PCB Impedance & Stackup Calculator

Results are for reference. Confirm the final stackup and impedance requirements with our engineers. Method & sources

PCB Information

Copper layersBoard thickness (mm)Outer copper weightInner copper weightBlind / buried vias requestTrace display units

Copper weights are nominal equivalents of the thicknesses shown. Calculate applies board settings; unchanged settings keep your layer edits.

Selecting a signal layer automatically sets its nearest upper and lower reference planes. You can select other reference layers for a special design. Changing the signal layer resets both references.

Select	Name	Target (Ω)	Signal layer	Impedance model	Upper ref.	Lower ref.	Starting width (mil)	Edge gap (mil)	Ground separation (mil)
								—	—

Section parameters · Signal 1

Base − top width (mil)Reference configuration

Solder mask · outer surface Include explicitly specified coating

Enter the coating thickness and Dk.

Outer traces use the entered base and opposite-face widths, with the base facing the substrate. Zero width difference gives a rectangle.

Width bounds & copper thickness

Minimum width (mil)Maximum width (mil)Custom finished outer copper (mm)Custom inner copper (mm)

PCB Stack-up

3 structures

Stack-up 1 : 04161H01-2116 · 4 layers · 1.6 mm

Selected for engineering review

1.520 mmPhysical thickness

Swipe tables to view trace dimensions and material values →

Set your impedance requirements above, then select Calculate to see trace width and nominal impedance.

Physical stackup, material specifications, Dk and thickness in millimeters.
Physical layer	Material type	Specification / material	Dk	Thickness (mm)
L1Signal	Copper Foil	Final Copper1oz(0.33oz+Plating)Specification: 1	—	0.0350
D1	PP / Prepreg	2116 Thickness0.125 RC 57%Specification: 2116	4.20	0.1250
L2Lower referenceD2L3	CoreIncludes copper	1.2 incl. copper H/HSpecification: incl. copper	4.50	1.2000
D3	PP / Prepreg	2116 Thickness0.125 RC 57%Specification: 2116	4.20	0.1250
L4	Copper Foil	Final Copper1oz(0.33oz+Plating)Specification: 1	—	0.0350
Total stackup thickness				1.5200 mm

Schematic · thickness in mm. Core includes copper.

Edit materials & layer thicknesses

Candidate name

Physical layer sum 1.5200 mmRequested board 1.6 mmCalculations use editable physical layers.

Layer	Material	Dk
L1 ·	Finished copper	—
D1 ·	Official product
L2 ·	Finished copper	—
D2 ·	Official product
L3 ·	Finished copper	—
D3 ·	Official product
L4 ·	Finished copper	—

Stack-up 2 : 04161H02-1080 · 4 layers · 1.6 mm

1.524 mmPhysical thickness

Swipe tables to view trace dimensions and material values →

Set your impedance requirements above, then select Calculate to see trace width and nominal impedance.

Physical stackup, material specifications, Dk and thickness in millimeters.
Physical layer	Material type	Specification / material	Dk	Thickness (mm)
L1Signal	Copper Foil	Final Copper1oz(0.5oz+Plating)Specification: H	—	0.0350
D1	PP / Prepreg	1080 Thickness0.077 RC 67%Specification: 1080	4.00	0.0770
L2Lower referenceD2L3	CoreIncludes copper	1.3 incl. copper H/HSpecification: incl. copper	4.50	1.3000
D3	PP / Prepreg	1080 Thickness0.077 RC 67%Specification: 1080	4.00	0.0770
L4	Copper Foil	Final Copper1oz(0.5oz+Plating)Specification: H	—	0.0350
Total stackup thickness				1.5240 mm

Schematic · thickness in mm. Core includes copper.

Edit materials & layer thicknesses

Candidate name

Physical layer sum 1.5240 mmRequested board 1.6 mmCalculations use editable physical layers.

Layer	Material	Dk
L1 ·	Finished copper	—
D1 ·	Official product
L2 ·	Finished copper	—
D2 ·	Official product
L3 ·	Finished copper	—
D3 ·	Official product
L4 ·	Finished copper	—

Stack-up 3 : 04161H05-7628 · 4 layers · 1.6 mm

1.470 mmPhysical thickness

Swipe tables to view trace dimensions and material values →

Set your impedance requirements above, then select Calculate to see trace width and nominal impedance.

