Tolerance Fit Calculator

Tolerance Fit Calculator + Smart Fit Recommendation + 3D Visualization + 7 Practical Tools – one-tap calculation of hole and shaft tolerances。

"Tolerance Fit Calculator" is a professional tool app designed for mechanical engineers, machining technicians, and mechanical engineering students. Based on the ISO 286 standard, simply enter the nominal diameter and calculate limit deviations, fit type, maximum clearance/interference with one tap. Provides smart fit recommendations, 3D visualization, thread calculations, material weight calculation, and other practical features. Fully offline, no internet required, carry it with you anytime, anywhere.

Core Features

Tolerance Fit Calculation

Supports nominal diameters from 0 to 3150 mm, all tolerance zones for holes A～ZC, all tolerance zones for shafts a～zc, all tolerance grades IT1～IT18

Automatically identifies clearance fit, transition fit, and interference fit

Smart fit recommendation engine: automatically recommends the optimal tolerance combination based on fit requirements

3D Visualization

2D tolerance zone diagram: intuitively shows the relative positions of hole and shaft deviation ranges

3D model assembly: dynamically demonstrates the looseness/tightness under maximum clearance/maximum interference conditions, supports gesture rotation and zoom

Practical Tool Set (7 Tools)

Thread & fastener calculation: thread tapping hole diameter, bolt tightening torque

Material weight calculation: 10+ materials (steel, aluminum, copper, etc.), 5 shapes (round bar, square bar, plate, etc.)

Cutting parameter calculation: spindle speed (RPM), feed rate, cutting speed, supports turning/milling/drilling

Tolerance dictionary & GD&T knowledge base

History and favorites

Target Users

Mechanical design engineers: quickly verify the rationality of tolerance fits in designs

Machining/CNC operators: look up tolerances and cutting parameters on-site

Quality inspection and process personnel: quickly obtain limit deviation values during inspection and acceptance

Mechanical engineering students: learn tolerance fit knowledge, deep dive with GD&T knowledge base

Tolerance Fit Calculator is an offline tool developed for mechanical design, machining, and inspection personnel. Based on the ISO 286 standard, simply enter the nominal diameter, select the tolerance zones and tolerance grades for the hole and shaft, and quickly obtain:

Limit deviations of hole and shaft (upper deviation / lower deviation)

Fit type (clearance fit / transition fit / interference fit)

Maximum clearance and minimum clearance (clearance shown as "+", interference shown as "－")

Input Range & Limits

Diameter range: 0.001 mm ~ 3150 mm

Input digit limit: up to 6 significant digits

Supported Tolerance Zones

Type Tolerance Symbols Hole tolerances A, B, C, CD, D, E, EF, F, FG, G, H, JS, J, K, M, N, P, R, S, T, U, V, X, Y, Z, ZA, ZB, ZC Shaft tolerances a, b, c, cd, d, e, ef, f, fg, g, h, js, j, k, m, n, p, r, s, t, u, v, x, y, z, za, zb, zc Supported Tolerance Grades

All grades IT1 ~ IT18

Special Rules Description (Strictly following ISO 286)

The app has built-in the following standard special rules to ensure accurate and compliant calculations:

Holes A and B are not applicable to nominal sizes of 1 mm or less

Shafts a and b are not applicable to nominal sizes of 1 mm or less

JS 7～JS 11: truncate the decimal part of IT/2 to make it an integer in micrometers (round down)

js 7～js 11: similarly round IT/2 down to an integer in micrometers

Hole J is only supported for grades IT6～IT8

Shaft j is only supported for grades IT5～IT8

Tolerance grades IT14～IT18 are not applicable to nominal sizes of 1 mm or less

For nominal sizes larger than 500 mm, the tolerance values for IT1～IT5 are temporary experimental values (the app will give a prompt)

Core Workflow

Enter the nominal diameter (up to 6 digits)

Tap the tolerance zone buttons to select the hole tolerance (e.g., H) and shaft tolerance (e.g., h)

Download now to make tolerance calculation more efficient and reliable!