A tool for converting between km, m, cm, mm, ft, in, mil, yd, mi, and nmi, commonly used in construction, engineering, navigation, and daily life. This calculator converts length units between metric and imperial systems. Input any one value, and all others are automatically calculated. Ideal for international projects, cross-disciplinary work, and education. Supported Units & Relationships Unit Full Name Description Conversion km Kilometer 1 km = 1000 m, used for long distances 1 km = 1000 m m Meter SI base unit of length 1 m = 100 cm = 1000 mm cm Centimeter 1 cm = 0.01 m, used for small measurements 1 cm = 10 mm < mm Millimeter 1 mm = 0.001 m, used in precision machining 1 mm = 0.03937 in ft Foot 1 ft = 12 in, used in construction 1 ft = 0.3048 m in Inch 1 in = 25.4 mm, used for screen sizes 1 in = 2.54 cm mil Thousandth of an inch 1 mil = 0.001 in, used for wire thickness 1 mil = 0.0254 mm yd Yard 1 yd = 3 ft, used in sports fields 1 yd = 0.9144 m mi Statute mile 1 mi = 5280 ft, used for road distances 1 mi = 1.60934 km nmi Nautical mile 1 nmi = 1852 m, used in maritime navigation 1 nmi = 1.852 km Key Conversion Formulas 1 km = 1000 m 1 m = 100 cm = 1000 mm 1 ft = 0.3048 m 1 in = 2.54 cm = 25.4 mm 1 yd = 3 ft = 0.9144 m 1 mi = 1.60934 km 1 nmi = 1852 m = 1.852 km 1 mil = 0.001 in = 0.0254 mm Example Calculations Example 1: 1 meter = ? inches → 100 cm ÷ 2.54 ≈ 39.37 inches Example 2: 1 mile = ? kilometers → 1.60934 km Example 3: 1 nautical mile = ? meters → 1852 meters Example 4: 1 inch = ? millimeters → 25.4 mm Example 5: 1 yard = ? feet → 3 feet Example 6: 1000 mm = ? inches → 1000 × 0.03937 ≈ 39.37 inches Example 7: 1 mil = ? millimeters → 0.0254 mm Use Cases Construction and civil engineering Mechanical manufacturing and parts machining Maritime and aviation navigation International trade and logistics Teaching and student learning Daily life measurements (e.g., home renovation, shopping)

A tool for converting between Celsius (°C), Fahrenheit (°F), and Kelvin (K), commonly used in meteorology, engineering, science, and daily life. This calculator converts temperature values between the three most common scales. Input any one value, and the other two are automatically calculated. Ideal for international data, scientific research, and cross-cultural communication. Supported Units & Relationships Unit Full Name Description Conversion Formula °C Degree Celsius The most widely used temperature scale, with water freezing at 0°C and boiling at 100°C. - °F Degree Fahrenheit Used primarily in the United States, with water freezing at 32°F and boiling at 212°F. °F = (9/5) × °C + 32 K Kelvin Absolute temperature scale, where 0 K is absolute zero (-273.15°C), used in physics and chemistry. K = °C + 273.15 Key Conversion Formulas °F = (9/5) × °C + 32 °C = (°F - 32) × 5/9 K = °C + 273.15 °C = K - 273.15 °F = (9/5) × (K - 273.15) + 32 Example Calculations Example 1: 37°C → °F = (9/5)×37 + 32 = 98.6°F, K = 37 + 273.15 = 310.15 K Example 2: 98.6°F → °C = (98.6 - 32) × 5/9 = 37°C, K = 37 + 273.15 = 310.15 K Example 3: 273.15 K → °C = 273.15 - 273.15 = 0°C, °F = (9/5)×0 + 32 = 32°F Example 4: -40°C = -40°F (the only temperature where both scales read the same) Use Cases Meteorological data interpretation and international comparison Engineering design and material testing Chemical reaction temperature control Physics experiments and academic research Travel and cross-cultural communication (e.g., reading weather in the US) Teaching and student learning

