Machining Tolerances Calculator v1

Price: £20.00 (£20.00 Inc. VAT)
Machining tolerance calculator


Machining tolerances refer to the maximum and minimum metal conditions that need to be applied to the design of mating components that will ensure a particular class of fit:
loose, loose-running, tight, drive, etc.

The two predominant design standards for this technology are ISO (286-1:2010) and ANSI (B4.1 & 2), both of which have different tolerance ranges and classes of fit.


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The machining tolerance calculator identifies the maximum and minimum diameters (machining tolerances) for mating holes and shafts according to the above ISO and ANSI design standards.

Whilst it is usual to select a designated tolerance combination to achieve a specified class of fit, Limits and Fits does not enforce such limitations. You may select any standard or non-standard fit for any combination of shaft and hole size variation you wish. When selecting non-standard fits, the machining tolerances calculator will notify you if it finds a match with a standard ISO or ANSI fit.

The diameters accommodated in the machining tolerances calculator are 0 to 500mm (0 to 20ins).
You may enter the diameter in millimetres or inches and the machining tolerance dimensions are provided in both millimetres and inches.

For help using this calculator see Technical Help

Calculation Options

The standard machining tolerance fit options available are listed as follows:

ISO Specifications

Loose Running (Hole or Shaft based)

Free Running (Hole or Shaft based)

Close Running (Hole or Shaft based)

Sliding (Hole or Shaft based)

Locational Clearance (Hole or Shaft based)

Locational Transition (Hole or Shaft based)

Locational Transition (tight) (Hole or Shaft based)

Locational Interference (Hole or Shaft based)

Medium Drive (Hole or Shaft based)

Force (Hole or Shaft based)

ANSI Specifications

RC1 to 9

LC1 to 11

LT1 to 6

LN1 to 3

FN1 to 5

Universal Combination

However, you can pick any combination of fits between A(a) to ZC(zc) and 01 to 16

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