Engineering Calculator
An engineering calculator is a scientific calculator tuned for the specific equations engineers use every day: stress and strain in mechanical engineering, safety factor in civil engineering, Ohm's law in electrical engineering, beam deflection in structural work, and pressure-to-force in piping and pneumatics. This online engineering calculator combines all of them in one form, so you pick a mode and enter the two or four inputs it asks for. Output comes back in both US and SI units.
What this engineering calculator does
Six of the most-used engineering equations in one place:
- Stress (sigma = F / A) in psi, plus the MPa equivalent. Core mechanical engineering equation.
- Strain (epsilon = delta L / L), unitless, plus microstrain.
- Safety factor (N = sigma_yield / sigma_applied), plus margin of safety. Primary civil engineering calculator output for structural sizing.
- Electrical power (P = I x V) in watts and kW. Standard electrical engineering calculator output.
- Beam deflection (delta = F L^3 / (48 E I)) for a simply supported beam under a center point load. Result in inches and mm.
- Force from pressure (F = P x A) in lbf and newtons.
Mechanical engineering calculator examples
A 10,000 lbf tensile load on a 1 in^2 bar gives sigma = 10,000 psi = 68.9 MPa. That is well under the 36,000 psi yield of A36 steel (safety factor = 3.6). A strain of 0.002 over a 10 inch gauge length is 200 microstrain, typical for a bar in elastic tension.
Civil engineering calculator examples
For allowable stress design of an A36 steel member with 36,000 psi yield and a 24,000 psi applied stress, N = 36,000 / 24,000 = 1.5. That margin of safety (0.5, or 50 percent) is the minimum for most steel building codes. The civil engineering calculator returns both numbers.
Electrical engineering calculator examples
A 12 A load on a 120 V circuit draws P = 12 x 120 = 1,440 W = 1.44 kW. At $0.12/kWh for 8 hours a day, that is about $1.38/day. This is the same P = IV equation every scientific calculator for engineering does, bundled with the other common equations here.
Best engineering calculator formats
Physical engineering calculators (Casio fx-991EX, HP Prime, TI-36X Pro) are the best graphing calculator for engineering students during exams, but a best engineering calculator for daily field work is whatever is on your phone or laptop. A Casio calculator for engineering handles the same equations this online engineering calculator handles, but with manual input of formulas. The mechanical engineering calculator modes here save you the trouble of retyping F = P x A or sigma = F / A every time. That is the whole point of an engineering calculator app: speed on the equations you actually use.
Engineering calculator software vs online tools
Dedicated engineering calculator software (MathCAD, PTC Creo Calcs, SMath, Engineering Equation Solver) gives you unit tracking and full FEA integration, valuable for production work. An online engineering calculator like this one covers the 80 percent case fast: quick sanity checks, back-of-envelope sizing, student homework. Pick the tool to match the job.
Beam deflection example
A 1000 lbf load at the center of a 60 inch long, 1 inch diameter steel bar (E = 29e6 psi, I = pi x 1^4 / 64 = 0.0491 in^4) gives delta = (1000 x 60^3) / (48 x 29e6 x 0.0491) = 3.16 inches. That is way past the allowable, so in practice you would need a much larger section.