What is engineering in simple terms?

Engineering is the application of math, science, and practical judgment to design, build, and maintain systems, structures, machines, and processes that solve real-world problems. Engineers turn ideas into reliable, safe, and efficient solutions.

Which branches of engineering are covered by these calculators?

CalcDomain’s engineering hub covers civil and structural engineering (beams, columns, foundations, loads), mechanical engineering (fluids, heat transfer, HVAC, machinery), electrical and power systems (Ohm’s law, ampacity, voltage drop, three-phase power), chemical and process engineering (reactors, distillation, membranes), and general engineering tools such as Reynolds number, Bernoulli, and Manning’s equation.

Are these engineering calculators suitable for professional use?

The calculators are designed around standard formulas and common design codes (such as ACI, AISC, ASCE, Eurocodes, NEC, and BS 7671 where noted). They are excellent for preliminary design, checks, teaching, and quick what-if studies. Final designs should always be reviewed by a qualified engineer and checked against the latest code provisions and project-specific requirements.

How do I choose the right engineering calculator for my problem?

Start from your discipline: civil/structural, mechanical, electrical, or process. Then identify the physical quantity or component you are dealing with – for example, beam deflection, pipe flow, voltage drop, or reactor sizing. Each calculator page includes a description, required inputs, formulas, and example problems to help you confirm you are using the right tool.

Can I use these tools for learning and exam preparation?

Yes. Every engineering calculator on CalcDomain is paired with step-by-step formulas, worked examples, and conceptual explanations. This makes them ideal for students who want to see how theory connects to real numbers and for professionals refreshing specific topics.

Engineering Calculators & Technical Tools

This is CalcDomain’s central hub for engineering: a curated collection of civil, structural, mechanical, electrical, and process engineering calculators with clear formulas, units, and worked examples.

Use these tools for quick design checks, homework, feasibility studies, and day‑to‑day engineering decisions. Every calculator page explains the equations behind the numbers so you can trust and verify your results.

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Featured engineering calculator groups

Civil & Structural Engineering

Design and check beams, columns, foundations, retaining walls, and geotechnical capacity using standard codes and classical mechanics.

Browse all structural tools

Mechanical & HVAC Engineering

Analyze fluid flow, heat transfer, HVAC loads, machinery, and rotating equipment with practical, unit‑aware calculators.

Browse all mechanical tools

Electrical & Power Systems

From Ohm’s law to NEC ampacity, three‑phase power, and filter design, these tools support low‑voltage, power, and electronics work.

Browse all electrical tools

Chemical & Process Engineering

Size reactors, columns, and separation units, and analyze flows and energy balances in process plants.

See more process tools

General & Cross‑Discipline Tools

Core formulas and models that appear across many branches of engineering, from fluid mechanics to reliability and operations.

View all engineering categories

What is engineering?

Engineering is the disciplined application of mathematics, science, and practical experience to design, build, and maintain systems that solve real‑world problems. Unlike pure science, which focuses on understanding how the world works, engineering focuses on creating things that work reliably, safely, and efficiently.

Major branches include:

Civil & structural engineering – buildings, bridges, roads, foundations, water and wastewater systems.
Mechanical engineering – machines, vehicles, HVAC, manufacturing, thermodynamics, and fluid mechanics.
Electrical and electronics engineering – power generation and distribution, electronics, control systems, communications.
Chemical & process engineering – chemical plants, reactors, separation processes, energy and mass transfer.
Systems, software, and industrial engineering – complex systems, optimization, reliability, operations, and automation.

Core engineering relationships and formulas

Many engineering calculators on this site are built around a small set of fundamental physical relationships. Understanding these helps you interpret any result.

1. Conservation of mass

For a steady‑state system with one inlet and one outlet:
\[ \dot{m}_{\text{in}} = \dot{m}_{\text{out}} \]
where \(\dot{m}\) is mass flow rate (e.g. kg/s).

In more complex systems, the general form is:

\[ \frac{d m_{\text{system}}}{dt} = \sum \dot{m}_{\text{in}} - \sum \dot{m}_{\text{out}} \]

2. Newton’s second law (mechanics)

\[ \sum \vec{F} = m \vec{a} \] where \(\sum \vec{F}\) is the sum of forces, \(m\) is mass, and \(\vec{a}\) is acceleration.

This underpins structural analysis (internal forces and moments), vibration, and dynamics calculators.

3. Stress and strain

Normal stress: \[ \sigma = \frac{F}{A} \] Strain: \[ \varepsilon = \frac{\Delta L}{L_0} \] Hooke’s law (linear elastic region): \[ \sigma = E \varepsilon \]

Here \(F\) is axial force, \(A\) is cross‑sectional area, \(\Delta L\) is change in length, \(L_0\) is original length, and \(E\) is Young’s modulus.

4. Energy and power

Mechanical work: \[ W = F \cdot s \] Power: \[ P = \frac{dW}{dt} \] Electrical power (DC): \[ P = V I \]

Many calculators convert between mechanical, electrical, and thermal power units (W, hp, BTU/hr, etc.).

5. Fluid flow and Reynolds number

Reynolds number: \[ \mathrm{Re} = \frac{\rho V D}{\mu} \] where \(\rho\) is density, \(V\) is mean velocity, \(D\) is characteristic length (e.g. pipe diameter), and \(\mu\) is dynamic viscosity.

\(\mathrm{Re}\) determines whether flow is laminar or turbulent and influences friction factors and pressure drop.

6. Ohm’s law and impedance

Ohm’s law: \[ V = I R \] For AC circuits, impedance \(Z\) generalizes resistance: \[ V = I Z \]

Electrical calculators extend this to three‑phase systems, power factor, and frequency‑dependent reactance.

How to use engineering calculators effectively

Define the problem clearly. Identify what you need to solve for (e.g. required beam size, pressure drop, motor power).
Gather realistic input data. Use appropriate units, material properties, and safety factors from standards or datasheets.
Check units and ranges. If a result looks unreasonable, verify units and input magnitudes first.
Use calculators as decision support, not as the only authority. Final designs should be checked against the latest codes and reviewed by a qualified engineer.

FAQ about engineering & these tools

Is engineering more about math or creativity?

Both. Math and physics provide the constraints and quantitative checks; creativity and judgment are needed to choose concepts, simplify problems, and balance trade‑offs such as cost, safety, and performance.

Can these calculators replace professional engineering software?

No. They are ideal for quick checks, education, and early‑stage design, but they do not replace full finite‑element models, detailed code checks, or multi‑discipline coordination. Think of them as fast, transparent tools that complement heavier software.

Where do the formulas come from?

The formulas are drawn from standard engineering textbooks, widely used design codes (ACI, AISC, ASCE, Eurocodes, NEC, BS 7671, etc.), and peer‑reviewed references. Each individual calculator page cites the specific assumptions and equations it uses.