Suture Size Chart — USP Sizes & Materials

USP suture sizes (11-0 to 5) with diameter range, materials and typical use.

About this calculator

A suture size chart converts USP (United States Pharmacopeia) gauge to actual thread diameter in millimetres. USP sutures use a direct-then-inverted scale: sizes 0, 1, 2, 3, 4, 5 get larger; sizes 2-0, 3-0, 4-0, 5-0, 6-0, 7-0, 8-0, 9-0, 10-0 get smaller. Each "0" added means thinner.

Choosing suture size is a balance between tissue holding strength (favours larger) and visible scarring (favours smaller). For most adult skin closure on the face: 5-0 or 6-0. For body skin: 3-0 or 4-0. For deep fascia: 0 or 1. For microsurgery / ophthalmology: 9-0 or 10-0 — finer than a human hair.

Worked example

Inputs: Suture selection by anatomical site

  1. Face/cosmetic skin closure: 5-0 or 6-0 monofilament (e.g. nylon, polypropylene)
  2. Scalp/limb skin: 3-0 or 4-0 monofilament
  3. Subcutaneous tissue: 3-0 or 4-0 absorbable (e.g. polyglactin)
  4. Fascia/muscle closure: 0 or 1 absorbable (PDS or polyglactin)
  5. Vascular anastomosis: 5-0 to 7-0 polypropylene

Frequently asked questions

Absorbable or non-absorbable suture?

Absorbable (Vicryl, Monocryl, PDS, catgut): used internally where the suture only needs to hold for 1–6 weeks until healing. No removal required — the body breaks them down. Non-absorbable (silk, nylon, polypropylene): used externally for skin closure (removed at 5–14 days) and internally for permanent prosthetic anchoring (mesh, valves). Skin suture in low-tension cosmetic areas can also be absorbable for patient comfort (no removal visit).

When to remove sutures?

Face: 4–7 days. Scalp: 7–10 days. Trunk: 7–14 days. Limbs: 7–14 days (longer for joints/high-tension areas). Hands and feet: 10–14 days. Removing too early causes wound dehiscence; too late causes "railroad track" scarring. Use Steri-Strips after removal if the wound is at risk of reopening.

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