Alkoc Labs
Home/Tools/Fits & Tolerances Calculator
DESIGN & MANUFACTURING

See how your parts fit.

Turn drawing limits into clearance, interference and an easy-to-read tolerance-zone diagram.

No installation or accountCalculated in this tabCopy or download your result

01 · Your inputs

Choose nominal diameter and classes, for example Ø8 H8/g6. Capital letters identify holes; lowercase letters identify shafts. “M8” here is a hole tolerance class; a metric M8 thread is a different system (e.g. 6H/6g).

Hole
Shaft
Check measured sizes (optional)

Simple inclusive size comparison only. No measurement uncertainty or conformity decision rule.

Decimal point or comma and scientific notation accepted. No thousands separators. Results update as you type.

02 · Your result

Ready to calculate

—
Illustrative geometry; numerical results are listed below.
Calculated values — display rounded to up to 15 significant digits

Inputs stay in this tab. Nothing is uploaded or saved automatically.

Class reference & calculation

Browse all supported classes at this diameter

Deviations in µm; lower < nominal diameter ≤ upper band edge. Values outside 3–120 mm are not extrapolated.

Hole classes · lower / upper deviation
Shaft classes · lower / upper deviation
Formula & assumptions
Limit = nominal + deviation / 1000 (mm)
Minimum clearance = minimum hole − maximum shaft
Maximum clearance = maximum hole − minimum shaft

A positive clearance is a gap. A negative clearance means the shaft is larger than the hole. Overlapping positive and negative outcomes are a transition fit. Zero-only contact is reported separately.

    Sources & limitations

    The bounded numeric reference covers the classes in the supplied Güvenal chart, over 3 through 120 mm (upper boundary included). Band widths follow IT grades; source artwork and OCR are not used as executable data. Verify against your controlled drawing and current ISO 286 for production. The calculator reports dimensional clearance, not whether a fit is appropriate for a particular load, temperature, material or assembly.

    Reference/OCR discrepancies are not copied blindly: E6 at >50–80 mm uses +60/+79 µm (IT6=19); G6 at >80–120 mm uses +12/+34 µm (IT6=22). The original supplied chart has inconsistent figures in these cells. Standard compliance still requires a controlled reference.

    Alkoc Labs calculation engine v0.4.0. Educational and preliminary engineering use; independently verify inputs and results for consequential decisions. Display precision is not measurement uncertainty.

    Keep your next step simple.

    Need a different unit? Open the engineering unit converter. Have a measurement series to present? Open Graph Studio. Browse all tools →

    JSON exports include inputs, units, results, assumptions and source links. They do not contain your files or browser history. Inputs are lost when this tab is closed or reloaded; export anything you need to keep.