Physical stackup, material specifications, Dk and thickness in millimeters.
Physical layer	Material type	Specification / material	Dk	Thickness (mm)
L1Signal	Copper Foil	Final Copper1oz(0.33oz+Plating)Specification: 1	—	0.0350
D1	PP / Prepreg	7628 Thickness0.2 RC 48%Specification: 7628	4.50	0.2000
L2Lower referenceD2L3	CoreIncludes copper	1.0 incl. copper H/HSpecification: incl. copper	4.50	1.0000
D3	PP / Prepreg	7628 Thickness0.2 RC 48%Specification: 7628	4.50	0.2000
L4	Copper Foil	Final Copper1oz(0.33oz+Plating)Specification: 1	—	0.0350
Total stackup thickness				1.4700 mm

Schematic · thickness in mm. Core includes copper.

Edit materials & layer thicknesses

Candidate name

Physical layer sum 1.4700 mmRequested board 1.6 mmCalculations use editable physical layers.

Layer	Material	Dk
L1 ·	Finished copper	—
D1 ·	Official product
L2 ·	Finished copper	—
D2 ·	Official product
L3 ·	Finished copper	—
D3 ·	Official product
L4 ·	Finished copper	—

Detailed parameter comparison

Compare stackups

Current editable structures

Comparison baselineShow differences only

Parameter	Stack-up 1 04161H01-2116 · 4 layers · 1.6 mmBaseline	Stack-up 2 04161H02-1080 · 4 layers · 1.6 mm	Stack-up 3 04161H05-7628 · 4 layers · 1.6 mm
Physical thickness mm · sum of copper & dielectric	1.5200	1.5240Different from baseline	1.4700Different from baseline
Outer dielectric H Top / bottom · mm	0.1250 / 0.1250	0.0770 / 0.0770Different from baseline	0.2000 / 0.2000Different from baseline
Outer copper T Top / bottom · mm	0.0350 / 0.0350	0.0350 / 0.0350	0.0350 / 0.0350
Outer dielectric Dk Top / bottom · each sheet; no Dk averaging	4.2 / 4.2	4 / 4Different from baseline	4.5 / 4.5Different from baseline
Outer material / test condition Top / bottom · layer-provided metadata	Top: 2116 Thickness0.125 RC 57% (imported-a1f984ce-material-2) · frequency Not provided · test Not provided · No Dk overrideBottom: 2116 Thickness0.125 RC 57% (imported-a1f984ce-material-4) · frequency Not provided · test Not provided · No Dk override	Top: 1080 Thickness0.077 RC 67% (imported-f53e2673-material-2) · frequency Not provided · test Not provided · No Dk overrideBottom: 1080 Thickness0.077 RC 67% (imported-f53e2673-material-4) · frequency Not provided · test Not provided · No Dk overrideDifferent from baseline	Top: 7628 Thickness0.2 RC 48% (imported-53684e4f-material-2) · frequency Not provided · test Not provided · No Dk overrideBottom: 7628 Thickness0.2 RC 48% (imported-53684e4f-material-4) · frequency Not provided · test Not provided · No Dk overrideDifferent from baseline

Impedance differences below 0.005 Ω are treated as equal in this comparison.

Calculate to compare impedance and trace dimensions for each requirement.

Use a public stackup reference

Public geometry reference

Replaces the current candidates and applies the selected board settings.

Material library · add custom material

How are PCB impedance and trace width estimated?

Estimate nominal single-ended, differential and coplanar PCB impedance, or find trace width for a target impedance. Select the signal and reference layers, then supply dielectric Dk and finished cross-section dimensions. Results support stackup planning; production dimensions and impedance tolerance require project-specific engineering confirmation.

Free online calculator. JavaScript and an internet connection are required.

Method, assumptions and sources

Calculation method

Calculations use a two-dimensional quasistatic cross-section model. Supported geometries use boundary-element or finite-element field calculations; matching requests may reuse precomputed solver curves or saved results. In trace-width mode, the solver searches within the selected bounds while respecting the chosen spacing constraints.

How should I choose reference layers?

The signal layer automatically selects its nearest available reference layers. For a special design, choose other reference layers and specify the roles of intervening copper. Finished dielectric spacing, not overall board thickness alone, determines the trace-to-reference distance.

What does the estimate exclude?

Only the declared cross-section is modelled. Copper roughness, conductor and dielectric losses, frequency-dependent Dk dispersion, and 3D via discontinuities are not simulated. Reference stackups and the HDI choice are starting points for review, not production approval.

What should I confirm before fabrication?

Confirm the laminate construction and Dk, pressed dielectric thicknesses, finished copper and etched trace dimensions, reference-plane continuity, and required impedance tolerance with your engineer. Send the selected stackup and requirements using Request Stackup Review.

Physical references

These references explain the underlying physics. They do not independently validate or certify this calculator.

PCB Information

Impedance requirements

PCB Stack-up

Compare stackups

How are PCB impedance and trace width estimated?

Calculation method

How should I choose reference layers?

What does the estimate exclude?

What should I confirm before fabrication?

Physical references

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