Medical

Compression Sock mmHg Specs for OEM Buyers

Published: 2026-07-02By ZheSock TeamReading time: 7 min

Buying a compression sock is not the same as buying a basic sport sock. A label may say 15 to 20 mmHg or 20 to 30 mmHg, but actual pressure depends on machine setup, yarn denier, stitch length, size grading, wash state, and test method. OEM buyers need those details written into the spec before sampling starts. If not, the first bulk lot can miss the claimed band. Then you face relabeling, returns, and trouble with retail or medical channel requirements.

Table of Contents

1. What compression sock mmHg specs mean in OEM buying
2. How factories measure and verify mmHg in development and bulk production
3. Which technical specs change pressure the most
4. Choosing the right mmHg band for your sales channel and target price
5. What to ask for in sampling, MOQ, packaging, and production planning
6. Quality control, AQL, and compliance points that matter for medical channel socks

What compression sock mmHg specs mean in OEM buying

Compression sock mmHg specs describe the pressure a sock applies to the leg, measured in millimeters of mercury. In OEM buying, the number is usually a range, not one exact figure. Common bands are 8 to 15 mmHg, 15 to 20 mmHg, 20 to 30 mmHg, and 30 to 40 mmHg.

The pressure should be highest at the ankle and lower at the calf. That is the core rule of graduated compression. For knee highs, many factories and labs check pressure at the ankle point, often called the B point in hosiery testing. If the ankle reading is inside range but the calf drop is too small, the sock can still feel wrong in wear.

For OEM buyers, compression sock mmHg specs must match a full size matrix. A package claim of 20 to 30 mmHg means very little unless the factory also lists ankle circumference, calf circumference, foot length, leg length, and the leg form used for testing. Example. A medium may be built for ankle 20 to 23 cm, calf 32 to 38 cm, foot length 23 to 25 cm, and sock leg length 34 to 38 cm. Change one of those numbers and the pressure changes.

8 to 15 mmHg. Light support for daily wear and entry travel styles.
15 to 20 mmHg. The most common band for private label ecommerce and airport retail.
20 to 30 mmHg. Common in pharmacy and medical adjacent channels. Needs tighter size control.
30 to 40 mmHg. Harder to fit and harder to keep stable in bulk.

Approve the pressure band by size before you approve the package art. Do it in that order.

How factories measure and verify mmHg in development and bulk production

There is no shortcut. Ask the factory to state the test method, test point, leg form, and wash condition. Two labs can test the same sock and report different numbers if they use different forms or different preconditioning.

A practical approval flow for OEM compression socks usually has four checkpoints.

First development sample. Fit check and estimated pressure check.
Revised sample. Pressure adjusted by yarn count, stitch length, or size grading.
Pre production sample. Final approved construction before bulk.
Bulk inline and final inspection. Pressure checked from packed production lots.

For a 20 to 30 mmHg knee high, a serious supplier should keep records by size, not just for one reference size. A normal control plan is 3 to 5 pairs tested per size during sample stage, then 5 to 8 pairs per production lot during bulk stage, depending on order size. If the order is 10,000 pairs across 3 sizes, ask for readings for S, M, and L. Not just M.

A common internal tolerance in commercial programs is plus or minus 2 mmHg at the ankle test point. Some factories allow plus or minus 3 mmHg for lower compression bands. Put that tolerance on the approved spec sheet. Without a written tolerance, every dispute turns into an argument.

Ask for these records before bulk release.

Leg form circumference used for each size.
Pressure reading point, usually the ankle.
Wash state, unwashed or after 5 home laundry cycles.
Room conditioning before test, normally standard textile lab conditions.
Actual readings for the full approved size set.

If a factory only says, "we can make 20 to 30 mmHg," that is not a spec. It is a sales line.

Which technical specs change pressure the most

Many buyers start with fiber content. That matters, but pressure comes from the whole structure. On a compression sock, the main variables are machine diameter, needle count, covered spandex denier, ground yarn denier, plating ratio, stitch length by zone, cuff construction, and size grading.

