FR-4 vs G11
Composite · grade comparison
FR-4 and G11 are both composite grades. G11 is the stronger of the two: tensile strength 340 MPa (49.3 ksi) against 310 MPa (45 ksi) for FR-4, about 10% more. G11 runs hotter in service (180°C vs 130°C continuous). On the shop floor, FR-4 sits in a lower cost tier (standard, $$) than G11 (premium, $$$).
FR-4Choose it when cost is the deciding factor.
G11Choose it when strength drives the design, or when the part sees heat.
FR-4 vs G11: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all composite grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all composite grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Shear Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Compressive Strength
Compressive Modulus
Flexural Strength
Flexural Modulus
Shear Strength
Izod Impact, Notched
Fracture Toughness (K_IC)
Hardness, Shore D
Same in both: Elastic (Young's) Modulus 22 GPa3.2 Msi · Elongation at Break 1.8% · Hardness, Rockwell M 110 HRM
Physical
Density and transition temperatures.
Glass Transition (Tg)
Water Absorption (24 h)
Same in both: Density 1.85 g/cm³0.07 lb/in³ · Water Absorption (Saturation) 0.35%
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Limiting Oxygen Index
Max Service Temperature (short-term)
Heat Deflection Temp. @ 1.8 MPa
Same in both: Specific Heat Capacity 1,100 J/kg·K0.26 BTU/lb·°F
Electrical
Conductivity and insulation.
Dielectric Strength
Dielectric Constant (1 MHz)
Same in both: Electrical Resistivity 1×10¹² Ω·m3.94×10¹⁹ µΩ·in · Dissipation Factor (1 MHz) 0.02 · Volume Resistivity 1×10¹⁴ Ω·cm · Surface Resistivity 1×10¹³ Ω · Comparative Tracking Index (CTI) 200 V
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
UV / Weathering Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Weldability
Formability (cold)
Same in both: Machinability 45 / 100 · Polishability 30 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 0%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Thermal Diffusivity
Same in both: Specific Stiffness (E / density) 11.9 MN·m/kg · Thermal Shock Resistance Index 0
Strength versus weight
Yield strength against density for every composite grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | FR-4 | G11 |
|---|---|---|
| Default condition | Epoxy Matrix | Epoxy Matrix |
| Relative cost | $$ Standard | $$$ Premium |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Both are offered for CNC machining and Sheet metal. Both take the same 1 finish: Painting.
FR-4 vs G11 — frequently asked
Is G11 stronger than FR-4?
Yes. G11 has a typical tensile strength of 340 MPa (49.3 ksi) against 310 MPa (45 ksi) for FR-4 — about 10% more.
Which is cheaper, FR-4 or G11?
FR-4 is the lower-cost material: it sits in the standard tier ($$) while G11 is premium ($$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
When should I choose FR-4 over G11?
Pick FR-4 when cost is the deciding factor. Pick G11 when strength drives the design, or when the part sees heat.
Ready to make it?
Upload a CAD file and FabDigit prices the part in FR-4 and G11 side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.