PERT critical-path rollup API

Aggregate PERT across a chain of tasks — expected total = Σ te, total sd = √(Σ variance) (variances add along the critical path) — for a project duration with an uncertainty band and per-task breakdown. Answers 'what is the total PERT estimate for these tasks','project duration with uncertainty','combined standard deviation across the critical path'.

Price$0.01per request

MethodPOST

Route/v1/calc/pm-pert-rollup

StatusLive

MIME typeapplication/json

Rate limit120/minute

CacheNo cache

calcpmpertrollupestimatecritical-pathdurationschedule

API URLhttps://x402.hexl.dev/v1/calc/pm-pert-rollup

Integration docs

Example request

{
  "tasks": [
    {
      "optimistic": 2,
      "mostLikely": 4,
      "pessimistic": 9
    },
    {
      "optimistic": 1,
      "mostLikely": 3,
      "pessimistic": 5
    }
  ]
}

Example response

{
  "taskCount": 2,
  "expectedDuration": 7.5,
  "standardDeviation": 1.3437,
  "variance": 1.8056,
  "breakdown": [
    {
      "index": 0,
      "te": 4.5,
      "variance": 1.3611
    },
    {
      "index": 1,
      "te": 3,
      "variance": 0.4444
    }
  ],
  "formula": "E[total] = Σ te ;  sd = √(Σ variance)"
}

Input schema

{
  "type": "object",
  "required": [
    "tasks"
  ],
  "properties": {
    "tasks": {
      "type": "array",
      "description": "Tasks on the path, each {optimistic, mostLikely, pessimistic}",
      "items": {
        "type": "object",
        "required": [
          "optimistic",
          "mostLikely",
          "pessimistic"
        ],
        "properties": {
          "optimistic": {
            "type": "number"
          },
          "mostLikely": {
            "type": "number"
          },
          "pessimistic": {
            "type": "number"
          }
        }
      },
      "examples": [
        [
          {
            "optimistic": 2,
            "mostLikely": 4,
            "pessimistic": 9
          },
          {
            "optimistic": 1,
            "mostLikely": 3,
            "pessimistic": 5
          }
        ]
      ]
    },
    "confidence": {
      "type": "number",
      "description": "Optional CI level: 0.68, 0.80, 0.90, 0.95, or 0.99",
      "examples": [
        0.95
      ]
    }
  }
}

Output schema

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