Inductor Value
Decode inductor color bands and numeric codes. Enter circuit values to calculate the selected electrical quantity.
SMD Inductor Code
Electronics guide · Circuit components and networks
About Inductor Code Converter
Decode a common printed inductor marking into microhenries, millihenries, nanohenries, and a recognized tolerance when possible. The page supports examples such as a numeric multiplier code or a decimal marker like 4R7.
Component calculations simplify a circuit into a formula or ideal model. Real parts have tolerances, ratings, parasitic effects, and wiring details that can change how a circuit behaves, so use the result as a design estimate and compare it with the component datasheet and circuit conditions.
How to Use This Tool
- 1.Enter the exact code printed on the component, including any tolerance letter.
- 2.Calculate and inspect the decoded value and tolerance field.
- 3.Check the package or datasheet because inductor marking systems differ between manufacturers.
Technical Details to Check
1.Match values to the right circuit position
Resistors, capacitors, inductors, and semiconductor pins are not interchangeable inputs. Follow the labels or diagram and check that each value belongs to the correct component or branch.
2.Ideal formulas have assumptions
A calculator may assume a balanced bridge, an ideal switch, a simple RC or RL network, or a specific transistor operating mode. Confirm that the real circuit matches that model before using the result.
3.Datasheet ratings still matter
Calculated values do not establish a safe operating point. Check voltage, current, power, temperature, frequency, and tolerance ratings for every part that will be used.
4.Small errors can move the result
Component tolerances and measurement uncertainty can change timing, bias, resonance, or dissipation. For a design with tight limits, calculate a range using realistic minimum and maximum values.
How the Calculation Works
Numeric codes commonly use two significant digits followed by a power-of-ten multiplier in microhenries; a letter such as R can act as a decimal marker. The helper converts the parsed result to mH, µH, and nH. A suffix can indicate tolerance under a supported convention, but not every vendor uses the same markings.
Worked Example
A code like 102 is commonly read as 10 × 10² µH, or 1,000 µH = 1 mH; `4R7` commonly denotes 4.7 µH.
Where This Tool Can Help
Identify likely nominal inductance while sorting components or checking a schematic against a part marking.
Checking a first design estimate
Use the formula result to choose a likely component range, then test the circuit with real part values and operating conditions.
Learning how a circuit behaves
Change one input at a time and observe the result to see how a resistor, capacitor, inductor, or device parameter affects the calculation.
Comparing candidate components
Compare values on the same unit basis, then check package, tolerance, power rating, voltage rating, and availability in the relevant datasheet.
Reviewing a schematic
Use the result as a cross-check for a hand calculation, simulation, or design note while keeping the assumed topology clear.
Tips for More Reliable Results
- Use consistent units and copy component values carefully, including prefixes such as m, µ, n, and k.
- Check polarity, pin names, and series or parallel placement against the circuit diagram.
- Use worst-case component tolerances when a timing or operating range must stay within limits.
- Verify the result against datasheets and an appropriate bench measurement before building a safety-critical circuit.
Limitations and Assumptions
The result does not provide current rating, saturation current, DCR, core type, package, or frequency behavior. Unrecognized suffixes may have other meanings. Confirm uncertain codes in the component datasheet and use a meter when the value is critical.
The calculator can only model the values, topology, and operating assumptions represented by its inputs. It does not inspect a physical circuit, validate wiring, or confirm a part is safe for its electrical and thermal conditions. Use design documentation and datasheets for final component choices.
Frequently Asked Questions
What does R mean in 4R7?
It is commonly used as a decimal marker, so the value reads 4.7.
Does the converter identify the inductor's current rating?
No. It decodes a nominal inductance marking only.
Are all code conventions the same?
No. Manufacturer and component families can use different codes; verify the datasheet.
Will the result exactly match a real circuit?
Not always. The formula may use ideal components and may not include tolerances, parasitic effects, loading, or temperature changes.
Can I select a component from the calculated value alone?
No. Also check ratings, tolerance, package, polarity, availability, and the circuit's operating conditions.