Calculate the correct series resistor needed to safely power light-emitting diodes. Input supply voltage, LED voltage drop, current, and the number of LEDs to find the required resistor value and wattage.






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If you already know LED Resistor Calculator Plus, this is the deeper bench. 250+ led resistor calculator plus apps for iPhone, all reviewed and ranked by user rating, recency, and download trend as of September 2026.
| # | App | Price | Rating | Ads | In-App Purchases | Updated | |
|---|---|---|---|---|---|---|---|
| 1 | $2.99 | 4.8★ (8) | No | No | Sep 2026 | ||
| 2 | Free | 3.6★ (27) | Yes | No | Jun 2026 | ||
| 3 | Free | 4.9★ (60) | No | No | Sep 2026 | ||
| 4 | $0.99 | — | — | No | May 2026 | ||
| 5 | Free | 1.0★ (1) | Yes | No | May 2026 | ||
| 6 | Free | — | No | No | Aug 2026 | ||
| 7 | Free | 4.0★ (1) | No | No | May 2026 | ||
| 8 | $2.99 | — | No | No | Aug 2026 |






Calculate the correct series resistor needed to safely power light-emitting diodes. Input supply voltage, LED voltage drop, current, and the number of LEDs to find the required resistor value and wattage.


Easily determine the resistance value of electronic components using their color bands. This reference tool supports both 4 and 5-band resistors, making it ideal for makers, engineers, and students working with electronics projects.




Easily determine the resistance value of electronic components. Simply select the number of color bands on your resistor and input the colors one by one to instantly get the resistance and tolerance. This tool simplifies a common electronics task.