Enter a diameter with its tolerance class, or a tolerance range, and we will work out the rest.
Click a cell to calculate. General / Common / Preferred are selection levels for design (which class to consider first); they do not mean the classes are interchangeable — whether one can replace another depends on the size limits (see "these also comply" in the result).
This is a first orientation, not an engineering approval — the drawing, the materials and the actual working conditions decide. Prefer the hole-basis system (hole fixed at H, vary the shaft); use the shaft-basis system (shaft fixed at h, vary the hole) when the shaft is a ready-made part such as a dowel pin or ground shafting.
| Fit | Type | Typical use |
|---|---|---|
| H7/g6 | Clearance | Precision sliding fit: very small clearance, slides freely with almost no play. Precision guides, reciprocating piston rods and guide bushings, dowel pins and fixture holes that are plugged in and out often yet must stay centred. |
| H7/h6 | Clearance | Sliding / locational fit with zero minimum clearance; can be assembled by hand. Stationary joints that must be centred, or slow sliding: removable dowel pins in fixture holes, couplings on shafts, replaceable guide bushings. |
| H7/js6 | Transition | The loosest transition fit, averaging close to zero clearance. Assembled by hand or with a mallet; for parts that must be centred yet removable: gears and pulleys on shafts (torque carried by a key). |
| H7/k6 | Transition | The most widely used transition fit, with a small chance of interference. Assembled with light hammer blows, removable and well centred: gears, pulleys, couplings, rolling-bearing inner rings on shafts (light loads). |
| H7/m6 | Transition | A transition fit on the tight side, mostly a slight interference. The standard pairing for press-in dowel pins — ISO 8734 / DIN 6325 plus-tolerance pins are m6, used with a reamed H7 hole; for moulds, dies and fixtures that are rarely dismantled and must not work loose. |
| H7/n6 | Transition | The tightest transition fit, almost always an interference. Needs a press and is not normally dismantled: fixed pins, bushings, gear rims. |
| H7/p6 | Interference | Light interference: held by pressing in but unable to transmit much torque on its own (add a key). Bushings pressed into housings, locating sleeves, heavily loaded bearing outer rings in housings. |
| H7/r6 | Interference | Medium interference: transmits moderate torque, assembled with a press; dismantling damages the parts. |
| H7/s6 | Interference | Medium interference: transmits a certain torque and axial force; assembled with a press or by heating. Permanent joints of steel and cast-iron parts, gear rims on hubs. |
| H7/u6 | Interference | Heavy interference: shrink or expansion fit; the interference transmits high torque and the joint is regarded as permanent. Railway wheels on axles, heavy-duty couplings. |
| H7/f7 | Clearance | Close running fit. Plain bearings at medium speed and load, gearbox shafts and bushings, rotating parts that need an oil film. |
| H8/f7 | Clearance | Close running fit of ordinary accuracy; used like H7/f7 but with a less demanding hole: shafts and bushings in general machinery, pump and fan shafts. |
| H8/h7 | Clearance | Locational fit of ordinary accuracy with zero minimum clearance. Dowel pins and holes without high accuracy demands, removable sleeves. |
| H8/h8 | Clearance | Zero-clearance sliding fit of ordinary accuracy, hole and shaft of the same grade. Non-critical locating and guiding. |
| H8/e8 | Clearance | Easy running fit. High-speed or multi-bearing shafts, long shafts with wide spans, plain bearings that need a thicker oil film. |
| H9/h9 | Clearance | Sliding / locational fit of ordinary accuracy. Loose connection of parallel keys in keyways (key width h9), non-critical sleeves on shafts. |
| H9/d9 | Clearance | Loose running fit. Pulleys, loosely running parts, places with thermal expansion or dirt. |
| H11/h11 | Clearance | Loose location with wide tolerances: locating stamped and cast parts, non-fitting dimensions. |
| H11/c11 | Clearance | Very loose running fit: farm machinery, joints exposed to contamination or heat, hinges, clevis pins and forks (the pin diameter of ISO 2341 clevis pins is h11). |
| G7/h6 | Clearance | Precision sliding fit on the shaft-basis system, equivalent to H7/g6. Use G7 for the hole when the shaft is a standard part (h6 ground shafting, dowel pins). |
| F8/h7 | Clearance | General running fit on the shaft-basis system, equivalent to H8/f7. With a standard h7 shaft or pin, make the bushing bore F8. |
| K7/h6 | Transition | General transition fit on the shaft-basis system, equivalent to H7/k6. K7 is common for the housing bore of rolling-bearing outer rings. |
| N7/h6 | Transition | Tight transition fit on the shaft-basis system, equivalent to H7/n6. Bearing outer rings fixed in the housing, locating sleeves pressed into housings. |
| P7/h6 | Interference | Light interference fit on the shaft-basis system, equivalent to H7/p6. Housing bores for pressed-in bushings are often P7. |
For the actual assembly, also check material, surface finish and operating conditions.
