1 MΩ resistor color code
A 1 MΩ resistor is Brown, Black, Green, Gold: 10 × 100,000 = 1,000,000 Ω, ±5%, so anything from 950,000 to 1,050,000 Ω is in spec.
10 × 100,000 = 1,000,000 Ω = 1 MΩ
5-band version
Brown · Black · Black · Yellow · Brown = 1 MΩ ±1%
100 × 10,000 = 1,000,000 Ω = 1 MΩ. Range 990,000–1,010,000 Ω (±1%).
Open the 5-band version
Where you'll meet it
A touch button with no moving parts
The Arduino CapacitiveSensor library turns a piece of foil into a button. Pin D4 sends a pulse through a 1 MΩ resistor to pin D6, which has the foil attached. A finger on the foil adds capacitance, the pulse arrives later, and the library counts the delay.
τ = 1 MΩ × 100 pF = 0.1 ms
With a finger on the foil, the receive pin takes roughly τ (tau) to follow the send pin. 100 pF is the usual round figure for a human body; the real value varies with the foil and the wiring.
1 MΩ is the value the library's guide gives for a pad that must actually be touched: a hand that only comes near changes the delay too little to count.
Almost no current flows: at most 5 V / 1 MΩ = 5 µA.
The hand is drawn as a capacitor to ground because that is how it behaves; it is not a part you add. The foil still works under a layer of tape or paper. Readings change with the foil size, the wiring and how the board is powered (it works best when the board's ground is connected to earth, as on a laptop that is charging), so expect to tune the threshold in code.
On SMD parts
Look for 105, 1004 or 01E
- 105105 = 10 × 10⁵ = 1,000,000 Ω (3-digit code).
- 10041004 = 100 × 10⁴ = 1,000,000 Ω (4-digit code, usually ±1% parts).
- 01E01E = 100 × 10,000 = 1,000,000 Ω (EIA-96: 01 means 100, E means ×10,000).
1 MΩ has an EIA-96 code because 100 is the first value in the E96 series.
Don't mix it up
Only band 3 changes
These four share Brown, Black and Gold. Green (×100,000) is 1 MΩ; yellow is ten times less and blue ten times more.
10 kΩband 3 orange
100 kΩband 3 yellow- 1 MΩband 3 greenThis page
10 MΩband 3 blue
Check it with a meter
Read 950,000–1,050,000 Ω
- Take the resistor out of the circuit.
- Set the meter to Ω, range 2 MΩ (or auto).
- Touch one probe to each lead. Keep your fingers off the metal: your body is a resistor too. At 1 MΩ this matters a lot: with a finger on each lead the meter measures you as well, and the reading drops.
- Anything from 950,000 to 1,050,000 Ω is a good ±5% part. A 5-band ±1% part should read 990,000 to 1,010,000 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 1 MΩ in a pile?
Practise reading it, and its look-alikes, in the resistor challenge.
Try the resistor challenge1 MΩ resistor FAQ
What resistor do I need for a touch button with CapacitiveSensor?
About 1 MΩ when the pad must be touched; the library's guide uses 10 MΩ and more to sense a hand from a distance. Taking about 100 pF for a hand, the time constant is 1 MΩ × 100 pF = 0.1 ms, and the delay the library measures is of that size.
What is the SMD code for a 1 MΩ resistor?
105 on 3-digit parts, 1004 on 4-digit parts, or 01E on EIA-96 parts (01 means 100, E means ×10,000).
What are the 5-band colors for 1 MΩ?
Brown, Black, Black, Yellow, Brown: 100 × 10,000 = 1 MΩ with ±1% tolerance, so 990,000 to 1,010,000 Ω.
How do I tell 1 MΩ from 100 kΩ?
Only the third band differs: green (×100,000) on 1 MΩ, yellow (×10,000) on 100 kΩ. Measure if you are unsure: 1 MΩ reads 950,000 to 1,050,000 Ω, 100 kΩ reads 95 to 105 kΩ.
Bands, ranges and codes come from the same engine as the calculator. Last reviewed .