Engineering toolkit
Mechanical Engineering Calculators
Practical calculation tools for mechanical design, tolerancing, sealing, fasteners and shaft connections. Start with the result, then inspect the engineering basis and assumptions inside each tool.
ISO 286 Fit Calculator
Calculate hole and shaft limits, clearance, interference and transition fits using the implemented ISO 286 tolerance data.
Engineering basis
ISO 286-1 / ISO 286-2
O-Ring Groove Calculator
Estimate groove geometry, squeeze, gland fill and installation conditions for common O-ring sealing arrangements.
Engineering basis
ISO 3601 series
GD&T Reference & Calculator
Explore geometric tolerances, datum use, tolerance-zone concepts and inspection guidance for ISO and ASME workflows.
Engineering basis
ISO 1101 / ASME Y14.5
Metric Thread & Bolt Calculator
Calculate metric thread geometry, stress area, preload, tightening torque estimates, clearance holes and engagement checks.
Engineering basis
ISO 724 / ISO 273 / ISO 898-1 / ISO 3506-1
Parallel Key Calculator
Select DIN parallel-key geometry and perform preliminary shear and bearing-pressure checks for keyed shaft connections.
Engineering basis
DIN 6885-1 / DIN 6892
Built for fast engineering work
DraftFit calculators are engineering aids. Standard-derived data, simplified estimates and assumptions are identified inside each tool. Safety-critical designs still require project-specific engineering verification and the applicable standards.