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Megohms to Ohms Converter

Convert Megohms (MΩ) to Ohms (Ω) instantly. Features a visual 4-band resistor color code generator for calculated values and E12 standard value lookups.

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Category Electronics
MΩ

Enter value in Megohms. Supports standard values (e.g., 4.7).

Resistance in Ohms (Ω)
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Resistance in Kilohms (kΩ)
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About

High resistance values in electronic circuits, particularly in insulation testing, high-impedance operational amplifier inputs, and voltage dividers, are frequently denoted in Megohms. A Megohm represents one million Ohms. While the conversion involves a simple factor of one million, reading errors often occur when translating these abstract figures into physical components or performing precision calculations for series-parallel circuits. Misplacing a decimal point by six orders of magnitude leads to catastrophic circuit failure, either through open-circuit behavior where current cannot flow or thermal runaway if resistance is underestimated.

This tool serves two critical engineering functions. First, it performs the numerical conversion between Megohms and base Ohms with high precision, handling floating-point variations. Second, it bridges the gap between schematic diagrams and physical hardware by generating the corresponding 4-band resistor color code. This visual verification assists hobbyists and technicians in selecting the correct component from a storage bin, reducing the likelihood of soldering the wrong part. The calculator also identifies the nearest standard E12 resistor series value, ensuring that theoretical calculations align with commercially available hardware components.

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Formulas

The relationship between Megohms and Ohms is linear and based on the SI prefix "mega", which denotes a factor of 106. The conversion formula is straightforward but requires strict attention to scientific notation when values are very small or very large.

RΩ = RMΩ × 1,000,000

Alternatively, expressed in scientific notation for ease of calculation in physics applications:

RΩ = RMΩ × 106

To reverse the calculation (Ohms to Megohms):

RMΩ = RΩ1,000,000

Reference Data

Resistance (MΩ)Resistance (Ω)Standard (E12)Color Code (4-Band)
0.0011,000YesBrown, Black, Red
0.0110,000YesBrown, Black, Orange
0.1100,000YesBrown, Black, Yellow
0.47470,000YesYellow, Violet, Yellow
11,000,000YesBrown, Black, Green
2.22,200,000YesRed, Red, Green
4.74,700,000YesYellow, Violet, Green
1010,000,000YesBrown, Black, Blue
2222,000,000YesRed, Red, Blue
100100,000,000YesBrown, Black, Violet

Frequently Asked Questions

Resistor color codes are typically used for standard integer values with specific multipliers. If you enter a non-standard specific decimal, such as 1.2345 Megohms, it does not correspond to a physical 4-band resistor configuration. The tool displays color codes for values that can be physically represented (Standard E-Series or simple integers). For precise non-standard resistance, manufacturers typically use numeric printing (SMD codes) or 5-band/6-band codes for high precision (1% or less tolerance).
The E12 series is a standard set of preferred numbers for electronic components used by the IEC 60063 standard. It dictates that within every decade (e.g., 10 to 100), there are 12 standard steps (10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, 82). Components like resistors are manufactured to these values to limit inventory while covering the entire range within a 10% tolerance.
Most digital multimeters (DMMs) can measure resistance up to 20 MΩ or 40 MΩ. However, for very high resistance (Gigohms) typically found in insulation testing, a standard multimeter lacks the internal voltage source required to drive measurable current through the resistance. In such cases, a specialized device called a Megohmmeter or "Megger" is required.
The gap separates the value bands from the tolerance band. On a 4-band resistor, the first three bands (Digit, Digit, Multiplier) are grouped closer together, while the fourth band (Tolerance, usually Gold or Silver) is spaced slightly apart to indicate the reading direction (left to right).
High-value resistors are often more susceptible to noise and leakage currents caused by humidity and surface contamination. While the temperature coefficient (ppm/°C) depends on the material (carbon film vs. metal film), environmental factors often cause greater drift in Megohm-range resistors than thermal expansion alone.