7 Best Cable Sizing Calculators Compared [2026]

Choosing cable sizing software is a decision that affects every project you deliver. The wrong tool means manual workarounds, standard coverage gaps, or paying for features you never use. The right tool fits your standards, your workflow, and your budget.

This comparison covers the seven most-used cable sizing tools in 2026, tested against real-world criteria that matter to practising engineers: standards coverage, calculation accuracy, report quality, pricing, and offline capability.

Quick Comparison Table

1. ECalPro

Best for: Engineers who work across multiple international standards or need offline capability.

ECalPro covers AS/NZS 3008, BS 7671, IEC 60364, and NEC in a single platform — the only tool that supports all four major cable sizing standards. The free tier includes all 27 calculators with 5 calculations per day and watermarked reports.

Strengths:

• Only platform covering AS/NZS + BS + IEC + NEC simultaneously
• Offline PWA works without internet (useful for site work)
• 23-language interface with localised units
• PPP pricing in 42 countries makes it accessible globally
• Team RBAC with 4 roles and shared projects
• 24,000+ automated tests across 5 verification layers

Weaknesses:

• No LV network design or single-line diagram generation
• No manufacturer protective device database
• Arc flash limited to IEEE 1584 (no DC arc flash)
• No AutoCAD/DWG export
• Free tier capped at 5 calculations per day
• Newer platform — less market track record than established competitors

Pricing: Free tier (all calculators, watermarked reports) | Professional $29/mo | Team $69/mo | Enterprise custom

2. jCalc.net

Best for: Australian engineers who work exclusively within AS/NZS standards.

jCalc has been serving the Australian market for years and has a focused, reliable set of AS/NZS calculators. It does one jurisdiction well.

Strengths:

• Well-established in the Australian market with strong AS/NZS 3008 coverage
• Battery and UPS sizing calculator (uncommon feature)
• Unlimited calculations on paid plans
• Dedicated motor, transformer, and generator calculators refined for Australian practice
• Ralph Lee arc flash method for quick field assessments

Weaknesses:

• AS/NZS only — no BS 7671, IEC 60364, or NEC support
• No free tier (A$265/yr minimum)
• No offline mode
• English only
• No team collaboration features
• No mobile app

Pricing: A$265/year (single plan, no free tier)

3. ELEK Cable Pro

Best for: Engineering firms needing LV network design with protection coordination and manufacturer device data.

ELEK is the most feature-rich tool for engineers who need network-level design capabilities beyond individual cable sizing calculations. The Professional tier includes single-line diagram generation and AutoCAD export.

Strengths:

• LV network design with SLD generation (Professional tier)
• 20,000+ manufacturer protective device database
• 5 arc flash methods including DC arc flash
• AutoCAD/DWG export
• Cable schedule Excel export
• Protection coordination with time-current curve overlays
• Live chat support from qualified engineers
• CIGRE TB 880 validation documentation

Weaknesses:

• No NEC support
• Professional features locked behind A$650/yr tier
• MV cable sizing not available (LV only)
• Requires internet connection for licensing
• No PWA or offline capability
• Complex tiered pricing structure

Pricing: Free tier (6 calcs/day) | Essential A$99/yr | Premium A$290/yr | Professional A$650/yr

4. ElectricalOM (myCableEngineering)

Best for: UK and international engineers focused on BS 7671 and IEC 60364.

ElectricalOM (formerly myCableEngineering) is a Nexans-backed tool with strong BS 7671 implementation. It serves the UK market well but lacks AS/NZS and NEC support.

Strengths:

• Strong BS 7671 implementation with Amendment 2 support
• IEC 60364 coverage for international projects
• Backed by Nexans (cable manufacturer) — deep cable data
• Free tier with basic calculations
• Clean, focused interface for BS 7671 workflow

Weaknesses:

• No AS/NZS 3008 support
• No NEC support
• English only
• No offline mode
• Limited calculator types compared to multi-discipline tools
• No team collaboration features
• No arc flash calculation

Pricing: Free (limited) | Premium pricing varies

5. ClearCalcs

Best for: Multi-discipline engineering firms (structural + electrical + mechanical) that want one platform.

ClearCalcs is primarily a structural engineering tool that has expanded into electrical calculations. Its electrical module is functional but less specialised than dedicated electrical tools.

Strengths:

• Multi-discipline: structural, electrical, and mechanical in one platform
• Good report formatting and professional output
• Team collaboration features built in
• Growing library of calculation templates
• Modern, well-designed interface

Weaknesses:

• Electrical is a secondary focus — less depth than dedicated tools
• No AS/NZS 3008 cable sizing (Australian standard)
• No BS 7671 or IEC 60364 support
• No arc flash or fault calculations
• No offline capability
• Higher price point for electrical-only users
• No free tier

Pricing: From $49/month (varies by discipline and team size)

6. PowerCalc

Best for: US-based engineers working exclusively with NEC.

