2.2 kΩ resistor color code
A 2.2 kΩ resistor is Red, Red, Red, Gold: 22 × 100 = 2,200 Ω, ±5%, so anything from 2.09 to 2.31 kΩ is in spec.
22 × 100 = 2,200 Ω = 2.2 kΩ
5-band version
Red · Red · Black · Brown · Brown = 2.2 kΩ ±1%
220 × 10 = 2,200 Ω = 2.2 kΩ. Range 2.178–2.222 kΩ (±1%).
Open the 5-band version
Where you'll meet it
I2C pull-ups on a 3.3 V sensor bus
I2C devices can only pull the two bus lines, SDA (data) and SCL (clock), down to ground. Nothing drives them high, so each line gets a 2.2 kΩ resistor up to 3.3 V. The drawing shows SDA; SCL is wired the same way.
I = 3.3 V / 2.2 kΩ = 1.5 mA
That current flows through the resistor only while a device holds the line low. Every I2C device must be able to sink 3 mA, so 1.5 mA is comfortable.
On a 5 V bus the same resistor passes 5 V / 2.2 kΩ ≈ 2.27 mA, still under 3 mA. Pull up to the voltage your board's pins work at: never to 5 V on a 3.3 V board.
While the line is low the resistor turns 3.3 V × 1.5 mA ≈ 0.005 W into heat, so any size will do.
Many sensor boards already carry their own pull-ups, often 2.2 kΩ, 4.7 kΩ or 10 kΩ. Several boards on one bus put those resistors in parallel, so check before you add more. A Raspberry Pi already has 1.8 kΩ pull-ups on its I2C pins (GPIO2 and GPIO3): add none there. Long wires or a faster bus can need a different value.
On SMD parts
Look for 222 or 2201
- 222222 = 22 × 10² = 2,200 Ω (3-digit code).
- 22012201 = 220 × 10¹ = 2,200 Ω (4-digit code, usually ±1% parts).
There is no EIA-96 code, because 2.2 kΩ is not an E96 value (the nearest E96 values are 2.15 kΩ and 2.21 kΩ).
Don't mix it up
Only band 3 changes
These four share Red, Red and Gold. Red (×100) is 2.2 kΩ; brown is ten times less and orange ten times more.
220 Ωband 3 brown- 2.2 kΩband 3 redThis page
22 kΩband 3 orange
220 kΩband 3 yellow
Check it with a meter
Read 2.09–2.31 kΩ
- Take the resistor out of the circuit.
- Set the meter to Ω, range 20 kΩ (or auto).
- Touch one probe to each lead. Keep your fingers off the metal: your body is a resistor too.
- Anything from 2.09 to 2.31 kΩ is a good ±5% part. A 5-band ±1% part should read 2.178 to 2.222 kΩ.
A meter has a small error of its own, so a reading a hair outside the range does not prove the part is bad. Measure again with firm contact before you swap it.
Spot it
Can you find 2.2 kΩ in a pile?
Practise reading it, and its look-alikes, in the resistor challenge.
Try the resistor challenge2.2 kΩ resistor FAQ
Why does I2C need pull-up resistors?
I2C chips only ever pull SDA and SCL down to ground; they never push them high. A resistor from each line to the supply pulls it back up when every chip lets go. With 2.2 kΩ on a 3.3 V bus, 3.3 V / 2.2 kΩ = 1.5 mA flows while a line is low, well inside the 3 mA every I2C device must sink.
What is the SMD code for a 2.2 kΩ resistor?
222 on 3-digit parts (22 × 10²) and 2201 on 4-digit parts (220 × 10¹). There is no EIA-96 code, because 2.2 kΩ is not an E96 value.
What are the 5-band colors for 2.2 kΩ?
Red, Red, Black, Brown, Brown: 220 × 10 = 2.2 kΩ with ±1% tolerance, so 2.178 to 2.222 kΩ.
What does 2k2 mean?
2k2 is another way to write 2.2 kΩ. The k sits where the decimal point would be, so the point cannot get lost in small print or on a schematic. In the same way, 4k7 means 4.7 kΩ.
Bands, ranges and codes come from the same engine as the calculator. Last reviewed .