ELECTRONICS · CALCULATOR

SMD resistor code decoder

Free SMD resistor code decoder: get decoded value from three-digit numeric code. The formula and a worked example are shown; verify against the NEC.

Written by Chameera Sampath · Not yet reviewed by a licensed electrician. See the methodology.

US (NEC) only · NFPA 70 / NEC — locally adopted editionDefaults are US values. Verify the locally adopted NEC edition and project data.Official reference ↗

Project inputs

Measurements

Three-digit numeric code

Updates as inputs change. Unit changes preserve the same physical values.

THE MATH BEHIND THE ANSWER

Method & assumptions

Value = first two digits × 10^(last digit)

Three numeric digits only. EIA-96, decimal letter codes (R/K/M) and manufacturer variants are not decoded.

Results do not check every aspect of an electrical installation. The calculators follow US (NEC) practice only; a regional preset changes defaults such as voltage and units, and no result certifies NEC compliance.

Sources and validation →

Worked example

Three-digit numeric code: 102

Decoded value: 1,000 Ω

This example uses the stated inputs; results for the entered values appear above.

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