🕷️ Crawler Inspector

[](https://www.omnicalculator.com/) - [Biology](https://www.omnicalculator.com/biology) - [Chemistry](https://www.omnicalculator.com/chemistry) - [Construction](https://www.omnicalculator.com/construction) - [Conversion](https://www.omnicalculator.com/conversion) - [Ecology](https://www.omnicalculator.com/ecology) - [Everyday life](https://www.omnicalculator.com/everyday-life) - [Finance](https://www.omnicalculator.com/finance) - [Food](https://www.omnicalculator.com/food) - [Health](https://www.omnicalculator.com/health) - [Math](https://www.omnicalculator.com/math) - [Physics](https://www.omnicalculator.com/physics) - [Sports](https://www.omnicalculator.com/sports) - [Statistics](https://www.omnicalculator.com/statistics) - [Other](https://www.omnicalculator.com/other) # Parallel Resistor Calculator  Creators Bogna Szyk  Bogna Szyk LinkedIn Bogna is the chief operating officer at Omni Calculator, where she helps keep things running smoothly and ideas moving forward. With a background in civil engineering and a knack for organizing chaos, she brings structure and strategy to everything she does. After hours, you’ll likely find her dancing zouk or crafting the next twist in a D\&D campaign. [See full profile](https://www.omnicalculator.com/authors/bogna-szyk) Check our [editorial policy](https://www.omnicalculator.com/editorial-policies) and Álvaro Díez  Álvaro Díez LinkedIn Álvaro is an eclectic physicist with a strong passion for everything and anything. He got his Bachelor’s in Fundamental Physics from the University of Cantabria (Spain). After doing his Bachelor’s thesis and a year-long internship at CERN, he moved away from particle physics and into Poland. There, he joined Omni, where he’s been creating calculators, leading marketing campaigns, making videos, and, lately, translating our tools to his native language: Spanish. He is the true definition of a jack of all trades; nobody can predict what his next move will be. [See full profile](https://www.omnicalculator.com/authors/alvaro-diez) Check our [editorial policy](https://www.omnicalculator.com/editorial-policies) Reviewers Steven Wooding  Steven Wooding LinkedIn Steven Wooding is a physicist by training with a degree from the University of Surrey specializing in nuclear physics. He loves data analysis and computer programming. He has worked on exciting projects such as environmentally aware radar, using genetic algorithms to tune radar, and building the UK vaccine queue calculator. Steve is now the Editorial Quality Assurance Coordinator here at Omni Calculator, making sure every calculator meets the standards our users expect. In his spare time, he enjoys cycling, photography, wildlife watching, and long walks. [See full profile](https://www.omnicalculator.com/authors/steven-wooding) Check our [editorial policy](https://www.omnicalculator.com/editorial-policies) 407 people find this calculator helpful 407 Table of contents - [Resistors in parallel formula](https://www.omnicalculator.com/physics/parallel-resistor#resistors-in-parallel-formula) - [How to calculate parallel resistance](https://www.omnicalculator.com/physics/parallel-resistor#how-to-calculate-parallel-resistance) - [Other uses of the parallel resistor calculator](https://www.omnicalculator.com/physics/parallel-resistor#other-uses-of-the-parallel-resistor-calculator) - [FAQs](https://www.omnicalculator.com/physics/parallel-resistor#faqs) This parallel resistor calculator is a tool for determining the **equivalent resistance** of a circuit with up to ten resistors in parallel. On the other hand, you can also check out our [series resistor calculator](https://www.omnicalculator.com/physics/series-resistor) if you want to learn about resistors in series. **Prefer watching** over reading? Learn all you need in 90 seconds with this video **we made for you**: [Watch this on YouTube](https://youtu.be/WOzhLjq570I) ## Resistors in parallel formula A parallel circuit is characterized by a **common potential difference** (voltage) across the ends of all resistors. The equivalent resistance for this kind of circuit is calculated according to the following formula: 1 / R \= 1 / R 1 \+ 1 / R 2 \+ … \+ 1 / R n \\footnotesize 1/R = 1/R\_1 + 1/R\_2 + \\ldots + 1/R\_n 1/R\=1/R1​\+1/R2​\+…\+1/Rn​ where: - R R R — Equivalent parallel resistance; and - R 1 R\_1 R1​ , R 2 R\_2 R2​ , ..., R n R\_n Rn​ — Resistances of individual resistors numbered 1 1 1 , 2 2 2 , to n n n . The units of all values are Ohms (symbol: Ω \\small \\Omega Ω). 