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Ball Grid Array Pitch Calculator

Work out ball grid array pitch instantly with clear inputs, formula shown and shareable results.

About Ball Grid Array Pitch Calculator

A BGA's array span is (grid - 1) times the pitch, and the space between adjacent balls determines how many traces can escape each channel. A 1 mm pitch with 0.5 mm balls leaves 0.5 mm, enough for two 100 micron traces with clearance — which is what sets the PCB layer count.

Formula

BGA geometry

grid = ceil(sqrt(balls)); span = (grid - 1) x pitch; escape channels = (pitch - ball diameter) / (trace + gap)

Worked example

With the default values below, Ball Grid Array Pitch Calculator returns Grid dimension of 28. Change any input above and every figure here is recalculated in your browser.

Inputs used

Ball count
784 balls
Ball pitch
1 mm
Package body size
31 mm
Ball diameter
0.5 mm

Results

Grid dimension
28 balls per side
Array span
27.00 mm
Margin to the package edge
2.00 mm
Traces escaping between balls
2 traces

Step by step

  1. 1Values used
  2. 2BGA geometry
  3. 3Grid dimension= 28 balls per side
  4. 4Array span= 27.00 mm
  5. 5Margin to the package edge= 2.00 mm
  6. 6Traces escaping between balls= 2 traces

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why does pitch drive PCB cost?

Fewer escape channels per row means more layers are needed to route out all the signals, and finer pitch forces microvias and via-in-pad.

What is dog-bone routing?

A short trace from the ball pad to a through-via just outside it. It works down to about 0.8 mm pitch; below that via-in-pad becomes necessary.

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