Documentation sections

BGA Land Pad Calculator

POSThttps://rftools.io/api/py/v1/calculate

Slug bga-land-pad. Calculate BGA land pad diameter, solder mask opening, and escape routing per IPC-7351B, which sizes the land by ball diameter.

Inputs

Send every one of these in inputs, in the units shown. Most are required: a call without one is refused (400) and costs nothing; one the calculator can do without takes the default shown. An input outside its range is still computed and flagged in the provenance.

Inputs of bga-land-pad
Name	Unit	Range	Default	Description
ballPitchnumber	mm	0.3 … 1.27	1	Ball Pitch
ballDiameternumber	mm	0.15 … 0.89	0.6	Ball Diameter
solderMaskDefinednumber	none	0 … 1	0	Solder Mask DefinedOne of: 0 No (NSMD) · 1 Yes (SMD)
viaInPadnumber	none	0 … 1	0	Via-in-PadOne of: 0 No · 1 Yes
ballTypenumber	none	0 … 1	0	Collapsing balls (most BGAs) take a land smaller than the ball; non-collapsing balls one largerOne of: 0 Collapsing · 1 Non-collapsing
landDiameternumber	mm	0.05 … 1.5	0.48	The land diameter on your board, checked against the IPC-7351B land for the ball

Retired, still accepted and ignored with a warning: densityLevel (Density Level (0=Most, 1=Nominal, 2=Least), 2026-10-06).

Outputs

Returned in values, by key. A value that is unbounded or undefined is null.

Outputs of bga-land-pad
Field	Unit	Description
padDiaheadline	mm	Pad Diameter
maskOpening	mm	Solder Mask Opening
maxViaDrill	mm	Max Via Drill (via-in-pad)
channelWidth	mm	Channel Width
escapeRoutes	none	Escape Routes per Channel
maxTraceWidth	mm	Max Trace Width in Channel
stencilAperture	mm	Stencil Aperture
padToPadGap	mm	Pad-to-Pad Gap
ipcLand	mm	The ball diameter less 25, 20 or 15 % (collapsing) or plus 15, 10 or 5 % (non-collapsing), by ball size
landDeviation	mm	How far your land is from the IPC-7351B nominal land, either way
landTolerance	mm	The IPC-7351B land variation either side of the nominal land
landPercent	%	The deviation as a percentage of the land variation; above 100 % the land is outside the IPC-7351B range
compliantLand	mm	The nearer edge of the IPC-7351B land range: the nominal land plus the variation at or above it, minus it below

Calling it

Calculate: one call, the request and response in full, and its errors.
Batch: this calculator with others, or a sweep, in one request.
Solve for a target: the value of one input that brings an output to a target.

curl -X POST https://rftools.io/api/py/v1/calculate \
  -H "X-API-Key: $RFTOOLS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "slug": "bga-land-pad",
    "inputs": {
      "ballPitch": 1,
      "ballDiameter": 0.6,
      "solderMaskDefined": 0,
      "viaInPad": 0,
      "ballType": 0,
      "landDiameter": 0.48
    }
  }'

import rftools

client = rftools.Client()  # reads RFTOOLS_API_KEY, or the key `rftools login` saved

result = client.calculate("bga-land-pad", {
    "ballPitch": 1,
    "ballDiameter": 0.6,
    "solderMaskDefined": 0,
    "viaInPad": 0,
    "ballType": 0,
    "landDiameter": 0.48,
})
print(result.values)
print(result.warnings, result.provenance.formula_ref)

const response = await fetch("https://rftools.io/api/py/v1/calculate", {
  method: "POST",
  headers: {
    "X-API-Key": process.env.RFTOOLS_API_KEY,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "slug": "bga-land-pad",
    "inputs": {
      "ballPitch": 1,
      "ballDiameter": 0.6,
      "solderMaskDefined": 0,
      "viaInPad": 0,
      "ballType": 0,
      "landDiameter": 0.48
    }
  }),
});
console.log(response.status, await response.json());

package main

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
	"os"
)

func main() {
	body := []byte(`{
	  "slug": "bga-land-pad",
	  "inputs": {
	    "ballPitch": 1,
	    "ballDiameter": 0.6,
	    "solderMaskDefined": 0,
	    "viaInPad": 0,
	    "ballType": 0,
	    "landDiameter": 0.48
	  }
	}`)
	req, err := http.NewRequest("POST", "https://rftools.io/api/py/v1/calculate", bytes.NewReader(body))
	if err != nil {
		panic(err)
	}
	req.Header.Set("X-API-Key", os.Getenv("RFTOOLS_API_KEY"))
	req.Header.Set("Content-Type", "application/json")
	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()
	out, _ := io.ReadAll(res.Body)
	fmt.Println(res.Status, string(out))
}

application/json

{
  "slug": "bga-land-pad",
  "values": {
    "padDia": 0.45,
    "maskOpening": 0.55,
    "maxViaDrill": 0,
    "channelWidth": 0.55,
    "escapeRoutes": 2,
    "maxTraceWidth": 0.17500000000000002,
    "stencilAperture": 0.45,
    "padToPadGap": 0.55,
    "ipcLand": 0.45,
    "landDeviation": 0.02999999999999997,
    "landTolerance": 0.05,
    "landPercent": 59.99999999999994,
    "compliantLand": 0.5
  },
  "warnings": [],
  "errors": [],
  "provenance": {
    "method": "calculator:bga-land-pad",
    "version": "api@3f2c1a9b04de",
    "formulaRef": null,
    "assumptions": [],
    "validRange": {
      "status": "inside",
      "bounds": {
        "ballPitch": {
          "min": 0.3,
          "max": 1.27,
          "unit": "mm"
        },
        "ballDiameter": {
          "min": 0.15,
          "max": 0.89,
          "unit": "mm"
        },
        "solderMaskDefined": {
          "min": 0,
          "max": 1,
          "unit": ""
        },
        "viaInPad": {
          "min": 0,
          "max": 1,
          "unit": ""
        },
        "ballType": {
          "min": 0,
          "max": 1,
          "unit": ""
        },
        "landDiameter": {
          "min": 0.05,
          "max": 1.5,
          "unit": "mm"
        }
      },
      "outside": [],
      "model": null
    },
    "computedAt": "2026-09-24T14:05:11.003Z",
    "inputs": {
      "ballPitch": 1,
      "ballDiameter": 0.6,
      "solderMaskDefined": 0,
      "viaInPad": 0,
      "ballType": 0,
      "landDiameter": 0.48
    },
    "seed": null,
    "elapsedSeconds": 0.003
  }
}

{
  "detail": [
    {
      "type": "float_parsing",
      "loc": [
        "body",
        "inputs",
        "ballPitch"
      ],
      "msg": "Input should be a valid number, unable to parse string as a number",
      "input": "abc"
    }
  ]
}

An input sent as text. Nothing was counted.

{
  "detail": "More than 120 requests in 60 seconds from this address.",
  "errorKind": "rate_limited",
  "limit": 120,
  "windowSeconds": 60,
  "upgradeUrl": "https://rftools.io/pricing/"
}

Too many requests in a minute, with Retry-After.

Same inputs on the calculator pageBGA Land Pad Calculator, at these values