Common production setups for knee high compression socks in Datang use single cylinder hosiery machines in 168N, 176N, or 200N. Needle count often falls between 144 and 200, depending on sock size and pattern complexity. For plain medical styles, 168N or 176N is common. For a finer surface and smaller size steps, some factories use 200N. Higher needle count can improve appearance and hand feel, but it does not create higher compression by itself.

Yarn setup usually affects pressure more.

Ground yarn. Nylon 70D/24F, 100D/36F, or cotton blend wrapped constructions.
Elastic component. Covered spandex 20D, 40D, or 70D, with single or double plating.
Foot bottom reinforcement. Often added with extra nylon plating. This changes stretch in the foot area more than in the leg.
Cuff section. Often built with a tighter 1x1 or 3x1 rib to reduce slipping.

Socks are not usually quoted by GSM the way T shirts are, but pair weight still matters. A plain nylon compression knee high often weighs about 45 to 75 grams per pair, depending on size and pressure band. Cotton rich versions often run 60 to 90 grams per pair. If pair weight swings too much inside one lot, pressure consistency often swings too.

Size grading is where many private label programs fail. A broad range like "M fits calf 30 to 42 cm" looks simple for retail, but it is hard to keep pressure stable across that span. Narrower grading works better.

S. Ankle 18 to 21 cm, calf 28 to 34 cm.
M. Ankle 20 to 23 cm, calf 32 to 38 cm.
L. Ankle 22 to 25 cm, calf 36 to 42 cm.

That gives the factory a real target. It also cuts returns.

Choosing the right mmHg band for your sales channel and target price

The right band depends on where the sock will be sold and what the package will claim. For mass ecommerce, travel retail, and gift channels, 8 to 15 mmHg and 15 to 20 mmHg are usually easier to size and easier to sell. For pharmacy and medical adjacent channels, 20 to 30 mmHg is common, but sampling, testing, and size control cost more.

As a workable FOB China guide for plain custom knee high compression socks, based on total orders of 3,000 to 10,000 pairs, these are typical price ranges.

8 to 15 mmHg. USD 0.85 to 1.25 per pair.
15 to 20 mmHg. USD 1.00 to 1.55 per pair.
20 to 30 mmHg. USD 1.35 to 2.20 per pair.
30 to 40 mmHg. Often USD 1.90 to 3.20 per pair, with more sample revisions.

Those prices are for standard nylon and spandex constructions with simple header card or OPP bag packing. Add about USD 0.08 to 0.20 for custom printed paper inserts, and about USD 0.12 to 0.35 for retail boxes. Costs rise if the style uses cotton rich yarns, skin tone dye matching, jacquard branding, or anti slip sole printing.

Lead time also changes with pressure level. A basic 15 to 20 mmHg private label order may need 7 to 12 days for the first sample and 25 to 35 days for bulk after approval. A 20 to 30 mmHg program often needs 10 to 18 days for the first sample, then one more revision cycle of 7 to 10 days if pressure needs tuning. Bulk is often 30 to 40 days after final approval and deposit.

Short version. Higher compression costs more, takes longer, and gives you less room for broad sizing.

What to ask for in sampling, MOQ, packaging, and production planning

Compression socks need a more detailed tech pack than ordinary socks. Artwork is not enough. The factory should receive the target mmHg band, size chart by ankle and calf, sock height, foot size range, yarn preference, toe construction, color references, package format, and market destination.

MOQ depends on the stage of the project. A factory may accept 100 pairs for a paid development lot on certain standard constructions. That is useful when the buyer wants wear testing or product photos before placing a full order. For repeat bulk production with stable pressure output, many programs start at 1,000 pairs per size per color. Some run at 3,000 pairs per color across sizes if the machine setup and yarn are fixed.

A realistic planning range looks like this.

Development sample. 7 to 14 days for 15 to 20 mmHg.
Higher compression sample. 10 to 18 days for 20 to 30 mmHg.
Sample revision. Add 7 to 10 days if pressure or fit needs correction.
Bulk production. 25 to 40 days after sample approval and deposit.
Peak season buffer. Add 5 to 10 days around major holiday shipping periods.

