Engineering calculators
Tools for the arithmetic that comes up in every test campaign and every installation: correcting a reading for temperature, comparing phases, sizing a battery bank or forecasting how much life it has left, interpreting a dissolved gas analysis, converting the moisture content of an oil, choosing a cable size in mm² or AWG, turning any physical unit into another and knowing the time right now in any country. They all calculate in your browser — no data is sent unless you ask an engineer to review your battery life forecast — and each one states the standard it follows and the instrument that makes the actual measurement.
Insulation resistance calculator: temperature correction, PI and DAR
Correct a megohmmeter reading to 40 °C, calculate PI and DAR and check whether the winding meets the IEEE 43-2000 minimums for its thermal class, winding type, test connection and rating.
Open the calculatorTransformer winding resistance calculator: correction to 75 °C and phase imbalance
For transformers: correct a measured winding resistance to 75 °C, 85 °C or 20 °C and calculate the imbalance between the three phases.
Open the calculatorStationary battery calculator: sizing, autonomy and capacity test
Work out the minimum capacity your load profile demands, the estimated autonomy against a constant current and the result of a discharge test corrected for temperature.
Open the calculatorDissolved gas analysis calculator: Duval triangles and pentagons, IEC 60599 and IEEE
Enter the chromatograph concentrations and get Duval Triangles 1 to 7, the Duval Pentagons, the IEC 60599 ratios, Rogers, Doernenburg, the IEEE C57.104 conditions and the IEEE C57.146 silicone thresholds.
Open the calculatorMoisture in transformer oil calculator: ppm, relative saturation and IEC 60422 classification
Convert the water in an oil between mg/kg and relative saturation at any temperature, find out when free water would appear, and classify the oil according to IEC 60422.
Open the calculatorSF6 calculator: mass, moisture, leaks, recovery and gas quality
SF6 mass, dew point ↔ ppmv, leak rate against IEC 62271-1, recovery times, and acceptance criteria for new (IEC 60376) and used (IEC 60480) SF6.
Open the calculatorBushing tan δ and capacitance calculator
Get the dissipation factor and the capacitance from the bridge reading and compare them against the bushing nameplate values.
Open the calculatorEarthing calculator: soil resistivity, grid, step and touch voltage
Soil resistivity by Wenner or Schlumberger with a two-layer model, resistance of rods, conductors and grids, step and touch voltages to IEEE 80 and ITC-RAT 13, and earthing conductor sizing.
Open the calculatorTransformer loading calculator per IEEE C57.91: hot spot, overload, and loss of life
Hot-spot temperature, overloads, 24-hour cycles, FAA, FEQA, loss of life and maximum load by loading type per IEEE C57.91, plus altitude, ambient and IEC 60076-7.
Open the calculatorPower quality calculator: THD, K-factor, unbalance and reactive power
Calculate harmonic distortion and K-factor, the real unbalance between the three voltages and the kvar needed to correct the power factor.
Open the calculatorCable size calculator: mm² and AWG, protection, short circuit and medium voltage
Cable size in mm² (IEC 60364-5-52) and AWG/kcmil (NEC) by current-carrying capacity, protection, short circuit, voltage drop, harmonics, neutral and PE, plus the current rating of medium-voltage cables per IEC 60287, with the IEEE 399 and IEEE 525 methods.
Open the calculatorPhysical unit converter: 111 quantities and nearly 1,200 units, from SI to traditional
Convert between every unit in use for 111 physical quantities: electrical, magnetic, thermal, mechanical, radiation and data, covering SI, imperial, US customary, CGS and traditional units.
Open the calculatorIEC 61620 calculator: tan δ and conductivity of insulating liquids
Calculate tan δ, conductivity, resistivity and permittivity of insulating oils from G and C to IEC 61620: square wave, test cell and repeatability.
Open the calculatorCoordinate converter: decimal degrees, DMS and UTM (WGS84, ETRS89 and ED50)
Convert coordinates between decimal degrees, DMS, UTM and Google Maps, Waze or Apple Maps links, with datum change between WGS84/ETRS89 and ED50. Free, in your browser.
Open the calculatorSecure password generator: 6 to 80 characters, with or without special characters
Generate random passwords of 6 to 80 characters, with all special characters, basic ones only or none. Exact entropy. Free, and nothing leaves your browser.
Open the calculatorWorld time zone map: the official time in every country right now
Interactive world time zone map with day and night: click a country or a zone to see its official time, its UTC offset, whether it is on daylight saving time and when the clocks change.
Open the calculatorBattery life forecast: state of health (SOH) and remaining life calculator
Enter the measurements of your lead-acid, nickel, lithium or sodium battery and get its state of health (SOH), estimated remaining life and a diagnosis to IEEE and IEC, with a PDF, DOCX or ODT report.
Open the calculatorHigh-voltage circuit-breaker diagnostics: timing, contact resistance, coils and SF6
Enter your HV circuit-breaker measurements and get the status per test and subsystem, the likely cause and an action plan to IEC 62271 or IEEE C37.
Open the calculatorPower transformer test calculator to IEC 60076-1
For power transformers: load loss and impedance at 75 °C, voltage drop, no-load, Table 1 tolerances, V/Hz overfluxing, tappings, zero-sequence impedance, vector group and cold measurement.
Open the calculatorElectric motor calculator to IEC 60034-1
For motors: winding temperature rise by the resistance method and its thermal-class limit, stopping-time correction, HVF, voltage unbalance, zones A and B, and Table 20 tolerances.
Open the calculatorIndicative result. The calculation runs in your browser and is not sent to any server. This website may contain errors or omissions: before making any decision about an installation, the information must be checked and validated by a qualified engineer. The battery and circuit breaker diagnostic tools run on Amperis servers; calculations are not stored unless you expressly choose to do so. Legal notice and terms of use