ForHosting KIT · Developer Utilities

Complex number rectangular to polar form

Complex numbers written in rectangular form a plus b i are natural for addition and for reading real and imaginary parts, but multiplication, division, powers, and roots are almost always simpler once the same number is written in polar or trigonometric form.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

This complex number rectangular to polar form calculator accepts the real part a and the imaginary part b, computes the modulus r as the Euclidean length of the vector from the origin to the point (a, b), and computes the principal argument with a two-argument arctangent so every quadrant is correct. The response returns the argument in degrees and in radians, plus ready-to-copy polar and trigonometric display strings of the form r angle theta degrees and r times open parenthesis cosine of theta plus i sine of theta close parenthesis. The origin zero plus zero i is handled as a special case: modulus zero and argument zero degrees by convention, with an is_origin flag so clients do not treat an undefined angle as a silent failure. The same pure logic powers the free browser widget and the prepaid API path, so homework checks and production pipelines never disagree on a quadrant or on the origin edge case.

How to use it

Enter your values in the form above. The tool checks them before calculating and shows the result on the same page.

Check your inputs

Use the labels and units shown next to each field. If something is missing or outside the allowed range, the page points to the field to fix.

Use it again or automate it

Use the browser tool for individual checks and the API when you need the same capability in an automated workflow.

What you can do with it

Get an answer now

Enter one set of values and see the result without building a spreadsheet or script.

Compare scenarios

Change one value at a time and rerun the calculation to understand what affects the result.

Automate repeated work

Use the API when the same calculation needs to run inside your product or workflow.

FAQ

How do I use this capability?

Complete the fields above and run it on this page. The form highlights anything that needs attention.

For developers — API access

Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.

API endpoint

POSThttps://api.kit.forhosting.com/trig/rectangular-to-polar-complex

Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.

Call it from your stack

curl -X POST https://api.kit.forhosting.com/trig/rectangular-to-polar-complex \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"real":3,"imag":4}'

const res = await fetch("https://api.kit.forhosting.com/trig/rectangular-to-polar-complex", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "real": 3,
    "imag": 4
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/trig/rectangular-to-polar-complex",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "real": 3,
    "imag": 4
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/trig/rectangular-to-polar-complex", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"real":3,"imag":4}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"real":3,"imag":4}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/trig/rectangular-to-polar-complex", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "real": 3,
  "imag": 4
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "trig.rectangular_to_polar_complex",
  "status": "queued",
  "_links": {
    "result": "/tasks/tsk_…/result"
  }
}

The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.

Pricing

Per request$0.002

Published price — no tokens, no invented credits. A failed task is never charged.

Errors

HTTP	Code	Meaning
`401`	`unauthorized`	Missing or invalid API key.
`402`	`insufficient_balance`	Your balance doesn't cover the task price.
`404`	`unknown_type`	That task type doesn't exist.
`429`	`rate_limited`	Too many requests. Use the webhook instead of polling.

Read the full KIT documentation →