1 Ohm is defined as the electrical resistance between two points that, when applied with a potential difference of 1 volt, produces a current of 1 ampere. Hence, 1 Ω \= 1 V / 1 A \\small 1\\ \\Omega = 1\\ \\text{V} / 1\\ \\text{A} 1 Ω\=1 V/1 A or, in SI base units, Ω \= kg ⋅ m 2 / ( s 3 ⋅ A 2 ) \\small \\Omega = \\text{kg} \\cdot \\text{m}^2/(\\text{s}^3 \\cdot \\text{A}^2) Ω\=kg⋅m2/(s3⋅A2). The formula for resistors in parallel is similar to the formula for [inductors in parallel](https://www.omnicalculator.com/physics/parallel-inductors). ## How to calculate parallel resistance The parallel resistor calculator has two different calculation options. The first one allows you to calculate the **total resistance equivalent** to a group of individual resistors in parallel. In contrast, the second one allows you to set the desired total resistance of the bunch and **calculate the one missing resistor** value, given the rest. To keep it simple, we only show you a few rows to input numbers, but **new fields will magically appear as you need** them. You can input up to 10 resistors in total. Let's look at an example for the second, slightly more complicated, calculation option: 1. Select `missing resistor` under the *Calculate...* option. 2. Now input the **total resistance** you want your circuit/collection of resistors to have. 3. Start by **introducing the values of the resistors** you already know (new fields will appear as needed). 4. The calculator automatically gives you the **required missing resistor** after each input. Knowing how the parallel resistors arrangement works makes it possible to apply the [current divider rule](https://www.omnicalculator.com/physics/current-divider) in the circuit. ## Other uses of the parallel resistor calculator The principle is the same as when determining capacitance in series or induction in parallel – you can use it for these calculations too. Just remember that the units are not the same\! If you would like to find out the value of power dissipated in the resistor, try the [Ohm's law calculator](https://www.omnicalculator.com/physics/ohms-law) or [resistor wattage calculator](https://www.omnicalculator.com/physics/resistor-wattage). ## FAQs ### How do you calculate two resistors in parallel? To **calculate the equivalent resistance of two resistors in parallel**: 1. Take their reciprocal values. 2. Add these two values together. 3. Take the reciprocal again. For example, if one resistor is 2 Ω and the other is 4 Ω, then the calculation to find the equivalent resistance is: **1 / (1/2 + 1/4) = 1 / (3/4) = 4/3 = 1.33 Ω**. ### Is the voltage the same in a parallel circuit? **Yes**, the voltage across all the components is the same in a parallel circuit, while the current is divided among all of them. ### Why does resistance decrease in parallel? This phenomenon happens because the current has **many more paths** that it could take. Imagine a shop opens up several new check-out tills. The overall resistance to people going through the check-out will decrease as the workload is shared in parallel. ### How do you find an unknown resistor in a parallel circuit? Rearrange the parallel resistor formula **1/R = 1/R₁ + 1/R₂ + … + 1/Rn** in terms of **Rn**, given that you know the desired overall resistance. That gives you **Rn = (1/R - 1/R₁ + 1/R₂ + …)\-1** For example, if you have **R1 = 4 Ω**, **R2 = 2 Ω** and want **R = 1 Ω**, then **R3 = 1 / (1 - 1/4 - 1/2) = 4 Ω**.  Calculate... Resistor 1 (R1) Resistor 2 (R2) You can add up to 10 resistors; fields will appear as needed. ## Results *Input at least one resistor to obtain a result.* Share result Reload calculator Clear all changes Did we solve your problem today? Yes No Check out 57 similar electronics and circuits calculators 💡 Boost converter Breaker size Bridge rectifier We make it count\!  Calculator Categories Biology Chemistry Construction Conversion Ecology Everyday life Finance Food Health Math Physics Sports Statistics Other Discover Omni Press Editorial policiesPartnerships Meet Omni AboutResource libraryCollectionsContactWe're hiring\!

