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SMD Resistor Code Calculator

Decode 3-digit, 4-digit, R-decimal, or EIA-96 resistor markings, or enter a resistance to generate a supported code.

Help
Code format:

Detected: 3-Digit EIA

H, R and S are not universal aliases. Match the manufacturer’s datasheet before decoding those letters.

Digits 0–9; one R allowed in position 1 or 2.

Type 47000, 47,000, or 47K. K = ×1,000; M or m = ×1,000,000.

Resistance value1 kΩ

10 × 10² Ω

Decode common SMD resistor markings

Enter a marking in Resistor code to detect its supported format. To generate a marking, enter Resistance, select the unit and desired code format, and check the represented value and conversion difference.

SMD resistor examples
MarkingDecoded value
47247 × 100 Ω = 4.7 kΩ
4991499 × 10 Ω = 4.99 kΩ
4R74.7 Ω (R marks the decimal point)
01CEIA-96 index 01: 100 × 100 Ω = 10 kΩ

For a reverse example, enter 4.73 kΩ. The 4-Digit EIA format represents it exactly as 4731; the 3-Digit EIA format gives 472, representing 4.70 kΩ. The difference is approximately −0.634%, separate from resistor manufacturing tolerance.

Read markings on real resistors

These are decoded nominal values, not meter measurements of the photographed parts. Color and glare can make bands or characters ambiguous. Check the reading direction and the actual component; consult its datasheet or measure resistance when uncertain. In-circuit measurements can include parallel paths.

Surface-mount resistor marked 512 on a circuit board.

512: 5.1 kΩ.

Three-digit numeric marking: the first two digits give 51; the final 2 means ×10². Thus 51 × 100 Ω = 5,100 Ω = 5.1 kΩ. Compare this with the three significant digits used by the four-digit 3922 example.

Enter 512 in the calculator; the visible underline is not another input character.

Surface-mount resistor marked 3922 on a circuit board.

3922: 39.2 kΩ.

Four-digit numeric marking: the first three digits give 392; the final 2 means ×10². Thus 392 × 100 Ω = 39,200 Ω.

Surface-mount resistor marked 48C on a circuit board.

48C: 30.9 kΩ.

EIA-96 index 48 selects 309 from the lookup table; C means ×100. Thus 309 × 100 Ω = 30,900 Ω. The index 48 is a lookup position, not a literal significant value of 48.

Surface-mount resistor marked 11D on a circuit board.

11D: 127 kΩ.

EIA-96 index 11 selects 127; D means ×1,000. Thus 127 × 1,000 Ω = 127,000 Ω. Compare the D multiplier here with C (×100) in the 48C example.

Component photographs supplied by CircuitKitchen.

A photograph or body marking alone does not establish SMD tolerance, power rating, voltage rating, manufacturer or package size. In particular, a four-digit numeric format is not proof of ±1% tolerance.

How calculations are checked

Automated checks compare supported numeric, R-decimal and EIA-96 decoding and encoding with expected values, exercise equivalent multiplier letters and rounding, and reject malformed or out-of-range codes. The About page describes the original spreadsheet and hand-calculation process. These checks verify the marking conversions; they are not physical component measurements.

Use a decoded value in the voltage divider calculator to check loading and output tolerance.

How to use

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Using the calculator

Type an SMD resistor marking to decode it. The calculator automatically detects the supported format when possible.

You can also enter a resistance and select the code format you want to use. The calculator generates the corresponding marking. If the selected format cannot represent the requested resistance exactly, it shows the nearest representable value and the difference from your request.

When a value cannot be represented exactly

Each marking format can represent only a specific set of resistance values.

The visible reverse-generation example compares the same requested resistance in two formats.

When the requested value cannot be represented exactly, the calculator shows the nearest representable resistance and its percentage difference from the requested value.

That difference is a code-conversion difference, not the resistor's manufacturing tolerance.

Zero-ohm links and unmarked parts

An all-zero numeric marking commonly identifies a zero-ohm jumper, which is used as a connection in a resistor-style package. A zero-ohm jumper still has a small real resistance and a current limit.

Some chip resistors have no printed marking at all. An unmarked component does not mean zero ohms.

