curl --request POST \
  --url https://api.iotools.cloud/v1/tool/ab-test-sample-size-calculator \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "baselineRate": "5",
  "mdeType": "relative",
  "minimumDetectableEffect": "20",
  "testSides": "two",
  "power": "80",
  "significanceLevel": "0.05",
  "variants": "2",
  "dailyVisitors": ""
}
'

{
  "tool": "ab-test-sample-size-calculator",
  "tool_version": "1.0.2",
  "outputs": {
    "sampleSizePerVariant": "8,155",
    "totalSampleSize": "16,310",
    "estimatedDuration": "Enter daily visitors below to estimate test duration.",
    "details": [
      {
        "metric": "Baseline conversion rate",
        "value": "5.00%"
      },
      {
        "metric": "Target conversion rate (MDE)",
        "value": "6.00%"
      },
      {
        "metric": "Absolute effect",
        "value": "+1.00%"
      },
      {
        "metric": "Relative effect",
        "value": "+20.0%"
      },
      {
        "metric": "Statistical power",
        "value": "80%"
      },
      {
        "metric": "Significance level (α)",
        "value": "0.05"
      },
      {
        "metric": "Test type",
        "value": "Two-sided"
      },
      {
        "metric": "Number of variants (incl. control)",
        "value": "2"
      },
      {
        "metric": "z (significance)",
        "value": "1.960"
      },
      {
        "metric": "z (power)",
        "value": "0.842"
      }
    ],
    "formula": "n = ((z_α + z_β)² × (p1(1-p1) + p2(1-p2))) / (p2 - p1)²\n\nWhere:\n  p1 (baseline)              = 5.00%\n  p2 (target)                = 6.00%\n  z_α (two-sided, α=0.0500) = 1.960\n  z_β (power=80%)             = 0.842\n\nn = ((1.960 + 0.842)² × (0.0500×0.9500 + 0.0600×0.9400)) / (0.0600 - 0.0500)²\n  = 8,155 per variant"
  },
  "credits_used": 5,
  "credits_remaining": null
}