How to Use Conduit Calculator Pro

Branch Circuit Wire Size Calculator

What conductor size coordinates ampacity and voltage drop?

1. Confirm that the common-circuit scope matches the project; specialized loads and neutral rules remain outside this workflow.
2. Choose the system, voltage, conductor material, temperature ratings, ambient condition, and current-carrying-conductor count.
3. Separate continuous and noncontinuous amperes, then enter one-way length and the voltage-drop target.
4. Select the actual protective-device rating and wire-type EGC material; the calculator does not select the breaker or fuse.
5. Review the ampacity minimum, voltage-drop minimum, coordinated conductor, protective-device check, and EGC size.
6. Transfer the circuit conductors and EGC to Conduit Size, then choose exact manufacturer products so published outside diameters are used.

Conduit Fill Calculator

Will these cables fit in the conduit I selected?

1. Choose the conduit type and trade size.
2. Select each cable product and enter its quantity.
3. For an electrical-only project, optionally calculate and include one wire-type equipment grounding conductor using the confirmed protective-device rating and phase-conductor sizes.
4. Confirm the fill criteria and optional bend treatment.
5. Review the PASS or FAIL result and detailed formulas.

Conduit Size Calculator

What conduit sizes are required for my cable load?

1. Select the conduit material and maximum size allowed.
2. Select each cable product and enter its quantity.
3. For an electrical-only project, optionally include a calculated wire-type EGC before reviewing the required conduit size.
4. Confirm the fill criteria and optional bend treatment.
5. Review and apply the recommended conduit plan.

Conduit Cable Capacity Calculator

How many identical cables fit in this conduit?

1. Choose the conduit material and trade size.
2. Select one cable manufacturer and product.
3. Choose the permitted fill criterion.
4. Review the maximum quantity and nearby-size comparison.

Pull Box Size Calculator

What inside box dimensions does my conduit layout require?

1. Choose Power conductors, Communications / low-voltage cable, or Fiber-optic cable. Power uses the NEC 314.28 workflow; Communications and Fiber are manufacturer-data pathway-planning reviews.
2. For Communications or Fiber, you may continue directly with quick planning. When manufacturer data is available, open the optional cable details and enter the governing cable or bundle outside diameter, installation and installed bend radii, total routing clearance, and bend plane.
3. Add each physical conduit once and choose where it enters: the left, right, top, bottom, or back of the enclosure. Back means the mounting surface opposite the cover—not another building wall.
4. In Power mode, the largest 4 AWG–2000 kcmil conductor is optional for each Back entry. Add it when you want the calculator to check front-to-cover depth; otherwise enter the proposed depth and follow the REVIEW note. Partial Back-entry data produces only a provisional depth, and the calculator never assumes a hidden conductor size. Communications and Fiber do not use this field.
5. For example, set Conduit 1 to Left side and 4 inches, set Conduit 2 to Right side and 2 inches, then use Add conduit for each additional 2-inch conduit on the right side.
6. The calculator connects each added conduit to Conduit 1 automatically. Open Advanced routing only if the actual conductors follow a different route or are spliced or tapped in the box.
7. In Power mode, review the automatically identified straight, angle, U-pull, or splice rule. Communications and Fiber quick plans document the layout without assuming a cable radius; completed optional details add the conservative 2R + cable diameter + clearance bend envelope.
8. Review the tracked length, width, and depth targets, then enter or adjust the usable inside dimensions of the specific box you want to verify. Cable modes remain REVIEW with or without the optional envelope because manufacturer and project requirements still govern.
9. Print a branded report, download the diagram or CSV, or copy a shareable calculation link.

Electrical Box Fill Calculator

Does this outlet, device, or junction box have enough usable volume?