EIA-96 does not define a zero-ohm code.

What the marking cannot tell you

An SMD marking identifies or helps identify the nominal resistance, but it does not provide every specification needed to select the component.

Use the manufacturer's datasheet to verify:

  • tolerance
  • power rating and derating
  • maximum working voltage
  • temperature coefficient and operating-temperature limits
  • package and construction
  • manufacturer-specific marking conventions

An unsupported marking may use another convention. Do not infer a missing character from a damaged or incomplete marking when selecting a replacement.

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Theory & formulas

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3-Digit EIA codes

A 3-Digit EIA code uses two significant digits followed by a power-of-ten multiplier.

See the visible marking examples for a 3-digit calculation. These markings are commonly used on general-purpose resistors, but the marking itself does not specify or guarantee the resistor tolerance.

A final zero means multiply by one: 470 = 47 Ω.

4-Digit EIA codes

A 4-Digit EIA code uses three significant digits followed by a power-of-ten multiplier.

The extra significant digit allows more resistance values to be represented than with the 3-digit format. These markings are commonly used on precision resistors when package size permits, but the marking itself does not guarantee tolerance.

R-decimal notation

For low resistance values, R can replace the decimal point:

  • 4R7 = 4.7 Ω
  • 4R70 = 4.70 Ω
  • R47 = 0.47 Ω

There is no separate multiplier digit in an R-decimal marking.

For the formats supported by this calculator, use at most one R. In a three-character code it may appear in position 1 or 2; in a four-character code it may appear in position 1, 2, or 3.

EIA-96 codes

The EIA-96 SMD marking system is based specifically on the E96 preferred-value series.

An EIA-96 marking contains:

two digits from 01 through 96 + one multiplier letter

The two-digit number is an index into the E96 preferred-value table; it is not the resistance itself. The final letter supplies the multiplier.

See the visible 01C example for the index-and-multiplier calculation.

Keep the leading zero in indexes 01 through 09.

The E96 series is one member of the broader E-series family of preferred resistor values. Use the shared reference for E3 through E192, commonly associated tolerances, value spacing, and complete preferred-value tables.

Open E-series reference below

EIA-96 multiplier letters

The final character of an EIA-96 marking determines the multiplier.

EIA-96 multiplier letters
LetterMultiply by
Z×0.001
Y×0.01
X×0.1
A×1
B×10
C×100
D×1,000
E×10,000
F×100,000

The default common convention supports A–F and X–Z without ambiguous aliases. Select TT Electronics for S/Y = ×0.01, R/X = ×0.1 and H/B = ×10. Select Bourns CR for G = ×10⁶ and H = ×10⁷.

In EIA-96 notation, R is a multiplier letter rather than a decimal point. For example:

47R requires TT Electronics selected: 301 × 0.1 Ω = 30.1 Ω

Context matters. If another digit is added to make 47R0, the calculator recognizes the marking as 4-Digit EIA R-decimal notation instead and interprets it as:

47R0 = 47.0 Ω

EIA-96 base values

EIA-96 index to base value
Index / valueIndex / valueIndex / valueIndex / value
01 / 10025 / 17849 / 31673 / 562
02 / 10226 / 18250 / 32474 / 576
03 / 10527 / 18751 / 33275 / 590
04 / 10728 / 19152 / 34076 / 604
05 / 11029 / 19653 / 34877 / 619
06 / 11330 / 20054 / 35778 / 634
07 / 11531 / 20555 / 36579 / 649
08 / 11832 / 21056 / 37480 / 665
09 / 12133 / 21557 / 38381 / 681
10 / 12434 / 22158 / 39282 / 698
11 / 12735 / 22659 / 40283 / 715
12 / 13036 / 23260 / 41284 / 732
13 / 13337 / 23761 / 42285 / 750
14 / 13738 / 24362 / 43286 / 768
15 / 14039 / 24963 / 44287 / 787
16 / 14340 / 25564 / 45388 / 806
17 / 14741 / 26165 / 46489 / 825
18 / 15042 / 26766 / 47590 / 845
19 / 15443 / 27467 / 48791 / 866
20 / 15844 / 28068 / 49992 / 887
21 / 16245 / 28769 / 51193 / 909
22 / 16546 / 29470 / 52394 / 931
23 / 16947 / 30171 / 53695 / 953
24 / 17448 / 30972 / 54996 / 976
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E-series resistor values

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E-series are standardized sets of preferred nominal resistance values defined by IEC 60063. They provide a consistent selection of values for circuit design and component manufacturing.

