Free · Ad-free · No sign-up

Common Aerospace Calculations, done right.

Fluid properties, springs, seals, gears, stress allowables and electronics. Engineering calculators built by a working aerospace engineer, with every equation and source shown.

  • 170+ calculators & reference pages
  • 400+ fluids in Thermodynamics Land
  • MIL-HDBK-5 material allowables
  • NSWC-11 reliability models

Featured calculators

Tools worth a closer look

Some of the deepest calculators on the site. Each one turns an afternoon of hand calcs into a few seconds.

SpringsCompression spring terminology diagram showing free length, wire diameter and coil pitch

Compression Spring Calculator

Find rate, stress, buckling and fatigue life. Pick wire from a materials database. Export the 3D model as an STL.

Open calculator »
Fluid PropertiesChart of water enthalpy and entropy against temperature

Thermodynamics Land

Look up thermodynamic properties for 400+ fluids. Covers water, steam, refrigerants, gases and cryogens. Works in any unit system.

Open calculator »
Stress Analysis F_ty Temperature

Multi-Material Comparison

Compare up to ten MIL-HDBK-5 alloys. Plot strength and modulus against temperature. See room-temperature allowables side by side.

Open calculator »
FluidsCross-section of a sharp-edged thin-plate orifice

Orifice Flow Rate Calculator

Find flow rate from pressure drop, or solve for ΔP. Choose from eight orifice shapes.

Open calculator »
ReliabilityExamples of static and dynamic seals from the NSWC-11 handbook

NSWC-11 Seal Reliability

Estimate failure rates for O-rings, gaskets and seals. Every NSWC-11 factor is shown. Springs and washers are covered too.

Open calculator »
SpringsBelleville disc spring terminology diagram

Belleville Washer Calculator

Plot load against deflection for disc springs. Try different stacks. Check stress and fatigue, then preview the stack in 3D.

Open calculator »
Stress AnalysisLug nomenclature diagram showing edge distance, thickness and hole diameter

Lug & Pin Analysis

Size lugs and pins with the Bruhn method. Handles angled loads. Every failure mode gets a margin of safety.

Open calculator »
GearsThree ways to measure gear tooth thickness: chordal, span and over balls

Gear Tooth Thickness & Backlash

Set tooth thickness limits for a minimum backlash. Get chordal, span and over-balls sizes for the drawing.

Open calculator »
Stress AnalysisHertz contact cases: sphere, cylinder, crossed cylinders, cone and knife edge

Hertz Contact Stress

Find contact pressure, patch size and subsurface shear. Covers spheres, cylinders, a cone and a knife edge.

Open calculator »
ElectronicsMagnetic circuit of a solenoid with an air gap to the armature

Solenoid & Coil Designer

Design a solenoid coil for AC or DC. Get turns, resistance and pull force. See how hot it runs and how long it lasts.

Open calculator »
Stress AnalysisColumn buckling compared with local crippling failure modes

Column Buckling & Crippling

Check columns for buckling and local crippling. Works for tubes, angles, channels and more. Uses real MIL-HDBK-5 data.

Open calculator »
ProcessTank head shapes: flat, hemispherical, ellipsoidal, torispherical and conical

Tank & Vessel Volume

Find the volume of a partly filled tank. Works for any head shape. Generates a strapping table.

Open calculator »

KasperCalc for Business

Need a custom, enterprise-grade calculator?

We build secure engineering tools for your products and your test floor. That includes design calculators, calibration algorithms and test-bench data checks. Turn a spreadsheet full of readings into a clear pass or fail.

Get a custom quote » See what we build
  • Private calculators built around your parts and specs
  • Automated MCU programming & calibration stations
  • Pass/fail validation for test-bench data
  • Data acquisition, mechanical & PCB design

Browse everything

All calculators

Every tool on KasperCalc, grouped by discipline.