This parallel resistor calculator is a tool for determining the **equivalent resistance** of a circuit with up to ten resistors in parallel. On the other hand, you can also check out our [series resistor calculator](https://www.omnicalculator.com/physics/series-resistor) if you want to learn about resistors in series. **Prefer watching** over reading? Learn all you need in 90 seconds with this video **we made for you**: [Watch this on YouTube](https://youtu.be/WOzhLjq570I) ## Resistors in parallel formula A parallel circuit is characterized by a **common potential difference** (voltage) across the ends of all resistors. The equivalent resistance for this kind of circuit is calculated according to the following formula: 1 / R \= 1 / R 1 \+ 1 / R 2 \+ … \+ 1 / R n \\footnotesize 1/R = 1/R\_1 + 1/R\_2 + \\ldots + 1/R\_n where: - R R — Equivalent parallel resistance; and - R 1 R\_1 , R 2 R\_2 , ..., R n R\_n — Resistances of individual resistors numbered 1 1 , 2 2 , to n n . The units of all values are Ohms (symbol: Ω \\small \\Omega). 1 Ohm is defined as the electrical resistance between two points that, when applied with a potential difference of 1 volt, produces a current of 1 ampere. Hence, 1 Ω \= 1 V / 1 A \\small 1\\ \\Omega = 1\\ \\text{V} / 1\\ \\text{A} or, in SI base units, Ω \= kg ⋅ m 2 / ( s 3 ⋅ A 2 ) \\small \\Omega = \\text{kg} \\cdot \\text{m}^2/(\\text{s}^3 \\cdot \\text{A}^2). The formula for resistors in parallel is similar to the formula for [inductors in parallel](https://www.omnicalculator.com/physics/parallel-inductors). ## How to calculate parallel resistance The parallel resistor calculator has two different calculation options. The first one allows you to calculate the **total resistance equivalent** to a group of individual resistors in parallel. In contrast, the second one allows you to set the desired total resistance of the bunch and **calculate the one missing resistor** value, given the rest. To keep it simple, we only show you a few rows to input numbers, but **new fields will magically appear as you need** them. You can input up to 10 resistors in total. Let's look at an example for the second, slightly more complicated, calculation option: 1. Select `missing resistor` under the *Calculate...* option. 2. Now input the **total resistance** you want your circuit/collection of resistors to have. 3. Start by **introducing the values of the resistors** you already know (new fields will appear as needed). 4. The calculator automatically gives you the **required missing resistor** after each input. Knowing how the parallel resistors arrangement works makes it possible to apply the [current divider rule](https://www.omnicalculator.com/physics/current-divider) in the circuit. ## Other uses of the parallel resistor calculator The principle is the same as when determining capacitance in series or induction in parallel – you can use it for these calculations too. Just remember that the units are not the same\! If you would like to find out the value of power dissipated in the resistor, try the [Ohm's law calculator](https://www.omnicalculator.com/physics/ohms-law) or [resistor wattage calculator](https://www.omnicalculator.com/physics/resistor-wattage). ## FAQs ### How do you calculate two resistors in parallel? To **calculate the equivalent resistance of two resistors in parallel**: 1. Take their reciprocal values. 2. Add these two values together. 3. Take the reciprocal again. For example, if one resistor is 2 Ω and the other is 4 Ω, then the calculation to find the equivalent resistance is: **1 / (1/2 + 1/4) = 1 / (3/4) = 4/3 = 1.33 Ω**. ### Is the voltage the same in a parallel circuit? **Yes**, the voltage across all the components is the same in a parallel circuit, while the current is divided among all of them. ### Why does resistance decrease in parallel? This phenomenon happens because the current has **many more paths** that it could take. Imagine a shop opens up several new check-out tills. The overall resistance to people going through the check-out will decrease as the workload is shared in parallel. ### How do you find an unknown resistor in a parallel circuit? Rearrange the parallel resistor formula **1/R = 1/R₁ + 1/R₂ + … + 1/Rn** in terms of **Rn**, given that you know the desired overall resistance. That gives you **Rn = (1/R - 1/R₁ + 1/R₂ + …)\-1** For example, if you have **R1 = 4 Ω**, **R2 = 2 Ω** and want **R = 1 Ω**, then **R3 = 1 / (1 - 1/4 - 1/2) = 4 Ω**.