PowerCalc focuses on NEC compliance and serves the US market. If you only work within NEC/NFPA 70, it does the job. It cannot help with international projects.

Strengths:

• Strong NEC/NFPA 70 implementation
• Focused on US electrical practice and terminology
• Panel schedule and load calculation tools
• Integration with US-market workflows

Weaknesses:

• NEC only — no international standards
• No AS/NZS, BS 7671, or IEC 60364 support
• No offline mode
• English only
• No free tier
• Limited calculator types

Pricing: From $29/month

7. Excel Spreadsheets

Best for: One-off custom calculations, preliminary estimates, or proprietary manufacturer-specific calculations that no standard tool covers.

Excel remains the most-used "tool" for cable sizing, though calling it a tool is generous — it is really a collection of templates of varying quality, maintained by individual engineers.

Strengths:

• Maximum flexibility for custom calculations
• Works offline
• No recurring subscription cost
• Familiar interface for every engineer
• Good for preliminary estimates and data post-processing

Weaknesses:

• 88% of spreadsheets contain errors (Panko research)
• No automatic standard updates when codes change
• No built-in input validation
• No audit trail
• Version control is a nightmare (Cable_Sizing_FINAL_v3_UPDATED.xlsx)
• Every firm maintains different templates of unknown quality
• Manual table lookups are error-prone
• No professional report output without significant formatting effort

Pricing: "Free" (but the engineering time to maintain and verify templates is substantial)

Standards Coverage Matrix

This is the most important differentiator. If your standard is not supported, nothing else matters.

Pricing Comparison (Annual Cost)

Which Tool Should You Choose?

Choose ECalPro if you work across multiple standards (especially if NEC + BS/IEC), need offline site calculations, work in a multilingual team, or want a free starting point to evaluate before committing.

Choose jCalc if you work exclusively in Australia within AS/NZS standards, need battery sizing, and prefer an established platform with a long track record in the Australian market.

Choose ELEK Cable Pro if you need LV network design with SLD generation, protection coordination with real manufacturer devices, multi-method arc flash analysis, or AutoCAD export. ELEK is the power tool for complex network-level design work.

Choose ElectricalOM if you work primarily in the UK with BS 7671 and want a focused, Nexans-backed tool with strong cable data.

Choose ClearCalcs if you are a multi-discipline firm that wants structural, electrical, and mechanical calculations in one platform and does not need deep electrical specialisation.

Choose PowerCalc if you work exclusively in the US with NEC and need focused NEC compliance tools with panel schedule features.

Choose Excel if you have proprietary or highly custom calculations that no standard tool supports, or you need maximum flexibility for one-off analysis.

Frequently Asked Questions

Is free cable sizing software accurate enough for professional use?

Free tiers from ECalPro and ELEK Cable Pro use the same calculation engine as their paid tiers — the results are identical. The limitations on free tiers are typically report branding (watermarks), daily calculation caps, and team features. The calculations themselves are not degraded. Always verify any tool against a known reference result before trusting it on a real project.

Can I use one tool for all international standards?

ECalPro is currently the only tool that covers AS/NZS 3008, BS 7671, IEC 60364, and NEC in a single platform. Other tools cover 1-3 standards. If you regularly work across multiple jurisdictions, this eliminates the need to maintain expertise in multiple tools.

What is the biggest risk with cable sizing spreadsheets?

Silent errors — results that look reasonable but are wrong. A broken VLOOKUP returning the wrong column, a hardcoded derating factor that should reference a different table, or a formula referencing the old edition of a standard. Purpose-built calculators eliminate these risks because the standard tables are coded once, verified, and tested automatically.

Do any cable sizing tools work offline?

ECalPro is the only cloud-based cable sizing tool with true offline capability via its Progressive Web App. Calculations run locally in the browser and sync when connectivity returns. Excel works offline but carries all the risks discussed above. ELEK has a desktop app that requires internet for licensing.

How important are automated tests in a cable sizing tool?

Very important, though most users never see them. ECalPro runs 24,000+ automated tests across 5 verification layers on every release. ELEK publishes 1,100+ per release. These tests verify that every standard table, every derating factor, and every calculation path produces correct results. A tool without comprehensive automated testing is a tool that may silently break when code changes are made.

Related Resources

• ECalPro vs Excel: Why Engineers Are Moving to Cloud Calculators
• The Complete Cable Sizing Comparison: Every Factor, All Four Standards
• Cable Sizing: The 50m Office Feeder — AS/NZS vs BS 7671 vs IEC vs NEC
• View all calculators