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PLAN YOUR ELECTRICAL LOAD

Electrical Calculator HUB

Calculate voltage drop, wire size, breaker sizing, conduit fill, and electrical loads with contractor-friendly tools built for real projects.

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Choose an Electrical Tool

Select the calculator that matches your project. Each tool is designed for practical electrical estimating, planning, and field use.

Voltage Drop Calculator

Check voltage drop for long wire runs and see when upsizing conductors may be recommended.

Wire Size Calculator

Estimate the right wire size based on amps, distance, voltage, and conductor type.

Breaker Size Calculator

Find a recommended breaker size based on electrical load and standard sizing logic.

Watts / Volts / Amps Calculator

Quickly calculate watts, volts, or amps when you know any two values.

Conduit Fill Calculator

Estimate conduit fill and plan wire runs more efficiently.

Electrical Load Calculator

Estimate total load for circuits, equipment, or service planning.

Voltage Drop Calculator

Calculate voltage drop for branch circuits, feeders, outdoor runs, and long-distance wiring. Enter voltage, current, wire length, wire size, and conductor material to estimate voltage loss and determine whether a larger conductor may be needed.

Calculator inputs
  • Voltage
  • Amps
  • One-way distance
  • Wire material
  • Wire size
  • Phase (optional)
  • Circuit type (optional)
Outputs
  • Voltage drop
  • Percentage drop
  • Suggested status: Acceptable / Caution / Consider larger wire

Example: 120V, 20A, 150 ft copper run → X% voltage drop

Wire Size Calculator

Estimate a suitable wire size based on amperage, voltage, distance, and conductor material. This tool helps with branch circuits, feeders, and general electrical planning.

Inputs
  • Amps
  • Voltage
  • Copper / aluminum
  • Distance
  • Installation type (optional)
Outputs
  • Suggested wire size
  • Ampacity note
  • Voltage drop reminder

Example: 40A, 240V, 100 ft copper → suggested wire size

Breaker Size Calculator

Calculate a recommended breaker size using the connected load and standard breaker sizing logic. Useful for appliances, HVAC, subpanels, and dedicated circuits.

Inputs
  • Amps or watts
  • Voltage
  • Continuous load (Yes/No)
Outputs
  • Minimum breaker size
  • Next standard breaker size
  • Caution if oversized/undersized

Example: 32A continuous load → recommended breaker size

Watts / Volts / Amps Calculator

Quickly calculate watts, volts, or amps using the values you already know. Useful for appliances, lighting, equipment, and general electrical troubleshooting.

Inputs
  • Choose solve for: watts / volts / amps
  • Enter remaining values
Outputs
  • Solved value
  • Formula shown

Example: 1500 watts at 120 volts = 12.5 amps

Inputs
  • Conduit size
  • Conduit type
  • Wire size
  • Wire count

Conduit Fill Calculator

Estimate conduit fill based on conduit size, wire type, and wire quantity. Useful for electricians planning cleaner, code-aware conduit runs.

Example: 3/4 inch conduit with X conductors = fill percentage

Outputs
  • Fill percentage
  • Within range / Caution

Electrical Load Calculator

Estimate electrical load for circuits, equipment, rooms, or renovation planning. Useful for panel upgrades, additions, workshops, garages, and large appliances.

Inputs
  • Appliance / equipment loads
  • Lighting load
  • Square footage (optional)
  • Voltage
Outputs
  • Estimated total load
  • Service / circuit note
  • Panel upgrade suggestion (if needed)

Example: Garage subpanel with lighting and tools = estimated load

Download the Mobile ELECTRICAL CALCULATOR App

Get professional estimation tools for on-the-go power planning and breaker sizing. Our app helps you calculate amperage, voltage, and circuit loads while you are working in the field.

Take your electrical calculator to the jobsite for instant planning on any mobile.

Fluke 87-5 Industrial Multimeter Kit

Professional-grade multimeter kit used for advanced electrical diagnostics, voltage measurement, and troubleshooting.

Fluke Networks Heavy Duty Wire Strippers

Precision wire stripping tool designed for clean, accurate conductor preparation.

Recommended Electrical Tools for Your Project

Based on your calculation, these are professional tools commonly used for electrical testing, circuit setup, and installation.

Fluke 179 True-RMS Digital Multimeter

High-accuracy multimeter for measuring voltage, current, resistance, and temperature in electrical systems.