The nominal resistance is the specified value of a resistor. Its actual resistance may differ within its stated tolerance. The E-series identifies a set of nominal values; tolerance describes the permitted variation around a selected value.

Values per decade

The number following E indicates how many unique nominal values the series contains per decade. A decade spans a factor of ten, such as 100 Ω to below 1 kΩ or 1 kΩ to below 10 kΩ.

E6, for example, contains these six values between 1 kΩ and 10 kΩ: 1.0 kΩ, 1.5 kΩ, 2.2 kΩ, 3.3 kΩ, 4.7 kΩ, and 6.8 kΩ.

The pattern repeats in other decades by multiplying or dividing by powers of ten. The 10 kΩ boundary begins the next decade, so it is not counted twice.

Series and commonly associated tolerances

SeriesValues per decadeSignificant digitsCommonly associated tolerances
E332No tolerance association listed in the cited Vishay table
E662±20%
E12122±10%
E24242±5%
E48483±2%
E96963±1%
E1921923±0.5%, ±0.25%, ±0.1%

These are conventional associations, not limits on the tolerances available for each value. Manufacturers offer preferred values at multiple tolerances, depending on the product family, resistance range, and package. Check the component datasheet for available combinations.

For example, a nominal 10 kΩ resistor with ±1% tolerance has resistance limits of 9.90 kΩ and 10.10 kΩ under the specified datasheet conditions.

Rmin = Rnominal × (1 − t) Rmax = Rnominal × (1 + t)

Use 0.01 for ±1%. E3, E6, E12, and E24 form one nested group. E48, E96, and E192 form another. E24 is not fully contained in E192: for example, E24 includes 2.2 kΩ, while E192 includes nearby 2.21 kΩ.

All E-series

All E-series searches every preferred resistance value in E24, E48, E96, and E192, with duplicates removed. This also includes E3, E6, and E12 values.

The combined set contains 205 unique values per decade. It is formed by combining E24 and E192, which together cover all the series listed above.

Choose this option for the broadest selection of values supported by the calculator, then check your distributor for components with the required tolerance, ratings, availability, and price. If a suggested component is unavailable or unsuitable, evaluate another suggested value or an available value from the distributor’s catalog.

All E-series is a calculator search category, not a separate standardized E-series. It does not include every custom or nonstandard resistance sold by manufacturers, and it does not guarantee that a particular component is stocked.

Choosing preferred values

Choose All E-series when you want a broad search and plan to source components from a distributor. Choose an individual series when you want to match an existing inventory or a manufacturer’s product range.

Select tolerance separately. The preferred-value set determines which nominal resistances are considered; tolerance determines the resistance variation used in the calculations.

A closer nominal match does not necessarily produce the best worst-case circuit performance. Compare the calculated circuit results with the selected values and tolerances, as well as the component ratings.

A practical resistor-selection workflow

  1. Define the circuit requirements. Establish the desired resistance or circuit output, acceptable error, operating conditions, and relevant size, voltage, and power constraints.
  2. Calculate the ideal value. Determine the resistance that would produce the desired result with ideal components.
  3. Select preferred values and tolerance. Choose All E-series for a broad search, or an individual series to match your sourcing requirements. Set the tolerance you intend to purchase.
  4. Compare circuit performance. Review nominal and worst-case results using the suggested values. Check resistor power dissipation and the recommended power rating. For resistor combinations, evaluate the complete circuit as well as each resistor.
  5. Find suitable components. Search a distributor’s catalog for the selected resistance and tolerance. Check package, rated power and derating, temperature coefficient, voltage rating, stock, lead time, and price at your required quantity. Check pulse capability when applicable.
  6. Evaluate alternatives when necessary. If a component is unavailable or unsuitable, consider another suggested value or enter an available value into the calculator. Recalculate with the tolerance of the actual component you intend to buy.
  7. Specify the selected component. Record the manufacturer’s part number and relevant specifications in the bill of materials. Verify the datasheet ratings and operating conditions before finalizing the design.

