VoltCal Electrical Calculator

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Content rating
Everyone
100+
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Content rating
Everyone
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About this app

VoltCal is a free toolkit of electrical engineering calculators built for practicing engineers, designers, and students. No login or sign-up needed. Open a calculator, enter your inputs, and get results with the standard clauses and assumptions shown.

WHAT'S INSIDE

Power system studies
- Short-circuit calculation (IEC 60909 and ANSI/IEEE C37)
- Protection relay coordination with a time-current curve chart
- Harmonic filter sizing (IEEE 519, IEC 61000-3-2)
- Insulation coordination (IEC 60071-2)
- Motor acceleration and starting voltage dip

Cables and distribution
- LV and MV cable sizing: ampacity, voltage drop, and short-circuit withstand
- Cable schedule and material take-off (MTO) generator
- Cable tray fill and conduit fill
- Busbar sizing
- LV panel board distribution schedule

Protection, earthing, and safety
- Earthing and grounding design (IEEE 80)
- Lightning protection risk assessment and LPS design (IEC 62305)
- Hazardous area classification and Ex equipment selection (IEC 60079)
- IP code reference and compliance check (IEC 60529)

Power supply and facilities
- AC UPS and DC UPS (battery and charger) sizing
- CT and PT/VT instrument transformer sizing
- Electrical room heat load and battery room ventilation
- HV motor efficiency classification (IEC 60034-30-3)
- Solar PV suite: string, inverter, battery bank, DC cable, and protection sizing

FEATURES
- Calculations follow published IEC, IEEE, NEC, and other standards, with the references shown
- Export professional PDF reports (and Excel for schedules)
- Works on phone and tablet
- Free to use, supported by ads

WHO IT'S FOR
Electrical engineers in oil and gas, data centers, industrial plants, utilities, and EPC projects, plus consultants, contractors, and engineering students.

IMPORTANT
Results are for design guidance and preliminary sizing. Always verify critical designs against the applicable standards and project specifications, and have them reviewed by a qualified engineer before use.

Have a suggestion or found an issue? Use the in-app feedback form.
Free electrical engineering calculators: cable, short-circuit, UPS, earthing
Updated on
Sep 29, 2026

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
  • This app may share these data types with third parties
    Location, App activity, and App info and performance
  • This app may collect these data types
    Location, Personal info and 4 others
  • Data is encrypted in transit

What’s new

Fixed mobile menu overlap, improved ad loading, PDF download and back button fixes
Content rating
Everyone
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App support

About the developer
SUNNY ENTERPRISE
sunnyenterprise.dev@gmail.com
60/1, Sunny Enterprise, Mahendra Bhattacharjee Road Howrah, West Bengal 711104 India
+91 83739 42802

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