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PCB Calculator Methodology & References

The tool suite uses explicit engineering approximations. Internal dimensional storage is millimetres; copper weight uses 1 oz = 1.378 mil = 35.0012 µm. Temperature rise converts as an interval, so a 10 °C rise is an 18 °F rise, while 20 °C ambient is 68 °F.

Model boundaries

Copper resistivity is 1.724×10⁻⁸ Ω·m at 20 °C and the temperature coefficient is 0.00393/°C. Trace resistance is evaluated at ambient plus rise. Via current applies the internal trace coefficient to barrel cross-section as a heuristic; it is not an IPC-certified via model. Symmetric stripline assumes equal dielectric gaps. Thermal relief uses copper conductivity 401 W/(m·K) and ignores spreading. Panel placement is a uniform rectangular grid, not an optimal nesting solver.

PCB Trace Width Calculator

I = k × ΔT^0.44 × A^0.725; w = A / t. k = 0.048 external or 0.024 internal; A and t in mil units.

This legacy IPC-2221 power law is an early sizing model, not an IPC-2152 thermal simulation. Nearby copper, enclosure, airflow and neck-downs change actual heating.

PCB Current Capacity Calculator

I = k × ΔT^0.44 × (w_mil × t_mil)^0.725.

Capacity describes an isolated empirical baseline, not a current rating or a fuse trip current.

PCB Via Current Calculator

A = π[(d/2+p)² − (d/2)²]; R = ρL/A; array R = R/N. Screening I = N × 0.024 × ΔT^0.44 × A_mil²^0.725.

Mapping the trace power law to barrel area is a heuristic, not a validated IPC via rating. Linear current scaling assumes identical, equally fed vias; mutual heating and unequal sharing are omitted.

PCB Impedance Calculator

Microstrip Z0 = 87/√(εr+1.41) × ln[5.98h/(0.8w+t)]. Symmetric stripline Z0 = 60/√εr × ln[1.9b/(0.8w+t)], b = 2h+t.

Estimate only. Simple closed-form formulas omit solder mask, trapezoidal etching, copper roughness, frequency dispersion and nearby conductors. Symmetric stripline only; h is the copper-surface distance to either plane.

Differential Impedance Calculator

Microstrip Zdiff ≈ 2Z0[1−0.48 exp(−0.96s/h)]. Symmetric stripline Zdiff ≈ 2Z0[1−0.347 exp(−2.9s/b)], b = 2h+t (coupling scale approximated as 2h).

Estimate only for edge-coupled symmetric pairs. Not a solver for broadside pairs, asymmetric routing, discontinuities, connectors or reference-plane voids.

PCB Pad Size Calculator

Pad diameter D = d + 2r. Total area = πD²/4. Copper annulus area = π(D²−d²)/4.

Nominal geometry only. Drill wander, etching, fabrication class, assembly requirements and fabrication tolerances must be budgeted separately.

PCB Thermal Relief Calculator

A_total = Nwt; R_electrical = ρL/A_total; R_thermal = L/(κA_total), κ = 401 W/(m·K), ρ = 1.724×10⁻⁸ Ω·m at 20 °C.

One-dimensional copper conduction only. Not a pad temperature, solderability, thermal-via or board-to-ambient thermal model. Spoke spreading and contact effects are omitted.

PCB Panelization Calculator

Nx = floor[(panel_width−2rail+spacing)/(board_width+spacing)], similarly Ny. Count = NxNy; utilization = count × board area / gross panel area.

Tests two uniform rectangular orientations, not mixed-orientation packing. Fabricator tooling, V-score restrictions, tabs, fiducials and assembly clearances can reduce the usable count.

Clearance & Creepage Checklist

Clearance is the shortest distance through air. Creepage is the shortest distance along an insulating surface. No universal voltage-only formula establishes either requirement.

This is guidance, not an IEC table lookup or compliance calculator. No numerical safe spacing is generated. Confirm against the applicable edition of IEC 60664-1 and the relevant product standard.

Primary references and further verification