The goal is to select components that meet the circuit requirements and can be sourced at an acceptable price. The closest nominal resistance is a useful starting point; the final selection also depends on tolerance, operating limits, and availability.

E-series and component price

A larger E-series does not automatically mean a higher component price. Different resistance values within the same product family may have identical or similar prices, while particular values can differ in price, stock, or lead time.

Compare actual components with the same relevant specifications, purchase quantity, and packaging. Use the calculator to evaluate electrical performance and the distributor’s catalog to confirm purchasing options.

How preferred values are spaced

E-series values follow approximately equal percentage steps rather than equal differences in ohms. For a series with N values per decade, the ideal adjacent-value ratio is 101/N.

Ideal step = 100 × (101/N − 1)%

This is approximately 10.1% for E24 and 2.43% for E96. Actual tabulated steps vary because the standardized values use rounded numbers.

Use the published preferred-value tables when selecting components. The formula explains the approximate spacing; it does not replace the standardized tables.

Preferred-value tables

Each table lists every preferred value within one decade, normalized from 1 up to—but not including—10. Multiply an entry by a power of ten to obtain resistance values in other decades. For example, 4.7 represents 4.7 Ω, 47 Ω, 470 Ω, 4.7 kΩ, 47 kΩ, and so on. Inclusion in a table does not guarantee availability in a particular tolerance or package.

