ISO 286 Fits & Tolerances Calculator

• •Use the ISO 286 Fits & Tolerances Calculator when solving homework or exam problems that require quick numerical verification of your hand calculations — instant feedback helps identify arithmetic errors before they propagate.
• •Use it during the early design phase to rapidly iterate on parameters and narrow down feasible configurations before committing time to detailed finite element simulations or full design packages.
• •Use it when reviewing a colleague's calculation or checking a vendor's data sheet for plausibility — a quick sanity check can prevent costly downstream errors.
• •Use it to generate reference data for a technical report or presentation without manual computation, ensuring consistent, reproducible numbers throughout the document.
• •Use it in the field when a quick estimate is needed and a full engineering software package is not available.

The ISO 286 Fits & Tolerances Calculator is a precision engineering calculation tool designed for students, engineers, and technical professionals. Shaft-hole fit calculator using ISO 286 IT grades. Enter H7/f6, H7/k6, H7/p6 etc. to get hole/shaft limits, clearance/interference, and fit type. All calculations are performed using established engineering formulas from the relevant scientific literature and standards. Inputs support both metric (SI) and imperial unit systems, with unit conversion handled automatically — simply select your preferred unit from the dropdown next to each field. Results are computed instantly in the browser without sending data to a server, ensuring both speed and privacy. This calculator is intended as a supplementary tool for learning and design exploration; always verify results against authoritative references for safety-critical applications.

ANSI B4.1 and ISO 286 define standardized fits and tolerances for mating parts (shaft and hole). A 'fit' is the relationship between the two dimensions — clearance fit (always a gap), transition fit (can be gap or interference depending on actual dimensions within tolerance), or interference fit (always overlapping, requiring force to assemble). ISO fits are specified by a letter (hole tolerance position) and number (tolerance grade). H7/g6 is a common sliding fit — H7 hole with g6 shaft gives a small clearance. H7/p6 is a common interference fit. Tolerance grades IT1-IT16 define the tolerance magnitude: IT6 is typical for precision gauge work, IT7 for machine parts, IT8 for general machining, IT11+ for cast and forged parts. The basic size is the nominal dimension; tolerances are specified as deviations from basic size. For a shaft, lower deviation is (−) and upper deviation is 0 or (+), depending on fit. For a hole, lower deviation is 0 or (+) and upper is (+). Clearance fits include H11/c11 (loose), H9/d9 (free running), H8/f7 (close running), H7/g6 (sliding), H7/h6 (locational slide). Interference fits include H7/n6 (locational transition), H7/p6 (press), H7/s6 (medium drive), H7/u6 (force). Selection depends on function: precision assembly (h6 or h5 shafts), loose running machinery (c11), press fits without keys (p6 or tighter), etc.

• •Machine design: select appropriate fits for bearings, shafts, bushings, pins, and press-fit assemblies based on function and precision requirements.
• •Bearing installation: interference fits between bearings and shafts require specific tolerance ranges to avoid damage during installation and ensure adequate retention.
• •Gear and pulley mounting: press-fit or keyed mounting of gears on shafts requires correct shaft tolerance for reliable assembly.
• •Precision instrument manufacture: very tight tolerances (IT5, IT6) are needed for optical instruments, metrology equipment, and high-precision mechanisms.
• •Automotive and aerospace manufacturing: standardized fits ensure interchangeability of parts across different production lots and suppliers.