same as a millimeter, whose symbol is mm.

What is the formula for converting cm to Mm?

Multiply the value in centimeters by 10⁻⁸, or divide by 100,000,000. For example, 2.6 cm is 0.000000026 Mm. You can show the conversion in two steps: divide by 100 to get meters, then divide by 1,000,000 to get megameters.

How many centimeters are in one megameter?

One megameter is exactly 100,000,000 centimeters. Choose Megameters → centimeters to convert in this direction.

Why does a small conversion show zero in decimal notation?

The result may be too small to appear at the selected number of decimal places. For example, 2.6 cm equals 0.000000026 Mm, which is displayed as 0.000000 Mm to six decimal places. It is not zero; scientific notation shows it as 2.600000 × 10⁻⁸ Mm.

semkuLength converter

Convert centimeters to megameters

Convert between centimeters (cm) and megameters (Mm). See both decimal and scientific notation, with the units shown in each step.

Measurement Input unit: centimeters (cm) Enter one measurement, such as 2.6 or 1/3. You can add the unit required by the selected direction.

Conversion direction

Centimeters → megameters Megameters → centimeters

Any unit you enter must match the selected direction. Changing direction keeps the input text.

Decimal places This setting controls decimal places in the decimal result and in the scientific-notation coefficient. It does not set the number of significant figures.

Mm means megameter; mm means millimeter. The capital M changes the unit. Use a decimal point or comma: 2.6 and 2,6 mean the same measurement. Fractions such as 1/3 and mixed numbers such as 2 1/2 are also supported. Thousands separators are not supported. Enter one thousand as 1000; 1,000 and 1.000 are read as one.

Result

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Enter a measurement to see the result.

The conversion factor is exact. The converter does not add precision to the measurement you enter. Scientific notation writes a number as a coefficient multiplied by a power of ten. The two result formats may be rounded differently.

The copy includes your input, the exact factor, the steps and both result formats. Copied text may remain on your clipboard.

Worked example

2.6 cm = 0.000000026 Mm = 2.6 × 10⁻⁸ Mm 2.6 cm × (1 m / 100 cm) × (1 Mm / 1,000,000 m) = 0.000000026 Mm With six decimal places, the decimal result is shown as 0.000000 Mm. The scientific notation keeps the non-zero value visible.

Conversion rules and supported formats

The SI prefix centi means one hundredth, and mega means one million. One centimeter is 0.01 meters and one megameter is 1000000 meters. Dividing these factors gives exactly 0.00000001 megameters per centimeter, or 10⁻⁸ Mm per cm. In the other direction, multiply megameters by 100000000 to get centimeters.

NIST: metric (SI) prefixes

For centimeters to megameters, the steps are: measurement in cm × (1 m / 100 cm) × (1 Mm / 1000000 m). The cm units cancel in the first step, then the m units cancel in the second. The remaining unit is Mm. For the reverse direction, use (1000000 m / 1 Mm), then (100 cm / 1 m).

Calculations use the full input value, including fractions, without intermediate rounding. Decimal notation and scientific notation are each produced from the unrounded converted value. Only the displayed numbers are rounded.

The decimal-places setting controls the digits after the decimal point in the decimal result and in the scientific-notation coefficient. It is not a significant-figures setting. Values halfway between two display choices are rounded upward. For example, 2.5 is displayed as 3 with no decimal places. Trailing zeros are kept.

For a non-zero result, the scientific-notation coefficient is at least 1 and less than 10. If rounding would make it 10, the coefficient is changed to 1 and the exponent is increased by one. Zero is shown with a coefficient of 0 and an exponent of 0. A small positive value may appear as zero in decimal notation; the scientific notation remains visible.

No rounding needed applies to the particular displayed number. A decimal result can need no rounding while its scientific notation is rounded. Neither label verifies the accuracy of the original measurement. The ≈ symbol marks an approximate result.

Enter one non-negative measurement. Whole numbers, decimals, fractions such as 1/3, and mixed numbers such as 2 1/2 or 2-1/2 are supported. The supported fraction characters are ½, ⅓, ⅔, ¼, ¾, ⅕, ⅖, ⅗, ⅘, ⅙, ⅚, ⅛, ⅜, ⅝ and ⅞. They can be used alone or after a whole number, as in 2½.

Use a decimal point or comma, with no thousands separators. The whole-number part can contain up to 12 digits. Scientific notation is an output format, not an input format: enter 0.000000026 rather than 2.6e-8.

Unit symbols are optional and case-sensitive. Use cm for centimeter inputs and Mm for megameter inputs. The symbols m, mm and km mean meters, millimeters and kilometers; they do not match either input direction on this page. Adding a unit does not change the selected direction. Lists, sets of dimensions and mixed feet-and-inches measurements are not supported.

Conversion rules v1 · 14 September 2026

Frequently asked questions

How many megameters are in a centimeter?: One centimeter is exactly 0.00000001 megameters, or 1 × 10⁻⁸ Mm.
What is a megameter?: A megameter is 1,000,000 meters, or 1,000 kilometers. Its symbol is Mm, with a capital M. It is not the same as a millimeter, whose symbol is mm.
What is the formula for converting cm to Mm?: Multiply the value in centimeters by 10⁻⁸, or divide by 100,000,000. For example, 2.6 cm is 0.000000026 Mm. You can show the conversion in two steps: divide by 100 to get meters, then divide by 1,000,000 to get megameters.
How many centimeters are in one megameter?: One megameter is exactly 100,000,000 centimeters. Choose Megameters → centimeters to convert in this direction.
Why does a small conversion show zero in decimal notation?: The result may be too small to appear at the selected number of decimal places. For example, 2.6 cm equals 0.000000026 Mm, which is displayed as 0.000000 Mm to six decimal places. It is not zero; scientific notation shows it as 2.600000 × 10⁻⁸ Mm.

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