Resistance Converter

Type a resistance value and unit, pick the target unit, and read off the converted figure. Ohms, kilohms, and megohms are the three stops you'll hit on most schematics, and resistor values often jump three orders of magnitude between stages of a circuit.

The converter accepts both decimal and scientific notation. A 4M7 marking on a resistor body means 4.7 megohms — type 4.7M and you'll get 4,700,000 ohms.

For color-band decoding (5-band or 6-band resistors), you'll want a separate decoder. This tool only handles unit conversion of values you already have.

The relationship is simple decimal scaling: 1 MΩ = 1,000 kΩ = 1,000,000 Ω = 1,000,000,000 mΩ. Practical resistor values live in three regions. Sub-ohm to a few ohms for current sense, shunts, and high-power dissipation. Ones to thousands of ohms for circuit biasing, current limiting, and signal-level work. Tens of kilohms to megohms for high-impedance feedback paths in op-amps and CMOS gate biasing where you want negligible loading.

Worked example: an LED driver needs to limit 20mA across a 5V supply with a 2V LED forward voltage. Ohm's law: R = (5 - 2) / 0.02 = 150 Ω. Your distributor's stock list shows the value as 0.15K. Run the converter to confirm 0.15 kΩ = 150 Ω. Now check that an E12-series resistor is available — 150 Ω is a standard E12 value, so the BOM goes through clean. If your math returned 137 Ω, you'd round to 150 Ω anyway because 137 isn't a stocked value and the LED won't notice the 8% difference.

What to watch for: tolerance and temperature coefficient eat any precision the converter offers. A 1.000 kΩ converted from 1000 Ω stays 1.000 kΩ — but the actual resistor sitting on your board is 1% or 5% off that nominal value. For metrology or precision instrumentation, you need 0.1% or 0.01% tolerance parts and probably a calibrated reference; the converter handles the math but not the reality of physical components.

Quick reference for what value range fits each application: 0.001-1Ω for current shunts. 1-100Ω for current limiting (LEDs, drivers). 100-10kΩ for biasing transistors and MOSFETs. 10k-1MΩ for op-amp feedback networks and pull-ups. Above 1MΩ for high-impedance sense lines and CMOS gate biasing where minimal loading matters. Picking outside the typical range usually means there's a circuit design reason worth checking — designers don't reach for a 22MΩ resistor casually.