A tool for converting between bit, Byte, kB, MB, GB, and TB, commonly used in computer science, networking, and storage capacity evaluation. This calculator converts digital information units. Input any one value, and all others are automatically calculated. Ideal for file size estimation, network speed, and storage device capacity. Supported Units & Relationships Unit Full Name Description Conversion b Bit The smallest unit of information, representing a binary digit (0 or 1) 1 Byte = 8 bits B Byte Basic data unit in computing, typically composed of 8 bits 1 B = 8 b kB Kilobyte 1 kB = 1024 Bytes 1 kB = 1024 B MB Megabyte 1 MB = 1024 kB 1 MB = 1,048,576 B GB Gigabyte 1 GB = 1024 MB 1 GB = 1,073,741,824 B TB Terabyte 1 TB = 1024 GB 1 TB = 1,099,511,627,776 B Key Conversion Formulas 1 Byte = 8 bits 1 kB = 1024 B 1 MB = 1024 kB = 1024² B 1 GB = 1024 MB = 1024³ B 1 TB = 1024 GB = 1024⁴ B Example Calculations Example 1: 1 GB = ? Bytes 1 GB = 1024 × 1024 × 1024 = 1,073,741,824 B Example 2: 100 MB = ? kB 100 × 1024 = 102,400 kB Example 3: 8,388,608 B = ? MB 8,388,608 ÷ 1,048,576 = 8 MB Example 4: 1 TB = ? GB 1 TB = 1024 GB Example 5: 100 Mbps = ? MB/s 100,000,000 bits/s ÷ 8 = 12.5 MB/s Use Cases File size estimation and compression Network bandwidth calculation (e.g., download speed) Storage device capacity comparison (e.g., SSD, USB) Memory analysis in programming and algorithms Data center and cloud computing resource planning Teaching and student learning

A tool for converting between AWG, mm², kcmil, mm, and inches, commonly used in electrical engineering and wiring design. This calculator converts wire sizes between different units. Input any one value, and all others are automatically calculated. Ideal for cable selection, electrical installations, and power system design. Supported Units & Relationships Unit Full Name Description AWG American Wire Gauge A logarithmic standardized system; higher numbers indicate thinner wires. Widely used in North America. mm² Square millimeters International unit for cross-sectional area of wire. kcmil / MCM Kilo-circular mil 1 kcmil = 1000 circular mils; used for large cables like transformer leads. mm Millimeter Diameter in millimeters, useful for measurement. in Inch Diameter in inches, primarily used in North America. Key Conversion Formulas AWG → mm²: d_mm = 0.127 × 92^((36 - AWG)/39) A = π/4 × d_mm² kcmil → mm²: mm² = kcmil × 0.5067 mm → in: in = mm / 25.4 Example Calculations Example 1: AWG 12 → mm² Diameter ≈ 2.053 mm → Area ≈ 3.31 mm² Example 2: 6 mm² → AWG ≈ 10 Example 3: 500 kcmil → mm² ≈ 253.35 mm² Example 4: 5 mm = 0.1969 in Example 5: AWG 4 → kcmil ≈ 417.4 kcmil Use Cases Wire and cable selection and procurement Electrical installation and wiring design Power system capacity calculation Industrial equipment wiring standards Electrical exams and teaching DIY electronics and PCB design

A tool for converting between phase angle φ (degrees/radians) and its sine, cosine, and tangent values, commonly used in electrical engineering and power systems. This calculator computes the trigonometric functions of the phase shift angle φ between voltage and current in AC circuits. Input any one parameter (φ, sin φ, cos φ, or tan φ), and all others are automatically calculated. Supported Parameters & Relationships Parameter Meaning Mathematical Relation φ (°) Phase angle in degrees Angle between voltage and current, in degrees φ (Rad) Phase angle in radians φ_rad = φ_deg × π / 180 Sin φ Sine of φ sin(φ) Cos φ Cosine of φ (Power Factor) cos(φ), i.e., Power Factor PF = P/S Tan φ Tangent of φ tan(φ) = sin(φ)/cos(φ) Example Calculations Example 1: Given φ = 30° Then: - φ (Rad) ≈ 0.5236 rad - sin φ ≈ 0.5 - cos φ ≈ 0.866 (Power Factor) - tan φ ≈ 0.577 Example 2: Given cos φ = 0.8 Then: - φ ≈ 36.87° - φ (Rad) ≈ 0.6435 rad - sin φ ≈ 0.6 - tan φ ≈ 0.75 Example 3: Given tan φ = 1.732 Then: - φ ≈ 60° - cos φ ≈ 0.5 (Power Factor) - sin φ ≈ 0.866 Use Cases Power system design and analysis Motor and transformer performance evaluation Power quality monitoring (power factor correction) Industrial energy efficiency optimization Electrical engineering exams and teaching Electronic circuit simulation and debugging

