ForHosting KIT · Developer Utilities

Blended rate calculator

A blended interest rate is the single figure that represents several loans at once: each loan's annual rate is weighted by its outstanding balance, so a large cheap mortgage pulls the average down and a small expensive card pulls it up only in proportion to what you still owe.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

Borrowers look up this number when they refinance, when a lender asks for the average cost of debt, or when they compare a new consolidation offer against the mix they already hold. This blended rate calculator accepts a list of loans with balances and annual percentage rates, returns the weighted average, and rejects a zero total balance instead of dividing by nothing. The same pure parse logic powers the free browser widget and the API path, so spreadsheets, coaching apps, and edge workers all see identical figures without model tokens or outbound network calls. Use it when you need a deterministic cost-of-debt snapshot, not a full amortization table.

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/fin/blended-rate

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/fin/blended-rate \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"loans":[{"name":"Mortgage","balance":200000,"rate":4.25},{"name":"Auto loan","balance":15000,"rate":6.9},{"name":"Personal loan","balance":5000,"rate":11.5}]}'

const res = await fetch("https://api.kit.forhosting.com/fin/blended-rate", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "loans": [
      {
        "name": "Mortgage",
        "balance": 200000,
        "rate": 4.25
      },
      {
        "name": "Auto loan",
        "balance": 15000,
        "rate": 6.9
      },
      {
        "name": "Personal loan",
        "balance": 5000,
        "rate": 11.5
      }
    ]
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/fin/blended-rate",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "loans": [
        {
            "name": "Mortgage",
            "balance": 200000,
            "rate": 4.25
        },
        {
            "name": "Auto loan",
            "balance": 15000,
            "rate": 6.9
        },
        {
            "name": "Personal loan",
            "balance": 5000,
            "rate": 11.5
        }
    ]
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/fin/blended-rate", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"loans":[{"name":"Mortgage","balance":200000,"rate":4.25},{"name":"Auto loan","balance":15000,"rate":6.9},{"name":"Personal loan","balance":5000,"rate":11.5}]}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"loans":[{"name":"Mortgage","balance":200000,"rate":4.25},{"name":"Auto loan","balance":15000,"rate":6.9},{"name":"Personal loan","balance":5000,"rate":11.5}]}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/fin/blended-rate", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "loans": [
    {
      "name": "Mortgage",
      "balance": 200000,
      "rate": 4.25
    },
    {
      "name": "Auto loan",
      "balance": 15000,
      "rate": 6.9
    },
    {
      "name": "Personal loan",
      "balance": 5000,
      "rate": 11.5
    }
  ]
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "fin.blended_rate",
  "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.

Limits

max_items 100

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 →