Which end do I start reading from?

The end with the bands grouped closest together. On most resistors the tolerance band is separated by a wider gap, and it is gold or silver — colours that never appear as a first digit. If both ends look the same, measure it: reading backwards turns a 1 kΩ into a 100 Ω or worse.

What is the difference between four and five bands?

A fifth band adds a third significant digit, so 1 kΩ can be marked as 1-0-0-brown rather than 1-0-red. Five-band parts are usually 1% or better, and the extra digit is what that precision needs — you cannot express 4.99 kΩ in two digits.

Why are resistor values such odd numbers?

Because they are spaced by tolerance rather than by round numbers. The E24 series used for 5% parts steps by about 10% — 10, 11, 12, 13, 15, 16, 18 — so that consecutive values just touch at their tolerance edges and every possible resistance is covered by something. 4.7 kΩ is not arbitrary, it is where the ladder lands.

What do gold and silver mean as a multiplier?

Division rather than multiplication: gold divides by ten and silver by a hundred. That is how sub-ten-ohm values are marked — brown, black, gold is 1.0 Ω. The same two colours mean tolerance in the last position, which is the other reason reading from the correct end matters.

Resistor Colour Code Calculator

Resistance is 1,000.00 Ω. It is reached in 9 steps, the last of which is (1 * 10 + 0) * 100, and each one is printed on the page with its numbers filled in. The formula is the one published by Electronic colour code, not an approximation fitted to it.

Resistance and tolerance from the bands on a resistor, with the E-series value it is meant to be.

Formula and sources checked 27 August 2026 · How we check

First band Brown — 1, Second band Black — 0, Multiplier band Red — ×100, Tolerance band Gold — ±5%

1,000.00 Ω

Resistance for the example below. Editing a field recomputes the calculator below; this figure holds the answer the page was loaded with.

It is written into the HTML rather than drawn by a script, so a search engine reading this page without running JavaScript still finds an answer.

First bandSecond bandMultiplier bandTolerance band

Resistance

1,000.00 Ω

First digit: 1
Second digit: 0
Multiplier: 100
Resistance: (1 * 10 + 0) * 1001,000 Ω
Tolerance: 5 %
Lowest value in tolerance: 1000 * (1 - 5 / 100)950 Ω
Highest value in tolerance: 1000 * (1 + 5 / 100)1,050 Ω
In kilohms: 1000 / 10001 kΩ
Steps in the E-series for this tolerance: 24

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Worked example

Brown, black, red, gold is 1, 0, ×100 — a 1,000 Ω resistor at ±5%, so anywhere from 950 to 1,050 Ω is within specification. It is the commonest resistor in a hobby drawer and the one worth learning to read on sight.

How to work it out yourself

1.Read from the end where the bands are closest together. The tolerance band sits alone at the other end, usually gold or silver, and starting from the wrong end reverses the digits.
2.Two digits and a multiplier is the four-band code. A five-band resistor has three digits and a multiplier and is a precision part; the reading rule is otherwise the same.
3.Check the tolerance range before assuming a measurement is wrong. A meter reading three per cent off the marked value on a ±5% part is reading a good resistor, not a faulty one.

The formula

First digit
Second digit
Multiplier
Resistance(1 * 10 + 0) * 100
Tolerance
Lowest value in tolerance1000 * (1 - 5 / 100)
Highest value in tolerance1000 * (1 + 5 / 100)
In kilohms1000 / 1000
Steps in the E-series for this tolerance

Source: Electronic colour code — the IEC 60062 band scheme, explained, NIST Special Publication 811 — Guide for the Use of the International System of Units

Questions people actually ask

Which end do I start reading from?: The end with the bands grouped closest together. On most resistors the tolerance band is separated by a wider gap, and it is gold or silver — colours that never appear as a first digit. If both ends look the same, measure it: reading backwards turns a 1 kΩ into a 100 Ω or worse.
What is the difference between four and five bands?: A fifth band adds a third significant digit, so 1 kΩ can be marked as 1-0-0-brown rather than 1-0-red. Five-band parts are usually 1% or better, and the extra digit is what that precision needs — you cannot express 4.99 kΩ in two digits.
Why are resistor values such odd numbers?: Because they are spaced by tolerance rather than by round numbers. The E24 series used for 5% parts steps by about 10% — 10, 11, 12, 13, 15, 16, 18 — so that consecutive values just touch at their tolerance edges and every possible resistance is covered by something. 4.7 kΩ is not arbitrary, it is where the ladder lands.
What do gold and silver mean as a multiplier?: Division rather than multiplication: gold divides by ten and silver by a hundred. That is how sub-ten-ohm values are marked — brown, black, gold is 1.0 Ω. The same two colours mean tolerance in the last position, which is the other reason reading from the correct end matters.

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