SMD Resistor Code Calculator

SMD (surface-mount) resistors are tiny components printed with a short numeric or alphanumeric code instead of color bands — the SMD Resistor Code Calculator decodes that marking into an actual resistance value. Select your code format (3-Digit EIA, 4-Digit EIA, or EIA-96) and enter the SMD resistor code printed on the component to get the resistance value in ohms, a formatted value, tolerance, and a step-by-step code breakdown.

Code Format *

Enter the code printed on your SMD resistor

Results

Resistance Value

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Formatted Value

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Tolerance

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Code Breakdown

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Results Table

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Frequently Asked Questions

What is a SMD resistor?

A Surface-Mount Device (SMD) resistor is a passive electronic component designed to be mounted directly onto the surface of a PCB. Unlike through-hole resistors, they don't have wire leads and are much smaller, making them ideal for compact electronic designs.

How do I read a 3-digit SMD resistor code?

In a 3-digit code, the first two digits represent significant figures and the third digit is the multiplier (power of 10). For example, '103' means 10 × 10³ = 10,000Ω = 10kΩ. The letter 'R' indicates a decimal point.

What's the difference between 3-digit and 4-digit SMD codes?

4-digit codes provide higher precision with three significant digits plus one multiplier digit, while 3-digit codes use two significant digits plus one multiplier. For example, '1002' = 100 × 10² = 10kΩ with better precision than '103'.

What is the EIA-96 coding system?

EIA-96 uses a two-digit number (01-96) followed by a letter. The number corresponds to a value from the E96 series, and the letter indicates the multiplier. This system is typically used on 1% tolerance precision resistors.

Can I use a multimeter to verify SMD resistor values?

Yes, using a multimeter is always recommended to double-check critical components. However, be careful when measuring in-circuit as other components may affect the reading. For best results, measure the resistor when removed from the circuit.

What does 'R' mean in SMD resistor codes?

The letter 'R' in SMD codes indicates the position of a decimal point. For example, '1R0' means 1.0Ω, '4R7' means 4.7Ω, and 'R22' means 0.22Ω. This notation is used for values less than 10Ω or when decimal precision is needed.

Why might my calculated value not match the measured value?

Differences can occur due to tolerance ranges (typically ±1%, ±5%), temperature effects, aging, or measurement errors. Standard SMD resistors have tolerances, so a 100Ω ±5% resistor can legitimately measure between 95Ω and 105Ω.

What are common SMD resistor package sizes?

Common SMD resistor packages include 0201 (0.6×0.3mm), 0402 (1.0×0.5mm), 0603 (1.6×0.8mm), 0805 (2.0×1.25mm), 1206 (3.2×1.6mm), and larger sizes. Smaller packages typically have less power dissipation capability.