CircuitCalc

SMD Resistor Code Calculator

Decode 3-digit (5%), 4-digit (1%), and EIA-96 precision surface-mount resistor codes with reverse lookup and chip visualization.

Common Bench Markings:
Surface Mount Component View
4701
Decoded Resistance
4.7 kΩ
Ohms (Ω)
4700 Ω
Encoding Standard
4-digit (E96 1%)
Standard Tolerance
±1%
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Engineering Principles & Formulas

Unlike axial through-hole resistors which utilize colored bands, Surface Mount Device (SMD) resistors have flat ceramic packages with printed silkscreen alphanumeric markings. Three primary coding systems exist:

3-Digit System (±5% E24):
• 1st & 2nd digits: Value
• 3rd digit: Multiplier 10^n
Example: 472 = 47 × 10² = 4,700 Ω = 4.7 kΩ
4-Digit System (±1% E96):
• 1st, 2nd, 3rd: Value
• 4th digit: Multiplier 10^n
Example: 4701 = 470 × 10¹ = 4,700 Ω = 4.7 kΩ
EIA-96 System (±1% Precision):
• 2 Digits: Lookup code (01-96)
• 1 Letter: Multiplier letter
Example: 01C = 100 × 100 = 10,000 Ω = 10 kΩ

Zero-Ohm Jumpers & "R" Decimal Markers

A single 0, 000, or 0000 designates a zero-ohm link used as a jumper to bridge PCB traces without adding component cost. For fractional resistances under 10 \(\Omega\), the letter R acts as a decimal point (e.g. 4R7 = 4.7 \(\Omega\); 0R22 = 0.22 \(\Omega\)).

Reference Table & Standards

EIA-96 Multiplier Letter Table (Used on 0603 1% SMD Resistors)
Z×0.001
Y×0.01
X×0.1
S×0.01
R×0.1
A×1
B×10
C×100
D×1000
E×10000
F×100000
Popular EIA-96 Codes: 01 = 100 | 13 = 133 | 25 = 178 | 37 = 237 | 49 = 316 | 68 = 499 | 85 = 750
BENCH PARTNER // SPONSOREDID: smd-resi
Precision Instrument SpaceReserved for relevant test equipment, PCB manufacturing & component sourcing partners.

Continuous Calculation Chain

Electronics engineering workflows naturally connect. Continue your calculation with pre-filled parameters:

Resistor Color Code

Look up axial through-hole equivalents for breadboard prototyping.

Launch Tool & Carry Values→
Ohm's Law Calculator

Verify chip power dissipation against standard package ratings (0805, 0603, 0402).

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PCB Trace Width

Size copper pads and routing traces for this surface-mount component.

Launch Tool & Carry Values→

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Frequently Asked Questions

Why do some 0402 or 0201 SMD resistors have no markings at all?

Modern ultra-compact SMD chip resistors (0402, 0201, and 01005) are too tiny for silkscreen printing. They arrive in labeled reels and must be measured with an LCR meter or multimeter once removed from the carrier tape.

What is the typical power rating for standard SMD packages?

Standard thick-film ratings are: 1206 (1/4 W = 250 mW), 0805 (1/8 W = 125 mW), 0603 (1/10 W = 100 mW), and 0402 (1/16 W = 62.5 mW).