Quick answer
Compression Class 1 or Class 2 does not mean the same pressure in every market. RAL-GZ 387, British hosiery specifications and common US mmHg descriptions use different categories, test systems and product terminology. Buyers should not convert a class name by label alone. A defensible specification states the product type, exact pressure interval, measurement location, test method, conditioning, size and target market, then verifies the finished sock against that requirement.
A sourcing brief that says only “Class 2 compression sock” is incomplete. A German clinic, British distributor and US wellness retailer can attach different numerical expectations to the same words. Even when two labels show a similar mmHg range, the test apparatus, measurement point, garment category and tolerances may differ.
This article explains specification control rather than individual pressure selection. Wearers with medical conditions or symptoms should follow qualified clinical advice. Brands should use the medical-device versus wellness claims guide before turning a technical pressure result into a treatment statement.
Why class names cannot travel alone
Class numbers are shorthand within a named system. Remove the system name and the number loses context. A buyer must also distinguish medical compression hosiery, anti-embolism hosiery and support products because standards can place them in different categories.
“Medical grade” is even less precise when no standard is named. It can imply pressure, quality, professional use or regulatory status without proving any of them. Replace the phrase with an auditable specification.
Understand the RAL-GZ 387 framework
The German quality assurance framework RAL-GZ 387 publishes four compression classes measured at the ankle reference point: Class I 18–21 mmHg, Class II 23–32 mmHg, Class III 34–46 mmHg and Class IV at least 49 mmHg. The framework includes more than a pressure table; material, construction, sizing and testing requirements matter.
Do not place an RAL class on packaging merely because one prototype result falls inside the interval. Use of a quality mark or certification claim requires authorization and fulfillment of the applicable scheme, not visual imitation.
Read British specifications as their own system
BS 661210:2018+A1:2022 covers graduated compression hosiery, anti-embolism hosiery and graduated support hosiery using specified test approaches and product categories. Its class language should be quoted with the standard edition and category.
A pressure range copied from a secondary chart can omit tolerances, conditioning, sampling and method details. Buyers who need compliance with a British specification should obtain and work from the current official document or a qualified laboratory plan.
Treat US mmHg ranges as labeled specifications
In the United States, the market commonly describes products by intervals such as 15–20 or 20–30 mmHg, but that commercial convention is not one universal compression-class standard. Suppliers can use different equipment or protocols unless the buyer defines them.
Ask exactly where the stated pressure is measured, whether it describes a nominal target or acceptance band, how graduated zones are evaluated and which sizes were tested. A familiar interval on a package does not automatically establish device classification or equivalence with RAL or British classes.
Name the test method and apparatus
Pressure is not observed directly while the sock lies flat; it is estimated or measured under defined extension and geometry using a method and instrument. HOSY and HATRA-related approaches have different procedures and reporting conventions. Results should identify equipment, calibration, conditioning, size, circumference or form and measurement locations.
The graduated compression verification guide provides a practical report checklist. Do not compare values from unidentified methods as if they were the same dataset.
Keep pressure profile and class distinct
A class describes a pressure category within a system; graduation describes how pressure changes along the leg. A sock can meet an ankle interval yet fail the intended profile higher on the calf. Conversely, a smoothly graduated sample may not fall within the labeled class.
The graduated versus uniform compression guide helps teams specify the direction and checkpoints. Both range and profile belong in the approval criteria.
Build size coverage into validation
Different sizes use different stitch counts, dimensions and extension on the body. One middle-size report may not support the complete size run. Use a risk-based matrix covering the smallest and largest dimensions, any wide-calf or tall variants and additional sizes where construction changes.
The compression sock size-chart guide explains body measurements and consumer selection. Pressure validation must use the approved garment and intended circumference assumptions, not a generic size name.
Write a market-specific tech pack
The pressure section should state: target country, product category, named standard and edition, range and reference point, gradient requirements, method, conditioning, selected sizes, repetitions, tolerance and retest plan. Include the exact package wording under approval control.
Use the compression sock tech-pack guide to connect those requirements with yarn, knit program and measurement revisions. A class change may require construction redevelopment, not just a label edit.
Compare supplier reports before quotations
Request a redacted example report showing the supplier's usual method and traceability. Confirm whether quoted testing is internal, external or certification-related, and whether it covers development, bulk lots or both. Laboratories and schemes should be checked directly rather than accepted from a logo on a PDF.
A buyer should also define what happens when results fail: adjustment, resampling, retest, lot hold or label change. Never choose a more convenient label after testing simply to make a failed product appear compliant.
Cross-market specification checklist
- Name the country, product category, standard and edition.
- State mmHg interval, reference point and graduated profile.
- Identify apparatus, procedure, conditioning and calibration.
- Define size coverage, sample count, tolerances and retest rules.
- Keep claims and class marks subject to regulatory or scheme approval.
- Revalidate relevant material, program and size changes.
Request a market-specific pressure specification review with your target standard, sizes and intended label. NextCompSox can align sampling and manufacturing records with the agreed method without claiming that one class name is universal.
Buyer takeaway
A class number without its system is not a complete requirement. Specify the market, product category, mmHg interval, point, profile and method; then verify the finished size range. That discipline prevents translation errors and gives retailers a pressure statement they can trace to real product evidence.
Frequently asked questions
Is Compression Class 1 the same in Germany and the UK?
No. Class numbers must be read within the named standard, product category and edition. Do not convert them by number alone.
Is 20–30 mmHg always Class 2?
No. It is a commonly used commercial range, but class boundaries and terminology differ across systems and markets.
What does RAL Class II mean?
RAL publishes Class II as 23–32 mmHg at the defined ankle reference point within its complete RAL-GZ 387 framework. Scheme requirements extend beyond that number.
Can an OEM factory choose the pressure test method?
The buyer and responsible business should approve a method appropriate to the target standard and claim. The report must identify the actual method used.
Does one pressure report cover every size?
Not automatically. Size construction and extension can change results, so the validation matrix should justify coverage across the size range.