820 Ω resistor color code
An 820 Ω resistor is Gray, Red, Brown, Gold: 82 × 10 = 820 Ω, ±5%, so anything from 779 to 861 Ω is in spec.
82 × 10 = 820 Ω
5-band version
Gray · Red · Black · Black · Brown = 820 Ω ±1%
820 × 1 = 820 Ω. Range 811.8–828.2 Ω (±1%).
Open the 5-band version
Where you'll meet it
An LED on a 12 V battery
A common indicator light in 12 V projects: a 12 V battery, a red LED and one resistor. The 820 Ω resistor sits between the battery's plus and the LED, and sets the current.
I = (12 V − 2.0 V) / 820 Ω ≈ 12.2 mA
That is bright, and it leaves room under the 20 mA that most standard LEDs are rated for.
A blue or white LED drops about 3.0 V, so the same resistor gives (12 V − 3.0 V) / 820 Ω ≈ 11 mA.
The resistor turns (12.2 mA)² × 820 Ω ≈ 0.122 W into heat. That is about half of what a ¼ W (0.25 W) part can take, so it runs warm; a ½ W part runs cooler.
2.0 V and 20 mA are typical figures for a standard 5 mm red LED. Check your LED's datasheet. A full 12 V lead-acid battery reads about 12.7 V, and in a running car the supply sits near 14.4 V: then (14.4 V − 2.0 V) / 820 Ω ≈ 15.1 mA flows, still under 20 mA, but the resistor runs hotter, so use a ½ W part there. The LED's longer leg goes toward the battery's plus. If it stays dark, turn it round: 12 V backwards is more than the 5 V most LEDs are rated to block.
On SMD parts
Look for 821 or 8200
- 821821 = 82 × 10¹ = 820 Ω (3-digit code).
- 82008200 = 820 × 10⁰ = 820 Ω (4-digit code, usually ±1% parts).
There is no EIA-96 code, because 820 Ω is not an E96 value (the nearest E96 values are 806 Ω and 825 Ω). A part marked 820 is 82 Ω, not 820 Ω.
Don't mix it up
Only band 3 changes
These four share Gray, Red and Gold. Brown (×10) is 820 Ω; black is ten times less and red ten times more.
82 Ωband 3 black- 820 Ωband 3 brownThis page
8.2 kΩband 3 red
82 kΩband 3 orange
Check it with a meter
Read 779–861 Ω
- Take the resistor out of the circuit.
- Set the meter to Ω, range 2 kΩ (or auto).
- Touch one probe to each lead. Keep your fingers off the metal: your body is a resistor too.
- Anything from 779 to 861 Ω is a good ±5% part. A 5-band ±1% part should read 811.8 to 828.2 Ω.
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 820 Ω in a pile?
Practise reading it, and its look-alikes, in the resistor challenge.
Try the resistor challenge820 Ω resistor FAQ
What resistor do I need for an LED on 12 V?
820 Ω is a common choice. With a typical red LED (about 2.0 V) it gives (12 V − 2.0 V) / 820 Ω ≈ 12.2 mA, under the 20 mA most standard LEDs are rated for. The resistor turns about 0.122 W into heat, so a ¼ W part works and a ½ W part stays cooler.
What is the SMD code for an 820 Ω resistor?
821 on 3-digit parts (82 × 10¹) and 8200 on 4-digit parts (820 × 10⁰). There is no EIA-96 code, because 820 Ω is not an E96 value.
What are the 5-band colors for 820 Ω?
Gray, Red, Black, Black, Brown: 820 × 1 = 820 Ω with ±1% tolerance, so 811.8 to 828.2 Ω.
What does 820R mean?
820R is another way to write 820 Ω. The R stands for ohms and sits where the decimal point would be, so 8R2 means 8.2 Ω. With nothing after the R, 820R is exactly 820 Ω.
Bands, ranges and codes come from the same engine as the calculator. Last reviewed .