A tool for converting between common angle units such as degrees-minutes-seconds, decimal degrees, radians, and grads. This calculator allows you to convert angles between different units used in geography, navigation, mathematics, and engineering. Input one value, and all others are automatically calculated. Supported Units & Conversion Factors Unit Full Name Relation to Degree (°) Sexagesimal degree Degrees-Minutes-Seconds 1° = 60′, 1′ = 60″ Example: `90° 20′ 30″ = 90 + 20/60 + 30/3600 ≈ 90.3417°` Sexagesimal degree (decimal) Decimal Degrees 1° = 1° (direct representation) Radian Radian 1 rad = 180° / π ≈ 57.2958° 1° = π / 180 ≈ 0.017453 rad Centesimal degree Grad (or Gon) 1 grad = 0.9° 1° = 100 centesimal minutes 1 grad = 100 centesimal seconds Example Calculations Example 1: Input: `90° 20′ 30″` Convert to decimal degrees: `90 + 20/60 + 30/3600 = 90.3417°` Example 2: Input: `90.3417°` Convert to radians: `rad = 90.3417 × π / 180 ≈ 1.5768 rad` Example 3: Input: `π/2 rad ≈ 1.5708 rad` Convert to grads: First to degrees: `1.5708 × 180 / π ≈ 90°` Then to grads: `90° × 100 / 90 = 100 grad` So: `π/2 rad = 100 grad` Example 4: Input: `123.4 grad` Convert to degrees: `123.4 × 0.9 = 111.06°` Then to DMS: - 111° - 0.06 × 60 = 3.6′ → 3′ 36″ So: `123.4 grad ≈ 111° 3′ 36″` Use Cases Geographic Information Systems (GIS) and map coordinates Navigation and aviation positioning Mathematics education and trigonometric calculations Robotics motion control Astronomy and timekeeping Engineering drawing and mechanical design

A tool for converting between common pressure units such as bar, Pa, kPa, MPa, atm, psi, mmHg, inHg, mmH₂O, inH₂O, N/cm², and kg/cm². This calculator allows you to convert pressure values between different units used in engineering, meteorology, medical devices, and industrial applications. Input one value, and all others are automatically calculated. Supported Units & Conversion Factors Unit Full Name Relation to Pascal (Pa) bar Bar 1 bar = 100,000 Pa Pa Pascal 1 Pa = 1 N/m² hPa Hectopascal 1 hPa = 100 Pa kPa Kilopascal 1 kPa = 1,000 Pa MPa Megapascal 1 MPa = 1,000,000 Pa atm Atmosphere 1 atm ≈ 101,325 Pa N/cm² Newton per square centimeter 1 N/cm² = 10,000 Pa kg/cm² Kilogram per square centimeter 1 kg/cm² ≈ 98,066.5 Pa psi Pound per square inch 1 psi ≈ 6,894.76 Pa psf Pound per square foot 1 psf ≈ 47.8803 Pa mmH₂O Millimeter of water 1 mmH₂O ≈ 9.80665 Pa inH₂O Inch of water 1 inH₂O ≈ 249.089 Pa mmHg Millimeter of mercury 1 mmHg ≈ 133.322 Pa inHg Inch of mercury 1 inHg ≈ 3,386.39 Pa Example Calculations Example 1: Car tire pressure is 30 psi Then: - kPa = 30 × 6.895 ≈ 206.85 kPa - bar = 206.85 / 100 ≈ 2.07 bar - atm = 206.85 / 101.325 ≈ 2.04 atm Example 2: Blood pressure is 120 mmHg Then: - Pa = 120 × 133.322 ≈ 15,998.6 Pa - kPa = 15.9986 kPa - psi = 15.9986 / 6.895 ≈ 2.32 psi Example 3: HVAC duct static pressure is 200 Pa Then: - mmH₂O = 200 / 9.80665 ≈ 20.4 mmH₂O - inH₂O = 20.4 / 25.4 ≈ 0.80 inH₂O - hPa = 200 / 100 = 2 hPa Use Cases Hydraulic and pneumatic system design Tire pressure regulation Medical devices (blood pressure monitors, ventilators) Meteorology and weather forecasting Vacuum technology and sensor calibration Academic learning and exams

