Tolerance Master

An ISO 286 limits-and-fits workspace with tabulated deviations, target-clearance solving, tolerance-zone diagrams, preferred fits, dual units, and history.

Tolerance Master is a limits-and-fits workspace for mechanical design, machining, inspection, and education. Based on the ISO 286 and GB/T 1800 tolerance systems, it connects direct lookup, inverse fit selection, visual checking, and saved results in one focused workflow.

LIMITS & FITS • Basic sizes greater than 0 and up to 3150 mm • Common hole zones A–ZC and shaft zones a–zc • Valid tolerance grades filtered dynamically by size and tabulated availability • Upper and lower deviations plus maximum and minimum limit sizes • Minimum and maximum clearance with clearance, transition, or interference classification • Switch results between micrometres and millimetres

SOLVE FROM THE TARGET • Enter the clearance or interference range you need • Rank standard H-basis combinations deterministically • Compare candidates and return one to the main calculator for verification • Start quickly from preferred fit combinations

VISUAL AND TRACEABLE • See the zero line, hole and shaft tolerance zones, and clearance range together • Save up to 100 calculations locally and restore them in one tap • Share a structured text summary of inputs, deviations, limits, and fit type • Move between Calculator, Fit Guide, and History workspaces

Standards data and calculations run on device. Engineering inputs and saved history are not uploaded. This app is an engineering aid and does not reproduce the standards. Before critical design or production release, verify the applicable standard edition, drawing requirements, material, process, and inspection method.

This app includes a 3-day local trial. Continued Pro access requires a separate monthly subscription purchase. A purchased subscription renews automatically unless cancelled in your Apple account settings.

Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/