1. Confirm that the 2023 NEC 314.16 scope matches the project and that every conductor is 18 AWG through 6 AWG.
2. Enter the usable assembled box volume from the applicable marking, Table 314.16(A) entry, and qualifying marked additions; calculate barrier-separated spaces independently.
3. Group insulated conductors by size, counting entering terminated or spliced conductors and unspliced pass-throughs once. Count an unbroken loop or coil twice only when it is at least twice the minimum free-conductor length required by 300.14.
4. Count equipment grounding conductors that enter the box and identify the largest entering EGC; do not count an equipment bonding jumper that begins and ends within the box.
5. Add ordinary internal cable clamps, luminaire studs, hickeys, device-yoke groups, and terminal-block assemblies where present; for clamps or support fittings, confirm the largest conductor physically present even if it stays entirely inside the box.
6. Review the itemized allowance table and confirm required volume does not exceed available volume; an exact equality passes.
7. Verify conductor permissions, box depth, wire-bending space, listings, installation requirements, local amendments, and AHJ requirements separately.

Voltage Drop Calculator

How much voltage will be lost between the source and load?

1. Choose a preset or select DC two-wire, AC single-phase, or balanced AC three-phase.
2. Enter amperes, watts, kilowatts, VA, or kVA and confirm the calculated load current.
3. Choose a single run or a feeder-plus-branch layout, then enter each one-way length and conductor size.
4. Choose copper or aluminum and set the maximum combined voltage-drop target.
5. When needed, review power factor, reactance, conductor temperature, and parallel-conductor assumptions.
6. Review segment and combined voltage loss, estimated load voltage, maximum length, and the nearby conductor comparison.
7. Print a branded report, download the CSV, or copy a shareable calculation link.

Wire Ampacity Calculator

What ampacity remains after correction, adjustment, and terminal limits?

1. Confirm that the 2023 NEC reference matches the project basis and adopted requirements.
2. Choose copper or aluminum, conductor size, construction, and insulation temperature rating.
3. Enter the lowest applicable marked equipment-terminal temperature rating.
4. Choose Celsius or Fahrenheit for ambient temperature, confirm the displayed equivalent, and enter the code-counted number of current-carrying conductors.
5. Separate continuous and noncontinuous load so the displayed load requirement shows the 125% treatment.
6. Review the table ampacity, both factors, conditions-of-use result, terminal limitation, small-conductor cap when applicable, and governing explanation.
7. Review the minimum passing conductor and nearby-size comparison; select a size to see its calculation details beside the table on desktop or beneath the row on narrower screens.
8. Print or save the branded report, download CSV, copy the share link, or transfer material and size to Voltage Drop.

Cable Tray Fill Calculator

What cable tray width is required for this cable load?

1. Choose generic dimensions or a verified manufacturer tray series.
2. Select cross-sectional area or single-layer width as the documented calculation method.
3. Optionally select an installation allowance. The default is 0%; 20% is recommended for typical field conditions, but the user must choose it.
4. Add each cable product or custom outside diameter and quantity.
5. Review occupied capacity, minimum inside width, and the recommended available width.
6. Verify structural loading, support span, separation, grounding, and the governing installation rules.
7. Print a branded report, download CSV, or copy a shareable link.

Equipment Grounding Conductor Calculator

What wire-type equipment grounding conductor is required?

1. Confirm that the 2023 NEC reference and narrow single-conduit scope match the project basis.
2. Select the overcurrent-device rating and copper or aluminum EGC material.
3. Enter the minimum phase conductor with sufficient ampacity and the final installed phase conductor.
4. Review the base Table 250.122 size, phase-area ratio, proportional required area, and final standard size.
5. Enter the phase-conductor quantity, then transfer the phase and EGC rows to Conduit Fill or Conduit Size.
6. Select an exact listed product for each transferred row and verify the fault-current path, wiring method, special rules, and AHJ requirements.

Conduit Jam Ratio Calculator

Could identical cables jam during this conduit pull?