E3 — 3 values per decade
  • 1.0
  • 2.2
  • 4.7
E6 — 6 values per decade
  • 1.0
  • 1.5
  • 2.2
  • 3.3
  • 4.7
  • 6.8
E12 — 12 values per decade
  • 1.0
  • 1.2
  • 1.5
  • 1.8
  • 2.2
  • 2.7
  • 3.3
  • 3.9
  • 4.7
  • 5.6
  • 6.8
  • 8.2
E24 — 24 values per decade
  • 1.0
  • 1.1
  • 1.2
  • 1.3
  • 1.5
  • 1.6
  • 1.8
  • 2.0
  • 2.2
  • 2.4
  • 2.7
  • 3.0
  • 3.3
  • 3.6
  • 3.9
  • 4.3
  • 4.7
  • 5.1
  • 5.6
  • 6.2
  • 6.8
  • 7.5
  • 8.2
  • 9.1
E48 — 48 values per decade
  • 1.00
  • 1.05
  • 1.10
  • 1.15
  • 1.21
  • 1.27
  • 1.33
  • 1.40
  • 1.47
  • 1.54
  • 1.62
  • 1.69
  • 1.78
  • 1.87
  • 1.96
  • 2.05
  • 2.15
  • 2.26
  • 2.37
  • 2.49
  • 2.61
  • 2.74
  • 2.87
  • 3.01
  • 3.16
  • 3.32
  • 3.48
  • 3.65
  • 3.83
  • 4.02
  • 4.22
  • 4.42
  • 4.64
  • 4.87
  • 5.11
  • 5.36
  • 5.62
  • 5.90
  • 6.19
  • 6.49
  • 6.81
  • 7.15
  • 7.50
  • 7.87
  • 8.25
  • 8.66
  • 9.09
  • 9.53
E96 — 96 values per decade
  • 1.00
  • 1.02
  • 1.05
  • 1.07
  • 1.10
  • 1.13
  • 1.15
  • 1.18
  • 1.21
  • 1.24
  • 1.27
  • 1.30
  • 1.33
  • 1.37
  • 1.40
  • 1.43
  • 1.47
  • 1.50
  • 1.54
  • 1.58
  • 1.62
  • 1.65
  • 1.69
  • 1.74
  • 1.78
  • 1.82
  • 1.87
  • 1.91
  • 1.96
  • 2.00
  • 2.05
  • 2.10
  • 2.15
  • 2.21
  • 2.26
  • 2.32
  • 2.37
  • 2.43
  • 2.49
  • 2.55
  • 2.61
  • 2.67
  • 2.74
  • 2.80
  • 2.87
  • 2.94
  • 3.01
  • 3.09
  • 3.16
  • 3.24
  • 3.32
  • 3.40
  • 3.48
  • 3.57
  • 3.65
  • 3.74
  • 3.83
  • 3.92
  • 4.02
  • 4.12
  • 4.22
  • 4.32
  • 4.42
  • 4.53
  • 4.64
  • 4.75
  • 4.87
  • 4.99
  • 5.11
  • 5.23
  • 5.36
  • 5.49
  • 5.62
  • 5.76
  • 5.90
  • 6.04
  • 6.19
  • 6.34
  • 6.49
  • 6.65
  • 6.81
  • 6.98
  • 7.15
  • 7.32
  • 7.50
  • 7.68
  • 7.87
  • 8.06
  • 8.25
  • 8.45
  • 8.66
  • 8.87
  • 9.09
  • 9.31
  • 9.53
  • 9.76
E192 — 192 values per decade
  • 1.00
  • 1.01
  • 1.02
  • 1.04
  • 1.05
  • 1.06
  • 1.07
  • 1.09
  • 1.10
  • 1.11
  • 1.13
  • 1.14
  • 1.15
  • 1.17
  • 1.18
  • 1.20
  • 1.21
  • 1.23
  • 1.24
  • 1.26
  • 1.27
  • 1.29
  • 1.30
  • 1.32
  • 1.33
  • 1.35
  • 1.37
  • 1.38
  • 1.40
  • 1.42
  • 1.43
  • 1.45
  • 1.47
  • 1.49
  • 1.50
  • 1.52
  • 1.54
  • 1.56
  • 1.58
  • 1.60
  • 1.62
  • 1.64
  • 1.65
  • 1.67
  • 1.69
  • 1.72
  • 1.74
  • 1.76
  • 1.78
  • 1.80
  • 1.82
  • 1.84
  • 1.87
  • 1.89
  • 1.91
  • 1.93
  • 1.96
  • 1.98
  • 2.00
  • 2.03
  • 2.05
  • 2.08
  • 2.10
  • 2.13
  • 2.15
  • 2.18
  • 2.21
  • 2.23
  • 2.26
  • 2.29
  • 2.32
  • 2.34
  • 2.37
  • 2.40
  • 2.43
  • 2.46
  • 2.49
  • 2.52
  • 2.55
  • 2.58
  • 2.61
  • 2.64
  • 2.67
  • 2.71
  • 2.74
  • 2.77
  • 2.80
  • 2.84
  • 2.87
  • 2.91
  • 2.94
  • 2.98
  • 3.01
  • 3.05
  • 3.09
  • 3.12
  • 3.16
  • 3.20
  • 3.24
  • 3.28
  • 3.32
  • 3.36
  • 3.40
  • 3.44
  • 3.48
  • 3.52
  • 3.57
  • 3.61
  • 3.65
  • 3.70
  • 3.74
  • 3.79
  • 3.83
  • 3.88
  • 3.92
  • 3.97
  • 4.02
  • 4.07
  • 4.12
  • 4.17
  • 4.22
  • 4.27
  • 4.32
  • 4.37
  • 4.42
  • 4.48
  • 4.53
  • 4.59
  • 4.64
  • 4.70
  • 4.75
  • 4.81
  • 4.87
  • 4.93
  • 4.99
  • 5.05
  • 5.11
  • 5.17
  • 5.23
  • 5.30
  • 5.36
  • 5.42
  • 5.49
  • 5.56
  • 5.62
  • 5.69
  • 5.76
  • 5.83
  • 5.90
  • 5.97
  • 6.04
  • 6.12
  • 6.19
  • 6.26
  • 6.34
  • 6.42
  • 6.49
  • 6.57
  • 6.65
  • 6.73
  • 6.81
  • 6.90
  • 6.98
  • 7.06
  • 7.15
  • 7.23
  • 7.32
  • 7.41
  • 7.50
  • 7.59
  • 7.68
  • 7.77
  • 7.87
  • 7.96
  • 8.06
  • 8.16
  • 8.25
  • 8.35
  • 8.45
  • 8.56
  • 8.66
  • 8.76
  • 8.87
  • 8.98
  • 9.09
  • 9.20
  • 9.31
  • 9.42
  • 9.53
  • 9.65
  • 9.76
  • 9.88
All E-series — 205 values per decade

Combined E24 and E192 values, with duplicates removed.