Packing matters too. Compression cuffs can deform if pairs are folded too tightly, banded too hard, or packed in cartons that are too small. Ask the supplier how the cuff is packed and how long the socks sit under compression before shipment. A practical carton count for knee highs is often 100 to 200 pairs per export carton, depending on pack style. Mixed size cartons increase picking mistakes, so many importers ask for one size per inner carton and clear carton marks by size, color, and PO number.

Before you place the PO, ask for these items.

Approved pre production sample with measured pressure values.
Final spec sheet with machine setup, yarn counts, pair weight, and size chart.
Packaging standard that does not crush the cuff.
AQL plan and final inspection report format.

If those items are missing, the order is not ready for bulk.

Quality control, AQL, and compliance points that matter for medical channel socks

Appearance inspection is only part of the job. A compression sock can look clean and still fail on pressure, size, recovery, or pairing. Buyers selling into medical, pharmacy, or wellness channels should ask for a control plan that covers visual defects and performance checks.

A common final inspection level for export socks is AQL 2.5 for major defects and AQL 4.0 for minor defects. For compression programs, many buyers also define extra performance checkpoints outside the visual AQL count. Examples include pressure reading by size, cuff recovery after wash, and length tolerance. That matters because pressure complaints are rarely caught by appearance inspection alone.

Useful bulk QC points include the following.

Pressure test on sampled pairs from each size run.
Pair weight check against approved sample, often within plus or minus 5 percent.
Length tolerance, often within plus or minus 1.5 to 2.0 cm for knee highs.
Cuff opening and recovery check after repeated stretch.
Toe closure inspection, especially on hand linked or Rosso toe sections, to reduce irritation complaints.
Shade review by dye lot, important for white and skin tone styles.
Needle line, hole, dropped stitch, and yarn contamination inspection.

For compliance, stick to records the factory can actually provide. Common documents include OEKO-TEX for harmful substance control, BSCI or Sedex for social audit requirements, ISO 9001 for quality management systems, and GOTS or GRS only when the material program really uses certified organic or recycled inputs. If the product enters the EU in a medical device category that needs CE, that has to be handled at the product and document level. Do not print medical outcome claims that the factory or brand owner cannot support.

One more point. Ask whether the pressure test was done on finished socks before packing, and whether the reading came from unwashed goods or after 5 washes. Many bulk disputes start with that missing detail.

Frequently Asked Questions

Is 15 to 20 mmHg enough for most private label compression sock programs?

Yes. For non clinical retail programs, 15 to 20 mmHg is the most common band. It works well for travel, office wear, long shift work, and general ecommerce. It usually fits a wider customer range than 20 to 30 mmHg and causes fewer complaints about tightness. You still need a real ankle and calf size chart for each size.

Can a factory match an exact number like 22 mmHg?

Usually no in bulk production. Buy by range, not by one exact number. Commercial orders are normally built around bands such as 15 to 20 mmHg or 20 to 30 mmHg. A practical ankle tolerance is often plus or minus 2 mmHg. Ask the factory to write the target band, test point, leg form, and tolerance on the approved spec sheet.

What is the normal MOQ for custom compression socks?

For bulk OEM orders, 1,000 pairs per size per color is a common starting point for stable output. Some programs run at 3,000 pairs per color across several sizes. For development or pilot runs, certain standard constructions can start at 100 pairs, but the unit cost is higher and yarn choices are more limited.

How long do sampling and production take for compression socks?

A first custom sample usually takes 7 to 14 days for 15 to 20 mmHg styles. For 20 to 30 mmHg, allow 10 to 18 days. If pressure needs correction, add 7 to 10 days for a revised sample. Bulk production usually takes 25 to 40 days after sample approval and deposit. Add 5 to 10 days in peak season.

Which materials are most common in compression sock manufacturing?

Most commercial compression socks use nylon and covered spandex because the stretch and recovery are more predictable. Common setups include nylon 70D or 100D ground yarn with 20D, 40D, or 70D covered spandex, using single or double plating. Cotton rich versions are possible, but the structure has to be controlled more tightly to hit the same mmHg band.

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