The letter is the fundamental deviation — which side of the nominal size the tolerance zone lies on: a–g (shafts) / A–G (holes) lie further from nominal the earlier the letter, giving more clearance; h / H sit exactly on the nominal size (upper deviation 0 / lower deviation 0) and are the datum; j, js, k, m, n straddle the nominal size and give transition fits; from p onward the fit gets tighter and tighter — interference. The number is the tolerance grade IT — how wide the zone is: IT5–IT6 fine grinding, IT7 reaming / fine turning, IT8–IT9 ordinary turning and milling, IT11 and above rough machining and stamping.
Uppercase is a hole, lowercase is a shaft. A hole and a shaft with the same letter lie on opposite sides of the nominal size, which is why H7/h6 gives a minimum clearance of exactly 0.
On a drawing, Ø8 h7, 8h7 and 8(h7) are the same thing; written out it is 8(0/-0.015). SFP product specifications always show the written-out numbers, so you can compare them with your drawing without a table; to look for stock by tolerance class, paste the written-out form into the catalog search.
8h7 means "diameter 8, never larger than 8 and at most 0.015 smaller". The part must measure between 7.985 and 8.000 mm, written 8(0/-0.015). The letter h means "only on the minus side" and the number 7 says how much variation is allowed; the smaller the number, the more precise.
Uppercase is a hole (inside diameter, e.g. H7) and lowercase is a shaft (outside diameter, e.g. h7). With the same letter, hole and shaft lie on opposite sides of the nominal size: an 8H7 hole can only be larger than 8, an 8h7 shaft only smaller.
Just type 3(0/-0.014). The calculator tells you it is h8 and lists which other classes also comply (such as h7 or g6). Those listed first are closest to your range; price and lead time depend separately on material, size and stock — a tighter tolerance is not always more expensive, and the grade that is in stock is often the fastest and cheapest.
For this one dimension, yes — provided the nominal size and size range are the same and both are shaft tolerance h. In that case the h7 zone lies entirely inside h8, so the size always passes. The reverse does not work: h8 parts cannot be supplied against an h7 drawing. Note that material, length, hardness and surface treatment are separate requirements; passing on tolerance does not make them pass.
We still need material, length, quantity and any other drawing requirements (surface treatment, hardness). Click "Copy RFQ text", paste it into a message to us, add those items and we can quote.
Compare the size limits, not how similar the codes look. It is acceptable only if the supplier's range lies entirely inside the range the drawing allows; enter both in the calculator and you will see at once.
The pin diameter alone is not enough; you also need the size and tolerance of the hole. Once you have both ranges, look at the table of common fits: a clearance fit can be pushed in and pulled out, an interference fit has to be pressed in.
Ordinary dowel pins are minus tolerance (0/-0.02) or h6 / h7; in an H7 hole they can be removed and refitted repeatedly. For a press-in joint use plus-tolerance m6 pins (ISO 8734 / DIN 6325), which are slightly tight in an H7 hole.
The table follows ISO 286-1 and was checked cell by cell on 2026-08-26 against three independent sources: a public reference site, our own ISO 286-1 formula engine, and an in-house table already verified against real engineering drawings. All 6,674 cells agree, with 0 errors. Coverage is shafts a–z and holes A–Z, IT1–IT13, 0–500 mm; anything outside it (cd/ef/fg/za/zb/zc, above 500 mm, above IT13) is reported as not found rather than guessed. The full method and the known issues are on the "Data sources and verification" page.
Values follow ISO 286-1; the table was cross-checked cell by cell against three independent sources on 2026-08-26 (6,674 cells agree, 0 errors). Coverage: shafts a–z and the corresponding uppercase holes, IT1–IT13, nominal sizes 0–500 mm. cd/ef/fg/za/zb/zc, sizes above 500 mm and grades above IT13 are not included: the tool reports "not found" and never extrapolates. Data sources and verification →