Check a 1k resistor in the calculator
The calculator is set to 1 kΩ with a gold tolerance band. Switch to 5 or 6 bands, change the tolerance, or choose “Read the bands” to decode a resistor you are holding.
1k resistor colour bands
A 1 kΩ resistor carries the same value in every marking system; only the number of bands changes. Read from the end with the bands bunched closest to it, with the tolerance band, usually gold or brown and set slightly apart, on the right.
| Marking | Colours | Drawing | Where you see it |
|---|---|---|---|
| 4 bands, ±5 % | brown, black, red, gold | The most common through-hole marking | |
| 5 bands, ±1 % | brown, black, black, brown, brown | Precision metal-film resistors | |
| 6 bands, ±1 %, 100 ppm/K | brown, black, black, brown, brown, brown | Adds a temperature-coefficient band | |
| 3 bands, ±20 % | brown, black, red | Old parts with no tolerance band |
How to read brown, black, red, gold
- First band, brown: first digit 1.
- Second band, black: second digit 0, giving 10.
- Third band, red: multiply by 100, giving 1,000 Ω = 1 kΩ.
- Fourth band, gold: tolerance ±5 %.
On the 5-band version the first three bands are digits (100) and the fourth is the multiplier (×10), which comes to the same 1 kΩ. Check any other combination with the resistor color code calculator.
What a 1k resistor should measure
Tolerance is how far the real resistance may sit from the marked value. Measured out of circuit with a meter, a good 1 kΩ resistor reads within these limits:
| Tolerance | Band | Lowest | Highest |
|---|---|---|---|
| ±1 % | Brown | 990 Ω | 1.01 kΩ |
| ±2 % | Red | 980 Ω | 1.02 kΩ |
| ±5 % | Gold | 950 Ω | 1.05 kΩ |
| ±10 % | Silver | 900 Ω | 1.1 kΩ |
| ±20 % | None (no band) | 800 Ω | 1.2 kΩ |
Measure it out of circuit, or with one leg lifted: anything connected in parallel in the circuit pulls the reading down. Set a manual meter to the first range above 1 kΩ.
Is 1k a standard resistor value?
Yes. 1 kΩ belongs to the E3, E6, E12, E24, E48, E96, E192 series of IEC 60063, so it is made in every tolerance from ±20 % down to ±0.1 %. The neighbouring E12 values are 820 Ω below and 1.2 kΩ above. All the series are listed on our E-series resistor values page.
SMD code for 1 kΩ
- 3-digit code (usually ±5 %):
102. - 4-digit code (usually ±1 %):
1001. - EIA-96 code (±1 % chips in 0603 and smaller):
01B: code 1 for the digits, the letter for the multiplier.
Decode any chip marking with the SMD resistor code calculator.
Current, power and wattage
By Ohm’s law, I = V ÷ R and P = V² ÷ R. With the whole supply across a 1 kΩ resistor:
| Across | Current | Power | Rating to use |
|---|---|---|---|
| 3.3 V | 3.3 mA | 10.9 mW | ⅛ W |
| 5 V | 5 mA | 25 mW | ⅛ W |
| 12 V | 12 mA | 144 mW | ½ W |
| 24 V | 24 mA | 576 mW | 2 W |
A ¼ W 1 kΩ resistor reaches its full rating at 15.8 V (V = √(P × R)). In series with a red LED (about 2 V) on a 5 V supply it passes 3 mA. The LED resistor calculator finds the right value for any LED and supply.
What a 1k resistor is used for
1 kΩ is one of the most used resistor values. It is the standard LED resistor for 12 V, a typical transistor base resistor for switching a relay or buzzer from a logic pin, and a safe series resistor on microcontroller inputs. Pairs of 1 kΩ resistors make a divide-by-two voltage divider.
Mistakes when reading a 1k resistor
The multiplier band moves the value by a factor of ten for every colour step, so it is the band to check twice, in good light. These are the misreadings that catch people out with 1 kΩ:
- Red read as brown. Brown, black, brown, gold would be 100 Ω, 10 times too low.
- Red read as orange. Brown, black, orange, gold would be 10 kΩ, 10 times too high.
- Reading the 4-band code backwards. It can’t be done: gold is not a digit colour, which is how you know which end comes first.
- Reading the 5-band code backwards. Brown, brown, black, black, brown reads as 110 Ω ±1 %, a plausible value, so this mistake goes unnoticed. The tolerance band is usually a little apart from the others; if you can’t tell, measure it.
Making 1 kΩ from other values
No 1 kΩ in the drawer? Two common E12 values can stand in, within 1 %: in series, 180 Ω + 820 Ω = 1 kΩ; 330 Ω + 680 Ω = 1.01 kΩ; in parallel, 1.8 kΩ ∥ 2.2 kΩ = 990 Ω. Two 1 kΩ resistors give 2 kΩ in series and 500 Ω in parallel.
Colour codes for other common values
- 1 ohm resistor: brown, black, gold
- 100 ohm resistor: brown, black, brown
- 220 ohm resistor: red, red, brown
- 330 ohm resistor: orange, orange, brown
- 470 ohm resistor: yellow, violet, brown
- 4.7k resistor: yellow, violet, red
- 10k resistor: brown, black, orange
- 100k resistor: brown, black, yellow
- 1M resistor: brown, black, green
Colours follow IEC 60062:2016. Codes, ranges and currents on this page are computed by the same engine as the resistor colour code calculator; see our methodology.