1Brown-Black-Red-Gold (1kΩ)
Inputs
Band 1Brown (1)
Band 2Black (0)
Band 3Red (×100)
ToleranceGold (±5%)
Result
Resistance1,000Ω (1kΩ)
Range950Ω – 1,050Ω
(1×10 + 0) × 100 = 1,000Ω. ±5% = 950–1,050Ω.
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Resistor Calculator
Resistance
1kΩ
Tolerance
±5%
Resistance Value
1kΩ
Min
950Ω
Max
1.1kΩ
What You'll Need
BOJACK 1000 Pcs 25 Values Resistor Kit 1 Ohm-1M Ohm with 5% 1/4W Carbon Film Resistors Assortment
$9.99
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LuminologyPro 1000-Piece Resistor Kit, 25-Value 1/4W ±1% Metal Film, 1Ω-1MΩ
$6.49
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BOJACK 50 Values 1350 Pcs Resistor Kit 0 Ohm-5.6M Ohm with 1% 1/4W Metal Film Resistors Assortment
$12.99
View on AmazonBOJACK 1000 Pcs 25 Values Resistor Kit 1 Ohm-1M Ohm with 5% 1/4W Carbon Film Resistors Assortment
$9.99
View on AmazonLuminologyPro 1000-Piece Resistor Kit, 25-Value 1/4W ±1% Metal Film, 1Ω-1MΩ
$6.49
View on AmazonBOJACK 50 Values 1350 Pcs Resistor Kit 0 Ohm-5.6M Ohm with 1% 1/4W Metal Film Resistors Assortment
$12.99
View on AmazonAs an Amazon Associate, we earn from qualifying purchases.
Price as of Jul 24, 2026. Product prices and availability are accurate as of the date indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
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Example Calculations
2LED Resistor: 5V supply, 20mA
Inputs
Voltage5V
Current0.02A (20mA)
Result
Resistance250Ω
Power100mW
R = 5 / 0.02 = 250Ω. P = 5 × 0.02 = 0.1W. Use 270Ω (next E24 value) rated 1/4W.
Frequently Asked Questions
QHow do I read resistor color bands?
A 4-band resistor: Band 1 = first digit, Band 2 = second digit, Band 3 = multiplier (number of zeros), Band 4 = tolerance. Brown-Black-Red-Gold = 10 × 100 = 1kΩ ±5%.
- Band 1: first significant digit (0–9)
- Band 2: second significant digit (0–9)
- Band 3: multiplier (1 to 1,000,000,000)
- Band 4: tolerance (Gold = 5%, Silver = 10%)
| Color | Digit | Multiplier | Tolerance |
|---|---|---|---|
| Brown | 1 | ×10 | ±1% |
| Red | 2 | ×100 | ±2% |
| Orange | 3 | ×1k | — |
| Yellow | 4 | ×10k | — |
| Green | 5 | ×100k | ±0.5% |
QHow do I calculate resistance from voltage and current?
Ohm's Law: R = V / I. If you need 20mA through an LED with 5V supply and 2V LED forward voltage: R = (5-2) / 0.02 = 150Ω.
- R = V / I (voltage divided by current)
- P = V × I (power dissipated in watts)
- LED resistor: R = (Vsupply - Vled) / Iled
- Always check power rating: P = I² × R
QWhat tolerance should I choose?
For most hobby projects, 5% (gold band) is fine. Precision circuits (audio, measurement) need 1% (brown band). 10% (silver) resistors are cheap but imprecise.
- 20% (no band): very imprecise, avoid
- 10% (silver): basic circuits, LED current limiting
- 5% (gold): most common, good for general use
- 1% (brown): precision analog circuits
QWhat happens if I use the wrong resistor?
Too low resistance = too much current, can burn components. Too high resistance = insufficient current, circuit may not work. Always calculate before installing.
- Too low: excess current, overheating, component damage
- Too high: LED too dim, circuit malfunction
- Exceeded power rating: resistor overheats and fails
- When in doubt, use the next higher standard value
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Last Updated: Jul 24, 2026
This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.