1. Choose the conduit type and trade size.
2. Select one cable manufacturer and product, or enter a custom round-cable diameter.
3. Enter the number of identical cables; published jam-risk ranges apply at three or more.
4. Review the conduit-fill result and maximum identical-cable capacity first. If the quantity does not fit, increase the conduit size or divide the cables among additional conduits.
5. Then review the jam ratio, published risk range, expected three-cable configuration, and formula. Quantity changes fill but does not change the diameter-based jam ratio.
6. Verify conduit fill, measured cable diameter, bends, pulling tension, sidewall pressure, lubricant, and manufacturer pulling limits.
7. Print a branded report, download CSV, or copy a shareable link.

Conduit Offset and Rolling Offset Calculator

What bend spacing and rotation does my conduit offset require?

1. Choose a standard offset for a one-plane rise or a rolling offset for combined rise and horizontal roll.
2. Choose imperial or metric units and enter the required dimensions.
3. Select the equal bend angle used at both ends of the offset.
4. Review true offset, multiplier, ideal centerline travel, horizontal run, theoretical shrink, and rolling rotation angle when applicable.
5. Use the diagram and formula breakdown to review the geometry.
6. Verify bender take-up, shoe radius, field-marking method, springback, conduit limits, and manufacturer instructions before bending.
7. Print a branded report, download CSV, or copy a shareable link.

3-Point Saddle Bend Calculator

Where do I mark a saddle over a narrow obstruction?

1. Enter the obstruction height and distance to its center.
2. Choose a 45° or 60° center bend.
3. Enter available straight conduit length.
4. Measure all three calculated marks from the same conduit end.
5. Verify the bender center notch, arrow, springback, and actual clearance before bending.

4-Point Saddle Bend Calculator

How do I clear a wider obstruction?

1. Enter obstruction height, clear width, and distance to its start.
2. Choose the equal offset bend angle.
3. Review all four marks, travel, shrink, and occupied mark span.
4. Add practical side clearance where required.
5. Verify the proposed layout with the bender and field obstruction.

90° Conduit Stub-Up Calculator

Where do I mark a 90-degree stub?

1. Enter the desired finished stub height.
2. Choose a matching verified preset or enter the take-up printed on the bender.
3. Measure the arrow mark from the conduit end.
4. Align the bender arrow and bend to the finished 90-degree position.
5. Verify conduit compatibility, springback, and final dimension.

Common features

• Custom cables: select Custom / user-entered under Manufacturer or Custom round cable under Cable product, then enter the outside diameter.
• Electrical power conductors: choose Electrical power conductors, then narrow material, insulation, and solid or stranded construction before choosing the manufacturer and conductor size. The verified Southwire, Encore Wire, and Cerrowire presets supply insulated outside diameter for pathway calculations; verify ampacity and all electrical design requirements separately.
• Optional bend planning allowance: the default NEC fill method applies no automatic bend-based reduction, including for electrical conductors. Select another allowance only when the manufacturer, project specification, authority having jurisdiction, or approved design method requires it.
• Live Results: updates as inputs change and links to the detailed calculation.
• Send to another calculator: compatible result pages can open Conduit Fill, Conduit Size, or Conduit Jam Ratio with the applicable conduit, cable, quantity, and fill inputs already selected. The original calculator remains available and unchanged.
• Asymmetric conduit layouts: add each physical conduit once. New conduits connect to Conduit 1 automatically, and the generated connections remain editable.
• Branded reports: every calculator can create a logo-branded Print / Save PDF report and a CSV with report attribution.
• Project fields: the voltage-drop report can include project name, circuit identifier, preparer, and revision without placing those fields in the shareable URL.
• Pull-box diagrams: download a branded SVG for drawings or a high-resolution PNG for reports and markups.
• Voltage-drop recommendations: conductor recommendations address the selected voltage-drop target only; verify ampacity and every other applicable requirement separately.
• Feeder and branch mode: enter the one-way length and conductor for each segment to see individual and combined voltage loss.
• Load conversion: watts and kilowatts use power factor for AC current conversion; VA and kVA represent apparent power and do not.
• Advanced assumptions: temperature, parallel paths, and reactance scenarios affect the modeled drop but do not verify code-compliant installation details.