Is GOST pipe the same size as European pipe?

Rarely exactly. Of the 70 outside diameters in GOST 8732-2025 and the 35 in EN 10220:2002 (Series 1), only 9 are the same number. Another 9 are near-twins that differ by 0.1 to 0.4 mm — a Russian 76 mm against a European 76.1 mm, for instance. They are separate entries in separate catalogues, not one diameter written two ways.

Does GOST 8732 have a 168.3 mm pipe?

No. It lists 168 mm. The European and American series both use 168.3 mm at that size, and GOST substitutes the rounded integer — as it does at 9 sizes across the range. The difference is small, but the two are different designations and the wall series attached to them are independent.

How is a GOST pipe specified if there is no DN?

By outside diameter and wall thickness directly. A GOST designation names the two numbers and the length, with no nominal-bore column anywhere in the standard. The DN-to-OD tables published against GOST are trade convention rather than standards text.

Why do Russian and Chinese diameters look so similar?

Because both kept an older European metric tradition. A number of the Russian domestic diameters do appear in the European register — but in its non-preferred tiers, having been demoted rather than dropped. China's domestic B series has the same shape and the same origin.

Can I substitute a GOST pipe for a European one?

It is a specification question rather than a fit question at these gaps. The diameters are within a few tenths of a millimetre, but the wall series, the mass and the bore are set independently by each standard, so matching the outside diameter does not make two pipes equivalent. Match the standard, not just the number.

GOST and the European Series

The two registers look interchangeable in a catalogue and almost never are. GOST 8732-2025 lists 70 outside diameters and EN 10220:2002 (Series 1) lists 35. Exactly 9 are the same number. Another 9 come within 0.4 mm of each other without ever meeting.

The Near-Misses

These are the pairs that cause the trouble. In each case GOST carries a round integer and the European series carries a decimal a few tenths away — and GOST does not list the European figure at all, so there is nothing to fall back to.

Every GOST 8732-2025 diameter within 0.5 mm of an EN 10220:2002 (Series 1) diameter without equalling it. Computed from 9892 compiled wall rows.
GOST 8732 (mm)	EN 10220 (mm)	Gap (mm)
76	76.1	0.1
89	88.9	0.1
114	114.3	0.3
140	139.7	0.3
168	168.3	0.3
219	219.1	0.1
324	323.9	0.1
356	355.6	0.4
406	406.4	0.4

The gaps run from 0.1 to 0.4 mm. Small — and worth being precise about rather than alarmed by. At these distances the issue is usually not that the pipe will not physically go together; it is that the two are different products with independently set walls, so agreeing on the outside diameter settles less than it appears to.

Where They Do Agree

9 diameters are common to both: 21.3, 26.9, 33.7, 42.4, 48.3, 60.3, 273, 457, 508 mm. The small end of that list is the British gas-thread inheritance that both traditions drew on, and the large end is where every series converges on the American diameters. The middle of the range — the sizes most piping actually uses — is where they diverge.

At 2 of those sizes — 42.4 and 60.3 mm — GOST carries the European figure and a rounded integer beside it, as two ordinary neighbouring entries. Those are not traps: both diameters are there to be ordered. It is only where the European figure is absent altogether, as in the table above, that a near match becomes a substitution.

That is the same pattern the European series shows against ASME: agreement at the top of the range, divergence below it, for the reason set out in why 2½-inch pipe has three different diameters.

GOST Does Not Have a Nominal Bore Column

The comparison above is between diameter lists rather than between nominal sizes, and that is not a presentational choice. GOST designates a pipe as outside diameter, wall thickness and length — there is no DN column in the standard at all. A designation names the numbers directly.

So a DN-to-GOST conversion table is a trade convention someone has built on top of the standard, not something the standard publishes. We keep those two kinds of claim apart deliberately; what DN actually measures sets out why it matters, and GOST pipe dimensions carries the full table.

A Domestic Series Beside an International One

GOST carries a domestic set alongside a foreign-trade set, and the domestic diameters are not Soviet inventions — a number of them turn up in the European register, in its non-preferred tiers. They are a shared older European metric tradition that EN demoted rather than deleted.

China runs the same structure independently, and rather more confusingly, because there the pipe and its own fittings can default to opposite sides of the split: China’s A and B series. For what every one of these documents publishes side by side, see pipe standards compared, and for which of them applies where, pipe standards by country.

Frequently Asked Questions

Is GOST pipe the same size as European pipe?: Rarely exactly. Of the 70 outside diameters in GOST 8732-2025 and the 35 in EN 10220:2002 (Series 1), only 9 are the same number. Another 9 are near-twins that differ by 0.1 to 0.4 mm — a Russian 76 mm against a European 76.1 mm, for instance. They are separate entries in separate catalogues, not one diameter written two ways.
Does GOST 8732 have a 168.3 mm pipe?: No. It lists 168 mm. The European and American series both use 168.3 mm at that size, and GOST substitutes the rounded integer — as it does at 9 sizes across the range. The difference is small, but the two are different designations and the wall series attached to them are independent.
How is a GOST pipe specified if there is no DN?: By outside diameter and wall thickness directly. A GOST designation names the two numbers and the length, with no nominal-bore column anywhere in the standard. The DN-to-OD tables published against GOST are trade convention rather than standards text.
Why do Russian and Chinese diameters look so similar?: Because both kept an older European metric tradition. A number of the Russian domestic diameters do appear in the European register — but in its non-preferred tiers, having been demoted rather than dropped. China's domestic B series has the same shape and the same origin.
Can I substitute a GOST pipe for a European one?: It is a specification question rather than a fit question at these gaps. The diameters are within a few tenths of a millimetre, but the wall series, the mass and the bore are set independently by each standard, so matching the outside diameter does not make two pipes equivalent. Match the standard, not just the number.