Engineering Calculators

EngiBench groups calculators across fluid and pumps, boiler and steam, fluid flow, HVAC, and electrical engineering. The directory includes pump, pipe-flow, pressure-drop, Reynolds-number, BTU, CFM, boiler, steam-property, electrical-power, three-phase, power-factor, and voltage-drop tools. Use the search box or category filters to narrow the list quickly.

Start with the pump quantity you need. Use Pump Head for head, Pump Power for hydraulic or shaft power, Pump Flow for flow rate, Pump Efficiency for efficiency, NPSH for suction conditions, or Boiler Feed Pump for feedwater-system requirements. Searching “pump” at the top shows the relevant tools together.

Use the Pressure Drop Calculator for friction and system pressure-loss work. If you need the Darcy-Weisbach relationship specifically, use the Darcy-Weisbach Calculator. Pipe Flow, Flow Velocity, Reynolds Number, and Hydraulic Diameter can provide supporting quantities used in a more complete fluid-system analysis.

Use the Electrical Power Calculator for general voltage, current, resistance, and AC power relationships. For a balanced three-phase system, the Three Phase Power Calculator is more specific. Power Factor Calculator handles real, reactive, and apparent power relationships, while Ohm's Law covers the core V, I, R, and P relationships.

Use the Three Phase Power Calculator. It is designed for balanced three-phase real, apparent, and reactive power as well as current and voltage calculations. It also distinguishes line-to-line from line-to-neutral voltage. For related AC power-factor work, use the Power Factor Calculator from the same Electrical category.

Use the Voltage Drop Calculator for DC, single-phase AC, and balanced three-phase AC conductor voltage drop. It reports voltage drop, percentage, and load voltage and also includes maximum-length and minimum-conductor-size tools. Voltage-drop sizing remains separate from ampacity and electrical-code checks.

Use the CFM Calculator for airflow in cubic feet per minute, the Duct Size Calculator for duct dimensions, and the Air Changes Per Hour Calculator when room volume and ventilation rate are the focus. The HVAC category also includes heating-load, cooling-load, and BTU tools for thermal requirements.

Use the BTU Calculator for heating or cooling requirements expressed in British thermal units. If your goal is a more building-oriented thermal estimate, the Heating Load and Cooling Load calculators provide separate workflows. All three are grouped under HVAC so they can be compared without leaving the directory.

Use the Reynolds Number Calculator. It supports velocity, flow-rate, kinematic-viscosity, and hydraulic-diameter methods and identifies the flow context. The Fluid Flow category also contains Pipe Flow, Flow Velocity, Pressure Drop, Darcy-Weisbach, and Hydraulic Diameter tools for related calculations and supporting engineering checks.

Yes. The calculators are intended to make common engineering calculations easier to perform, review, and understand. They are appropriate for preliminary work, learning, cross-checks, and early design studies. Final design, equipment selection, safety-critical decisions, code compliance, and contractual calculations should still use applicable standards, manufacturer data, verified software, and qualified engineering review.

The directory is designed as a collection of free online engineering tools. Each card links directly to its calculator page without requiring a calculation on the directory itself. Availability or site policies can change over time, so the individual calculator page remains the authoritative place for the current tool and its engineering limitations.

Yes. The directory is responsive, with a one-column mobile card layout, horizontally scrollable filters, a mobile navigation menu, and touch-friendly links. Individual calculator pages may contain more complex inputs, but the directory is optimized so users can find and open the right tool quickly on smaller screens.

The individual calculator pages are designed to show the engineering formulas, inputs, units, results, and calculation breakdowns relevant to that tool. This directory deliberately avoids repeating those technical details. Its job is to help you find the right calculator, then take you directly to the page where the calculation method is explained.

Many EngiBench calculator pages support multiple engineering units appropriate to the calculation, such as SI and US customary units, electrical power units, pressure units, airflow units, or pipe dimensions. Unit options are handled on each calculator page rather than on this directory because the relevant units differ by engineering discipline.

No single online calculator should automatically be treated as final design approval. Use EngiBench results as engineering estimates, cross-checks, and study tools. Final work may require standards, code requirements, certified property data, equipment curves, safety factors, installation constraints, calibrated measurements, and professional review that go beyond a calculator's defined scope.