  • 1.00
  • 1.01
  • 1.02
  • 1.04
  • 1.05
  • 1.06
  • 1.07
  • 1.09
  • 1.10
  • 1.11
  • 1.13
  • 1.14
  • 1.15
  • 1.17
  • 1.18
  • 1.20
  • 1.21
  • 1.23
  • 1.24
  • 1.26
  • 1.27
  • 1.29
  • 1.30
  • 1.32
  • 1.33
  • 1.35
  • 1.37
  • 1.38
  • 1.40
  • 1.42
  • 1.43
  • 1.45
  • 1.47
  • 1.49
  • 1.50
  • 1.52
  • 1.54
  • 1.56
  • 1.58
  • 1.60
  • 1.62
  • 1.64
  • 1.65
  • 1.67
  • 1.69
  • 1.72
  • 1.74
  • 1.76
  • 1.78
  • 1.80
  • 1.82
  • 1.84
  • 1.87
  • 1.89
  • 1.91
  • 1.93
  • 1.96
  • 1.98
  • 2.00
  • 2.03
  • 2.05
  • 2.08
  • 2.10
  • 2.13
  • 2.15
  • 2.18
  • 2.20
  • 2.21
  • 2.23
  • 2.26
  • 2.29
  • 2.32
  • 2.34
  • 2.37
  • 2.40
  • 2.43
  • 2.46
  • 2.49
  • 2.52
  • 2.55
  • 2.58
  • 2.61
  • 2.64
  • 2.67
  • 2.70
  • 2.71
  • 2.74
  • 2.77
  • 2.80
  • 2.84
  • 2.87
  • 2.91
  • 2.94
  • 2.98
  • 3.00
  • 3.01
  • 3.05
  • 3.09
  • 3.12
  • 3.16
  • 3.20
  • 3.24
  • 3.28
  • 3.30
  • 3.32
  • 3.36
  • 3.40
  • 3.44
  • 3.48
  • 3.52
  • 3.57
  • 3.60
  • 3.61
  • 3.65
  • 3.70
  • 3.74
  • 3.79
  • 3.83
  • 3.88
  • 3.90
  • 3.92
  • 3.97
  • 4.02
  • 4.07
  • 4.12
  • 4.17
  • 4.22
  • 4.27
  • 4.30
  • 4.32
  • 4.37
  • 4.42
  • 4.48
  • 4.53
  • 4.59
  • 4.64
  • 4.70
  • 4.75
  • 4.81
  • 4.87
  • 4.93
  • 4.99
  • 5.05
  • 5.10
  • 5.11
  • 5.17
  • 5.23
  • 5.30
  • 5.36
  • 5.42
  • 5.49
  • 5.56
  • 5.60
  • 5.62
  • 5.69
  • 5.76
  • 5.83
  • 5.90
  • 5.97
  • 6.04
  • 6.12
  • 6.19
  • 6.20
  • 6.26
  • 6.34
  • 6.42
  • 6.49
  • 6.57
  • 6.65
  • 6.73
  • 6.80
  • 6.81
  • 6.90
  • 6.98
  • 7.06
  • 7.15
  • 7.23
  • 7.32
  • 7.41
  • 7.50
  • 7.59
  • 7.68
  • 7.77
  • 7.87
  • 7.96
  • 8.06
  • 8.16
  • 8.20
  • 8.25
  • 8.35
  • 8.45
  • 8.56
  • 8.66
  • 8.76
  • 8.87
  • 8.98
  • 9.09
  • 9.10
  • 9.20
  • 9.31
  • 9.42
  • 9.53
  • 9.65
  • 9.76
  • 9.88

Sources

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Sources and manufacturer differences

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Multiplier letters vary by manufacturer. Select the convention matching the part. The common default rejects G, H, R and S. TT Electronics and Bourns extensions are decoded only after an explicit selection; H means ×10 in TT’s table and ×10⁷ for Bourns. Do not use the supported alias table as a universal identification rule. Confirm an ambiguous letter against the actual manufacturer’s datasheet; the marking does not establish all component specifications.

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