Try the ISO 286 Fit & Tolerance Calculator
Calculate ISO 286 limits and fits for sizes up to 500 mm: enter the nominal size and fits like H7/g6 and get hole and shaft limits.
- Free to use
- No signup
- Nothing to install
- Runs in your browser
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The ISO 286 Fit & Tolerance Calculator with sample data entered and the result showing.
What is the ISO 286 Fit & Tolerance Calculator?
The ISO system of limits and fits describes how tightly a shaft sits in a hole using a letter for the fundamental deviation and a number for the tolerance grade — H7 for a hole, g6 for a shaft. This calculator turns that notation into numbers: enter a nominal size up to 500 mm and any hole/shaft pair (for example H7/g6 or K7/h6) and it returns the lower and upper limit of each part, the fit type (clearance, transition or interference), the minimum and maximum clearance or interference in micrometres, and a diagram of the two tolerance zones against the zero line.
The values come from the ISO 286 standard tables: IT grades IT4–IT14, shaft letters d e f g h js k m n p and hole letters D E F G H JS K M N P, with the Δ correction applied to K, M, N (≤ IT8) and P (≤ IT7). A list of the preferred fits (H7/g6 sliding, H7/h6 locational, H7/k6 and H7/n6 transition, H7/p6 press) fills the form in one click, and an IT-grade table shows the tolerance width for your size range.
3 steps to your result
Open the tool and follow along. Nothing to install.
What you get
Standard IT grades and fundamental deviations — e.g. 25 H7 = +21/0 µm, 25 g6 = −7/−20 µm.
Clearance, transition or interference with min/max values.
See hole and shaft zones relative to the zero line.
H7/g6, H8/f7, H9/d9, H7/h6, H7/k6, H7/n6, H7/p6 and shaft-basis equivalents.
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Used for
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How it compares
A plain look at this tool next to the usual alternative.
| This engineering calculator | Desktop software | |
|---|---|---|
| Install | Nothing to install | Usually an app or program to install |
| Account | No signup | Depends on the product |
| Cost | Free to use | Free or paid, depends on the product |
| Where it runs | In your browser tab | On your computer |
Questions people ask
What does H7/g6 mean?
A hole to H7 (lower deviation zero, IT7 tolerance) paired with a shaft to g6 (small negative deviation, IT6 tolerance) — a sliding clearance fit.
How do I know if a fit is clearance or interference?
If the smallest hole is larger than the largest shaft it is clearance; if the largest hole is smaller than the smallest shaft it is interference; otherwise transition.
Which sizes are covered?
0 to 500 mm. Letters r, s, t, u and larger grades are not included.
Are the numbers exact?
They reproduce the standard's tabulated values for the included letters and grades.
How do I use the ISO 286 Fit & Tolerance Calculator?
1. Enter the nominal size in mm. 2. Type the hole and shaft fits, or click a preferred fit. 3. Read the limits and fit type. 4. Dimension the drawing with the resulting limit sizes.
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Limits and fits for any size: hole/shaft deviations, clearance or interference. Free to use.
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