31 Engineering Calculators, Done Right

Fast, accurate, and free calculators for electrical, mechanical, and civil engineers. No signup required.

⚑ Electrical

🎯

Resistor Color Code

Decode 4-band and 5-band resistor color codes instantly. See resistance value, tolerance, and temperature coefficient.

Electrical πŸ”—

Series/Parallel Resistor

Calculate total resistance for resistors in series or parallel configurations. Add unlimited resistors.

Electrical ⚑

Voltage Divider

Calculate output voltage, current, and power dissipation for resistive voltage divider circuits.

Electrical πŸ”Œ

Cable Cross-Section

Size cables correctly based on current load, voltage drop, and installation method. Supports AWG and metric.

Electrical πŸ“‰

Voltage Drop

Calculate voltage drop and check NEC compliance for DC, single-phase, and three-phase circuits. Get recommended wire size.

Electrical βš™οΈ

Power Calculator

Calculate electrical power using Ohm's law. Find voltage, current, resistance, or power from any two values.

Electrical πŸ’‘

LED Resistor

Calculate the correct current-limiting resistor for any LED circuit. Get resistor value, E24 standard value, and power rating.

Electrical πŸ”‹

Capacitor Code

Decode ceramic capacitor markings (104, 473K) to pF, nF, and Β΅F. Or encode a value to get the EIA code.

Electrical πŸ“

Unit Conversion

Convert between engineering units: length, area, volume, pressure, temperature, and more.

General ⚑

Watts/Amps/Volts

Convert between watts, amps, and volts for DC, AC single-phase, and three-phase circuits. Includes power factor.

Electrical πŸ”Œ

Series Parallel Circuit

Calculate series and parallel equivalents for R, C, L, and mixed RLC circuits. Includes AC impedance, resonance, and Q factor.

Electrical

βš™οΈ Mechanical & Fluid

πŸ›’οΈ

Tank Volume

Calculate volume for cylindrical, rectangular, spherical, conical, and horizontal cylinder tanks. Supports partial fill.

Mechanical πŸ’§

Flow Rate

Calculate volumetric and mass flow rate for circular pipes and rectangular ducts. Output in L/min, GPM, mΒ³/h.

Mechanical βš™οΈ

RPM

Calculate RPM from frequency, gear/pulley ratios, or cutting speed (SFM). Supports metric and imperial units.

Mechanical

🌑️ HVAC & Energy

🌑️

Heating BTU

Calculate heating or cooling BTU requirements based on room size, insulation, climate zone, and windows.

HVAC β˜€οΈ

Solar Panel Angle

Calculate optimal solar panel tilt angle by latitude. Get year-round, seasonal, and monthly angles with city presets.

HVAC

πŸ—οΈ Construction & Materials

πŸ—οΈ

Metal Weight

Calculate weight of metal profiles: round bar, square bar, flat bar, hex bar, pipe, tube, plate, and angle. Supports MS, SS304, SS316, and GI.

Construction πŸ›£οΈ

Asphalt & Bitumen

Estimate asphalt tonnage for road paving or bitumen volume and barrel count. Supports metric and imperial units.

Construction 🧱

Concrete Block

Calculate the number of concrete blocks (CMU, cinder, half) needed for a wall, including waste allowance and mortar estimate.

Construction πŸͺ΅

Board Foot

Calculate board feet for lumber using nominal or actual dimensions. Supports single boards, multiple pieces, and cost estimation.

Construction πŸ–οΈ

Sand & Gravel

Calculate sand, gravel, and fill material quantities by volume or area. Get weight in tonnes, tons, and bag counts.

Construction 🏠

Rafter

Calculate common, hip, and valley rafter lengths from roof pitch or rise/run. Get birdsmouth cut dimensions and pitch angle.

Construction πŸ“

Plywood

Estimate plywood sheets for floors, walls, or roofs. Includes waste allowance, cost estimation, and recommended thickness.

Construction 🏘️

Siding

Calculate siding materials for vinyl, wood, fiber cement, or board & batten. Includes window/door deductions and cost.

Construction πŸ”§

Baluster Spacing

Calculate baluster count and exact spacing for deck railings and stairs. IRC 4-inch max gap compliance check included.

Construction πŸ“

Gradient & Slope

Convert between slope ratio, percentage, angle, and rise/run. Includes ADA compliance check for accessibility ramps.

Construction 🧣

Insulation

Calculate insulation R-value, depth, and material quantities for blow-in, batt/roll, and multi-layer projects.

Construction

πŸ’» Electronics

πŸ’»

Binary to Gray Code

Convert between binary and Gray code with step-by-step XOR visualization. Supports 4-bit, 8-bit, and custom bit widths.

Electronics πŸ“»

RC Filter

Calculate RC filter cutoff frequency, resistance, or capacitance. Supports low-pass/high-pass with E24 standard value recommendations.

Electronics

✈️ Aerospace

✈️

Crosswind

Calculate crosswind and headwind components from wind speed and angle. Includes crosswind limit check for safe operations.

Aerospace

πŸ”Š General

πŸ”Š

Decibel

Add, subtract, and convert decibels. dB addition, dB subtraction, dB↔linear, and dBm↔power calculations.

General

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Whether you're sizing a cable, decoding a resistor, or converting units on the job site, CoreCalx gets you the answer in seconds. Built by engineers, for engineers.

πŸ“– Latest Guides

New to these topics? Our engineering guides walk you through the theory behind each calculator: