LED Series Resistor Calculator
Estimate a series LED resistor, its dissipation and a rounded-up E12 reference resistance for low-voltage DC.
LED Series Resistor Calculator User manual
- Fill in the parameters or select the file according to the form, and check the unit and format first.
- A 5 V supply, one LED with a 2 V forward drop and a 10 mA target current require an ideal 300 Ω resistor.
- Click the processing button to view the results, you can copy or download and save.
Calculation method and processing rules
Subtract the combined LED forward voltage from the supply voltage, then divide by the target current. Round upward to an E12 value.
scope of use
Limited to educational calculations at 48 V DC or below. Forward voltage varies with current and temperature. No mains wiring instructions are provided.
Will the input content be saved on the server?
This tool handles input in the browser, and does not upload files or form content. Typing practice scores are only saved in the native browser.
Why may the result be different from other tools?
Limited to educational calculations at 48 V DC or below. Forward voltage varies with current and temperature. No mains wiring instructions are provided. Please compare the input unit, rounding method, applicable rules and data version first.