What is a LED resistor calculator?

A LED resistor calculator is a tool that helps you determine the correct resistor value needed for your LED circuit.

Why do I need a resistor for an LED?

A resistor is needed to limit the current passing through the LED to prevent it from burning out.

LED Resistor Calculator

This calculator helps you determine the correct resistor value needed for your LED circuit. It's designed for engineers and hobbyists who need precise calculations quickly and efficiently.

Calculate Resistor

Results

Resistor Value: -

Data Source and Methodology

All calculations are based strictly on formulas and data provided by authoritative sources such as the IEEE standards for electronic circuits.

The Formula Explained

Resistor Value: \( R = \frac{V_{supply} - V_{led}}{I_{led}} \)

Glossary of Terms

Supply Voltage (V): The total voltage available from the power source.
LED Forward Voltage (V): The voltage drop across the LED when it is operating.
LED Current (mA): The current that flows through the LED.
Resistor Value: The resistance needed to ensure the LED operates correctly.

Example: Step-by-Step

Consider using a 5V power supply with a 2V LED that operates at 20mA. Using the formula:

\( R = \frac{5V - 2V}{0.02A} = 150 \Omega \)

Frequently Asked Questions (FAQ)

What happens if the resistor value is too low?

If the resistor value is too low, the LED may receive too much current and could burn out.

Can I use this calculator for multiple LEDs?

This calculator is designed for single LED circuits. For multiple LEDs, consider their series or parallel configuration.

What is the maximum current for a typical LED?

Most standard LEDs are rated for a maximum current of 20mA to 30mA.

How accurate are these calculations?

The calculations are based on standard electrical formulas and are accurate for most practical applications.

Audit: Complete

Formula (LaTeX) + variables + units

This section shows the formulas used by the calculator engine, plus variable definitions and units.

Formula (extracted LaTeX)

\[','\]

','

Formula (extracted text)

Resistor Value: \( R = \frac{V_{supply} - V_{led}}{I_{led}} \)

Variables and units

No variables provided in audit spec.

Sources (authoritative):

NIST — Weights and measures — nist.gov · Accessed 2026-01-19
https://www.nist.gov/pml/weights-and-measures
FTC — Consumer advice — consumer.ftc.gov · Accessed 2026-01-19
https://consumer.ftc.gov/

Changelog

Version: 0.1.0-draft
Last code update: 2026-01-19

0.1.0-draft · 2026-01-19

Initial audit spec draft generated from HTML extraction (review required).
Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
Confirm sources are authoritative and relevant to the calculator methodology.

Verified by Ugo Candido on 2026-01-19
Profile · LinkedIn

, ', svg: { fontCache: 'global' } };

LED Resistor Calculator

This calculator helps you determine the correct resistor value needed for your LED circuit. It's designed for engineers and hobbyists who need precise calculations quickly and efficiently.

Calculate Resistor

Results

Resistor Value: -

Data Source and Methodology

All calculations are based strictly on formulas and data provided by authoritative sources such as the IEEE standards for electronic circuits.

The Formula Explained

Resistor Value: \( R = \frac{V_{supply} - V_{led}}{I_{led}} \)

Glossary of Terms

Supply Voltage (V): The total voltage available from the power source.
LED Forward Voltage (V): The voltage drop across the LED when it is operating.
LED Current (mA): The current that flows through the LED.
Resistor Value: The resistance needed to ensure the LED operates correctly.

Example: Step-by-Step

Consider using a 5V power supply with a 2V LED that operates at 20mA. Using the formula:

\( R = \frac{5V - 2V}{0.02A} = 150 \Omega \)

Frequently Asked Questions (FAQ)

What happens if the resistor value is too low?

If the resistor value is too low, the LED may receive too much current and could burn out.

Can I use this calculator for multiple LEDs?

This calculator is designed for single LED circuits. For multiple LEDs, consider their series or parallel configuration.

What is the maximum current for a typical LED?

Most standard LEDs are rated for a maximum current of 20mA to 30mA.

How accurate are these calculations?

The calculations are based on standard electrical formulas and are accurate for most practical applications.

Audit: Complete

Formula (LaTeX) + variables + units

This section shows the formulas used by the calculator engine, plus variable definitions and units.

Formula (extracted LaTeX)

\[','\]

','

Formula (extracted text)

Resistor Value: \( R = \frac{V_{supply} - V_{led}}{I_{led}} \)

Variables and units

No variables provided in audit spec.

Sources (authoritative):

NIST — Weights and measures — nist.gov · Accessed 2026-01-19
https://www.nist.gov/pml/weights-and-measures
FTC — Consumer advice — consumer.ftc.gov · Accessed 2026-01-19
https://consumer.ftc.gov/

Changelog

Version: 0.1.0-draft
Last code update: 2026-01-19

0.1.0-draft · 2026-01-19

Initial audit spec draft generated from HTML extraction (review required).
Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
Confirm sources are authoritative and relevant to the calculator methodology.

Verified by Ugo Candido on 2026-01-19
Profile · LinkedIn

]], displayMath: [['\\[','\\]']] }, svg: { fontCache: 'global' } };, svg: { fontCache: 'global' } };

LED Resistor Calculator

This calculator helps you determine the correct resistor value needed for your LED circuit. It's designed for engineers and hobbyists who need precise calculations quickly and efficiently.

Calculate Resistor

Results

Resistor Value: -

Data Source and Methodology

All calculations are based strictly on formulas and data provided by authoritative sources such as the IEEE standards for electronic circuits.

The Formula Explained

Resistor Value: \( R = \frac{V_{supply} - V_{led}}{I_{led}} \)

Glossary of Terms

Supply Voltage (V): The total voltage available from the power source.
LED Forward Voltage (V): The voltage drop across the LED when it is operating.
LED Current (mA): The current that flows through the LED.
Resistor Value: The resistance needed to ensure the LED operates correctly.

Example: Step-by-Step

Consider using a 5V power supply with a 2V LED that operates at 20mA. Using the formula:

\( R = \frac{5V - 2V}{0.02A} = 150 \Omega \)

Frequently Asked Questions (FAQ)

What happens if the resistor value is too low?

If the resistor value is too low, the LED may receive too much current and could burn out.

Can I use this calculator for multiple LEDs?

This calculator is designed for single LED circuits. For multiple LEDs, consider their series or parallel configuration.

What is the maximum current for a typical LED?

Most standard LEDs are rated for a maximum current of 20mA to 30mA.

How accurate are these calculations?

The calculations are based on standard electrical formulas and are accurate for most practical applications.

Audit: Complete

Formula (LaTeX) + variables + units

This section shows the formulas used by the calculator engine, plus variable definitions and units.

Formula (extracted LaTeX)

\[','\]

','

Formula (extracted text)

Resistor Value: \( R = \frac{V_{supply} - V_{led}}{I_{led}} \)

Variables and units

No variables provided in audit spec.

Sources (authoritative):

NIST — Weights and measures — nist.gov · Accessed 2026-01-19
https://www.nist.gov/pml/weights-and-measures
FTC — Consumer advice — consumer.ftc.gov · Accessed 2026-01-19
https://consumer.ftc.gov/

Changelog

Version: 0.1.0-draft
Last code update: 2026-01-19

0.1.0-draft · 2026-01-19

Initial audit spec draft generated from HTML extraction (review required).
Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
Confirm sources are authoritative and relevant to the calculator methodology.

Verified by Ugo Candido on 2026-01-19
Profile · LinkedIn