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Surface resistivity and ESD

Surface resistivity shows how easily charge moves across a material. Learn what makes a material ESD-safe and how to read the numbers.

3 min read · Updated October 11, 2026 · Numbers update live from our materials database.

What it means in practice

Surface resistivity describes how easily electric charge travels across a material’s surface. Most plastics are excellent insulators, so static charge builds up and stays put. When it finally jumps, the spark (electrostatic discharge, or ESD) can damage sensitive electronics or, in rare cases, ignite flammable vapours or dust.

Key takeaways

  • Surface resistivity shows how easily charge moves across a surface, in ohms per square.
  • Static-dissipative materials drain charge slowly and safely, usually what electronics need.
  • Think in powers of ten: the exponent matters, the leading digit rarely does.
  • Print settings and humidity can shift results, so measure your own parts.

Materials are grouped loosely into three bands:

  • Insulative: very high resistivity. Charge stays where it lands.
  • Static-dissipative: moderate resistivity. Charge drains away slowly and safely. This is usually what you want around electronics.
  • Conductive: low resistivity. Charge moves fast. Useful for grounding paths and shielding, but a fast discharge can itself be a risk to some components.

Good to know

Exact band limits differ between standards. Our ESD-safe badge uses 10⁹ Ω/sq or lower.

Typical uses for ESD-safe prints include PCB fixtures and test jigs, trays and carriers for components, assembly-line tooling, and housings for sensors.

How it’s measured

Electrodes, often a centre disc with a ring around it, are placed on the surface. A set voltage is applied and the current is measured.

  • Standards: ASTM D257, IEC 62631-3-2, and ANSI/ESD STM11.11 for ESD work.
  • Units: ohms per square (Ω/sq). Values are written in powers of ten, such as 10⁶ or 10⁹.

How to read and compare it

  • Think in powers of ten. 10⁶ and 10⁹ differ by a factor of a thousand. Small differences in the exponent matter; small differences in the leading digit rarely do.
  • “Greater than” values such as “>10¹³” mean the meter hit its limit. The material is an insulator; the exact value is unknown.
  • Resistivity vs resistance. Surface resistivity (Ω/sq) and surface resistance (Ω) are related but not the same. Do not compare them directly.
  • Print settings matter. ESD filaments get their conductivity from carbon additives. Print temperature, speed and surface finish can shift the result, and top surfaces may read differently from sides. Measure your own parts.
  • Humidity. Some antistatic materials work better in humid air. Check the test conditions.
  • Not a safety certificate. For work in explosive atmospheres or regulated ESD areas, validate the finished part to your site’s requirements.

Surface resistivity (Ω/sq)

Quoted in ohms per square.

Surface resistance (Ω)

A related reading, but not the same. Do not compare the two directly.

Watch out

A datasheet value is a starting point, not proof. For regulated ESD areas or explosive atmospheres, validate the finished part.

In our catalog

Resistivity is stored as text, often as a range or a “greater than” value, so we count materials rather than show a numeric range:

  • ESD-safe materials: 28
  • ESD-safe filaments: 22
  • ESD-safe resins: 2
  • ESD-safe high-performance materials: 7

Stiffness of ESD-safe materials: 1,121–15,000 MPa (median 2,930 MPa, 26 materials).

For design advice, see ESD and electronics parts.

See all ESD-safe materials 28 materials