Advanced Wire Tracer Kit

Used for locating wires, identifying circuits, and troubleshooting hidden electrical runs.

Fluke 117 Multimeter + Clamp Meter Kit

Complete electrician testing kit for measuring current, voltage, and diagnosing circuit performance.

Professional Fish Tape Wire Puller

Essential tool for pulling wire through conduit, walls, and tight installation spaces.

Calculator FAQ

HOW DO I CALCULATE VOLTAGE DROP?

Voltage drop depends on voltage, current, wire size, conductor material, and distance. Use the Voltage Drop Calculator: enter voltage, amps, one-way length, wire size, and material to see an estimated drop and whether you may need a larger conductor.

WHAT WIRE SIZE DO I NEED FOR A 50 AMP CIRCUIT?

Wire size depends on amp rating, conductor material, installation conditions, and local code. As a rough planning guide, many 50A copper circuits use wire in the 6–8 AWG range, but final sizing must follow code tables and a licensed electrician’s judgment.

HOW DO I SIZE A BREAKER?

Start from the load in amps. For continuous loads, multiply by 1.25, then choose the next standard breaker size above that value. Always confirm with local code and manufacturer instructions before final selection.

WHAT IS THE 80% RULE FOR CONTINUOUS LOADS?

Many codes limit continuous loads to 80% of a breaker’s rating. That means a continuous load should be no more than 16A on a 20A breaker, or 24A on a 30A breaker. This is planning guidance only—always verify with local requirements.

HOW MANY WATTS IS 15 AMPS AT 120 VOLTS?

Watts = volts × amps. A 15A load at 120V is about 1,800 watts. For continuous loads, you may want to plan around 80% of that value.

HOW DO I CALCULATE CONDUIT FILL?

Conduit fill depends on conduit size, type, and the outside diameter of all conductors. Use the Conduit Fill Calculator as a planning tool, then confirm with code conduit-fill tables.

WHEN SHOULD I UPSIZE WIRE?

You may consider upsizing when voltage drop is high, distances are long, or installation conditions reduce ampacity. Upsizing should always be checked against code tables and approved by a licensed electrician.

DO I NEED A LICENSED ELECTRICIAN?

For most new circuits, service changes, and code-regulated work, a licensed electrician and inspections are required. This calculator is for planning only and does not replace professional design or code approval.

HOW DO I ESTIMATE MY TOTAL AMP LOAD?

Add up the watts for your loads and divide by the system voltage to get amps. For mixed circuits or panels, use the Electrical Load Calculator as a planning guide, then verify with an electrician or engineered calculation.

WILL DISTANCE IMPACT WIRE SELECTION?

Yes. Longer runs increase voltage drop, which may require a larger conductor to keep voltage within acceptable limits. Use the Voltage Drop Calculator to compare options and then confirm with code tables.

WHAT VOLTAGE SHOULD I USE FOR PLANNING?

Use the nominal system voltage you expect in service, such as 120V, 240V, or 208V. For detailed design, always confirm actual system voltage and local code requirements.

IMPORTANT NOTICE

All results from this Electrical Calculator are for estimation and planning only. Final wire sizing, breaker selection, load calculations, and electrical design must follow applicable codes and be reviewed by a licensed electrician and local authority having jurisdiction.

Project Planning Ideas

Estimating loads for a house kitchen

Planning power for an electric car

Drafting sub-panel circuit layouts

Estimating wire needs for full basement renovations

More Planning Tools

Amperage Calc
Ohm's Law Calc
Wire Gauge Tool
Conduit Capacity
Voltage Drop Tool

Planning & Data Tools

Current Load

Estimate specific amperage for home circuits to help you plan for appropriate breaker and panel capacities.

Phase Selection

Identify potential power requirements for heavy equipment, accounting for single or three-phase estimations.

Wire Gauging

Predict wiring needs by calculating estimated distances and voltage drop for copper or aluminum conductors.

Panel Board Planning

Evaluate service demand against panel limits to help design a safer and more durable electrical foundation.

How the Electrical Calc Helps

01

Choose Category

Pick between load, amperage, or wire sizing tools to start your specific electrical project.

02

Provide Your Data

Enter voltage, current, and run length into the electrical calculator for a detailed load estimate.

03

Check Drafts

Review estimated wattage and wire types immediately to help guide your initial project planning.

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