Electric Resistance converter

The ohm (Ω) is the base unit of electric resistance, and the other units here scale it by clean powers of ten: a kiloohm (kΩ) is 1,000 Ω, a megaohm (MΩ) is 1,000,000 Ω, a gigaohm (GΩ) is a billion ohms, while a milliohm (mΩ) is 0.001 Ω and a microohm (µΩ) is a millionth of an ohm. The abohm, from the CGS electromagnetic system, is a vanishingly small 1e-9 Ω, and the statohm, from the CGS electrostatic system, is an enormous 898,755,178,736.8176 Ω — both legacy units that surface occasionally in older physics references. The volt per ampere (V/A) is simply Ohm's law written as a unit: by definition it equals exactly one ohm.

The featured conversion on this page turns kiloohm into ohm with Ω = kΩ × 1,000, and the reverse direction multiplies by 0.001.

A 4.7 kΩ resistor, a very common value in electronics, converts to 4.7 × 1,000 = 4,700 Ω. A precision 2.2 MΩ resistor equals 2,200 kΩ when you need the intermediate unit, and a 15 mΩ current-sense shunt converts to 0.015 Ω — a number small enough that engineers almost always keep it in milliohms to avoid writing long strings of zeros.

Resistance spans an unusually wide practical range. Milliohm and microohm values describe the resistance of shunt resistors, connector contacts, and PCB copper traces, where even a few milliohms of unwanted resistance can waste power as heat in a high-current circuit. Ordinary resistors in consumer electronics live in the ohm-to-megaohm range, and insulation-resistance testing on cables or motor windings is reported in megaohms or gigaohms, because a healthy insulator should resist current almost completely.

A common slip is misreading the ohm symbol (Ω) for a zero or the letter O in hand-written notes or low-resolution scans, which can turn "4.7 kΩ" into something unrecognizable. Another is forgetting that kiloohm and megaohm differ by a factor of 1,000, not 100, when mentally converting between data-sheet values — a slip that matters a lot when sizing a pull-up resistor or interpreting an insulation-resistance test result.

Resistance tolerance is also worth keeping in mind once you've done the conversion math. A resistor marked 4.7 kΩ with a 5% tolerance could genuinely measure anywhere between about 4,465 Ω and 4,935 Ω straight off the shelf, so a perfectly correct unit conversion can still disagree with a real multimeter reading simply because the component itself was never meant to be exact. Treat a converted value as the nominal target, not a guarantee of what any single physical resistor will measure.

Resistance also isn't fixed for a given component the way its printed value might suggest, because most materials' resistance changes with temperature. Copper wire, for instance, gets noticeably more resistive as it heats up, which is why motor windings and long cable runs carrying heavy current are rated with their resistance checked under realistic operating temperatures rather than at a cool bench reading, and why insulation and grounding tests are often specified at a standard reference temperature so results from different days can be fairly compared.