Z-score ↔ percentile converter API

Convert a z-score to a percentile via the standard-normal CDF, or a percentile to its z-score via the inverse normal (Acklam approximation). Auditable: echoes the cumulative probability. Answers 'what percentile is z=1.5','z-score for the 90th percentile','convert percentile to z'.

Price$0.01per request

MethodPOST

Route/v1/calc/stat-z-percentile

StatusLive

MIME typeapplication/json

Rate limit120/minute

CacheNo cache

calcstatisticsz-scorepercentilenormalinverse-normalquantileconvert

API URLhttps://x402.hexl.dev/v1/calc/stat-z-percentile

Integration docs

Example request

{
  "z": 1.5
}

Example response

{
  "mode": "z->percentile",
  "z": 1.5,
  "percentile": 93.3193,
  "cumulativeProbability": 0.933193,
  "interpretation": "z=1.5 is at the 93.32th percentile."
}

Input schema

{
  "type": "object",
  "required": [],
  "properties": {
    "z": {
      "type": "number",
      "description": "supply z to get a percentile",
      "examples": [
        1.5
      ]
    },
    "percentile": {
      "type": "number",
      "description": "supply a percentile (0-100) to get z",
      "examples": [
        97.5
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}