This calculator estimates the theoretical runtime of a battery under a given load. By entering battery configuration and load parameters, you can determine the expected duration of power supply. Parameter Description Connection -Select the battery connection type: --Series: Voltages add up, capacity remains unchanged --Parallel: Voltage remains constant, capacities add up Number of Batteries -Total number of batteries in the system. The total voltage and capacity are calculated based on the connection type. Voltage (V) -Nominal voltage of a single battery, in volts (V). Capacity (Ah) -Rated capacity of a single battery, in ampere-hours (Ah). Load (W or A) -Power consumption of the connected device. Two input options: --Power (W): In watts, suitable for most appliances --Current (A): In amperes, when operating current is known Peukert Constant (k) -A coefficient used to correct for capacity loss at higher discharge rates. Typical values by battery type: --Lead-Acid: 1.1 – 1.3 --Gel: 1.1 – 1.25 --Flooded: 1.2 – 1.5 --Lithium-Ion: 1.0 – 1.28 -An ideal battery has a Peukert constant of 1.0. Real batteries have values greater than 1.0, which typically increase with age. Depth of Discharge (DoD) -The percentage of battery capacity that has been discharged relative to full capacity.DoD = 100% - SoC (State of Charge). -Can be expressed in percent (%) or ampere-hours (Ah). In some cases, actual capacity exceeds rated capacity, so DoD may exceed 100%.

This tool calculates key parameters of transformer primary and secondary windings, such as voltage, number of turns, wire size, and resistance. Enter known values, select the parameter to calculate, and get instant results. Ideal for power supply design, repair, and learning.

Calculate the heat energy dissipated in resistive elements of a circuit. "Power dissipated in the form of heat in the resistive elements of the circuit." Key Formula: Joule's Law Q = I² × R × t or Q = P × t Where: Q : Heat energy (joules, J) I : Current (amperes, A) R : Resistance (ohms, Ω) t : Time (seconds, s) P : Power (watts, W) Note : Both formulas are equivalent. Use $ Q = I^2 R t $ when you know current and resistance. Parameter Definitions 1. Resistance (R) The tendency of a material to oppose the flow of electric current, measured in ohms (Ω). Higher resistance leads to more heat generation for the same current. Example : A 100 Ω resistor limits current and produces heat. 2. Power (P) Electrical power supplied or absorbed by a component, measured in watts (W). 1 watt = 1 joule per second. You can calculate it as: P = I² × R or P = V × I Example : A 5W LED uses 5 joules every second. 3. Current (I) The flow of electric charge through a material, measured in amperes (A). Heat is proportional to the square of the current — doubling current quadruples heat! Example : 1 A, 2 A, 10 A — each produces vastly different heat levels. 4. Time (t) Duration for which current flows, measured in seconds (s). Longer time → more total heat generated. Example : 1 second vs. 60 seconds → 60x more heat. How It Works When current flows through a resistor: Electrons move through the material They collide with atoms, losing kinetic energy This energy is transferred as vibrational energy → heat Total heat depends on: current, resistance, and duration The process is irreversible — electrical energy is lost as heat. Application Scenarios Designing heating elements (e.g., electric stoves, hair dryers) Calculating power loss in transmission lines Estimating temperature rise in PCB traces and components Selecting appropriate resistors based on power rating Understanding why devices get hot during operation Safety analysis in circuits (preventing overheating and fire risk)