Electrical Resistance Converter (Ω, kΩ, MΩ)
Convert electrical resistance between ohms, kilohms, and megohms instantly, with a conversion table and common equivalents.
Electrical Resistance Converter (Ω, kΩ, MΩ)
Calculator
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Formula: Target = Value x (FromFactor / ToFactor) | Conductance (S) = 1 / Resistance (Ohm)
Worked example — 4.7 kOhm = 4,700 Ohm = 0.0047 MOhm
Formula
Target = Value x (FromFactor / ToFactor) | Conductance (S) = 1 / Resistance (Ohm)
Resistance unit conversion uses metric prefixes. Each unit differs by a factor of 1000 from its neighbor. The base unit is the ohm. Microohms are 10 to the negative 6 ohms, milliohms are 10 to the negative 3, kilohms are 10 to the 3, megohms are 10 to the 6, and gigohms are 10 to the 9. Conductance in siemens is the inverse of resistance in ohms.
Worked Examples
Example 1: Resistor Color Code Conversion
Problem:A resistor has bands showing 4.7 kilohms. Express this in ohms and megohms.
Solution:4.7 kOhm x 1000 = 4700 Ohm 4700 Ohm / 1,000,000 = 0.0047 MOhm Conductance = 1 / 4700 = 0.000213 S = 0.213 mS
Result:4.7 kOhm = 4,700 Ohm = 0.0047 MOhm
Example 2: PCB Trace Resistance
Problem:A PCB trace has a resistance of 15 milliohms. Convert to ohms and microohms.
Solution:15 mOhm x 0.001 = 0.015 Ohm 15 mOhm x 1000 = 15,000 uOhm
Result:15 mOhm = 0.015 Ohm = 15,000 uOhm
Frequently Asked Questions
What is electrical resistance and what unit is it measured in?
Electrical resistance is the opposition to the flow of electric current through a conductor. It is measured in ohms, symbolized by the Greek letter omega. The ohm is defined as the resistance that allows one ampere of current to flow when one volt is applied across the conductor. Resistance depends on the material, length, cross-sectional area, and temperature of the conductor.
How do I convert between different resistance units?
Resistance units follow standard metric prefixes. One kilohm equals 1000 ohms, one megohm equals 1,000,000 ohms, and one milliohm equals 0.001 ohms. To convert, multiply or divide by powers of 1000. For example, to convert 4700 ohms to kilohms, divide by 1000 to get 4.7 kilohms. This converter handles all common resistance unit conversions automatically.
What is the relationship between resistance and conductance?
Conductance is the reciprocal of resistance. It measures how easily current flows through a conductor, while resistance measures how much current is opposed. Conductance is measured in siemens (S), where 1 siemens equals 1 divided by 1 ohm. A 100 ohm resistor has a conductance of 0.01 siemens or 10 millisiemens. This inverse relationship is fundamental in circuit analysis.
What are common resistance values used in electronics?
Standard resistor values follow the E-series system. The most common series is E12, which includes values like 10, 12, 15, 18, 22, 27, 33, 39, 47, 56, 68, and 82 ohms, and their multiples. Typical applications use resistors from a few ohms (power circuits) to several megohms (sensor circuits). Pull-up resistors commonly range from 1 kilohm to 10 kilohms, and voltage dividers use various combinations.
How do length, cross-section and resistivity determine resistance?
Resistance equals resistivity multiplied by conductor length and divided by cross-sectional area. Resistivity is a material property measured in ohm-metres; annealed copper is about 1.68 x 10^-8 ohm-metres at 20 degrees C, and aluminium is substantially higher. Doubling the length doubles resistance, while doubling the cross-sectional area halves it. This relationship is why long cable runs need thicker conductors to hold voltage drop within limits, and why sense leads are kept short.
How does temperature change a resistor's value?
Metals have a positive temperature coefficient, so resistance rises as they heat. Resistance at temperature T is approximately the reference resistance multiplied by one plus the coefficient times the temperature rise. Copper's coefficient is about 0.00393 per degree C, so a 40 degree rise increases a copper winding's resistance by roughly 16 percent, which is the basis of winding-temperature measurement in motors. Precision metal-film resistors are specified in parts per million per degree C to keep this drift negligible.
What is the difference between resistance and impedance?
Resistance opposes current and dissipates energy as heat, and it is the same at any frequency. Impedance is the more general opposition in an AC circuit, combining resistance with reactance from capacitance and inductance, and it is written as a complex quantity with a magnitude and a phase angle. Both are expressed in ohms. At direct current an inductor's reactance falls to zero, so a purely resistive-inductive branch settles to its plain DC resistance, while a capacitor's reactance grows without limit and that branch instead behaves as an open circuit.
Why are insulation measurements expressed in megohms and gigohms?
Insulation is meant to block current almost entirely, so a healthy sample measures in the millions or billions of ohms rather than in the ohms typical of a conductor. Insulation resistance testers apply a high DC test voltage and measure the tiny leakage current that results, reporting the ratio in megohms. A falling trend over successive tests indicates moisture ingress, contamination or thermal ageing, which is why the change over time matters as much as the absolute reading.
How do resistors combine in series and parallel?
In series, resistance simply adds, so a 4.7 kilohm and a 10 kilohm resistor in series give 14.7 kilohms. In parallel, the reciprocals add: one over the total equals the sum of the reciprocals of each branch. Two identical 10 kilohm resistors in parallel therefore give 5 kilohms, and the parallel total is always lower than the smallest branch. Mixed networks are solved by collapsing the innermost series or parallel groups first and working outward.
What does a resistor's tolerance band mean for a converted value?
Tolerance states the permitted deviation of the actual resistance from the marked nominal value. A 4.7 kilohm resistor with a 5 percent tolerance may measure anywhere between 4.465 and 4.935 kilohms, since 5 percent of 4700 ohms is 235 ohms. Unit conversion is exact, but the underlying component value is not, so quoting a converted result to six figures implies a precision the part does not possess. Match the significant figures you report to the tolerance of the component.
References
Reviewed for accuracy by Manoj Kumar, Mathematics Educator · Editorial policy
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