Napkin Tools | Free Engineering Tools for Early Concept Decisions

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RD8 Napkin tools for mechanical engineers - Free to use

Often the most important decisions and estimates is made on the back of napkin. Napkin Tools is set of early stage tools and calculators intended for early concept stage calculations - so to speak - that can be made on the back of a napkin.

Multi Equation Solver

Laptop displaying a software interface showing a list of mechanical tolerances with status indicators and a 3D model of a mechanical component on the right.

Solve equation sets.

Simple, fast and with an interactive sketch canvas.

Go to the Multi Equation Solver

Clearance Calculator

Make quick and rough estimates for tolerance stacks.

See our contact and clearance calculator

Snap Fit Calculators

Quick estimates for design of snap fits.

Ensure your design is feasible before you model.

Go to Snap Fit Calculator

RD8 Product Specification Tool

Manage product specification and action points. Link your user needs to functional calculations (e.g. from RD8 Software).

See our Product Specification Tool

Spring Calculator

Dimension springs with minimum variation and desired safety factors. Test up to 2.5 million combos in seconds!

Go to the Spring Calculator

Guide Ratio Calculator

Interface showing parameters, technical schematic with force diagram, and system operational status at 60.5% efficiency.

Quick estimates for guide ratio and optimal slider design.

Ensure that energy is not lost to friction and that your design is operating with maximum efficiency.

See our Guide Ratio Calculator