ForHosting KIT · Developer Utilities

Calorie deficit calculator

This calorie deficit calculator converts a target weight loss, a planning timeframe in days, and your daily maintenance calories into the average daily calorie deficit and the daily calorie intake that would produce that deficit.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

The model is the classic energy-balance approximation used in coaching worksheets and consumer apps: about 7700 kilocalories per kilogram of body tissue, or 3500 kilocalories per pound, spread evenly across the days you choose. For example, losing five kilograms over seventy days at a twenty-five-hundred-calorie maintenance level implies a total deficit of thirty-eight thousand five hundred kilocalories, a daily deficit of five hundred fifty, and a daily intake near one thousand nine hundred fifty. The engine is fully deterministic finite arithmetic with no network calls, no sampling, and no date-dependent shortcuts. Use it free in the browser for goal setting and education, or call the API at $0.002 per successful request when you need reproducible deficit plans in fitness products, coaching tools, or CI fixtures.

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

What does the calorie deficit calculator cost?

It is free in your browser on this page. Through the API a successful request costs $0.002; invalid inputs are not charged.

How are daily deficit and intake calculated?

total_deficit_kcal = weight_loss × 7700 (kg) or × 3500 (lb); daily_deficit_kcal = total / timeframe_days; daily_intake_kcal = maintenance_calories − daily_deficit_kcal.

What happens if the timeframe is zero or negative?

The input is rejected with invalid_input. A non-positive timeframe cannot define a daily calorie deficit rate.

Does this tool estimate my maintenance calories?

No. You provide maintenance (TDEE). The calculator only turns a weight goal and day count into deficit and intake.

Why might daily intake be very low or negative?

An aggressive loss over a short timeframe can exceed maintenance. The engine reports the arithmetic so apps can warn; it does not give medical advice.

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/health/calorie-deficit

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/health/calorie-deficit \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"weight_loss":5,"timeframe_days":70,"maintenance_calories":2500}'

const res = await fetch("https://api.kit.forhosting.com/health/calorie-deficit", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "weight_loss": 5,
    "timeframe_days": 70,
    "maintenance_calories": 2500
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/health/calorie-deficit",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "weight_loss": 5,
    "timeframe_days": 70,
    "maintenance_calories": 2500
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/health/calorie-deficit", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"weight_loss":5,"timeframe_days":70,"maintenance_calories":2500}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"weight_loss":5,"timeframe_days":70,"maintenance_calories":2500}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/health/calorie-deficit", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "weight_loss": 5,
  "timeframe_days": 70,
  "maintenance_calories": 2500
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "health.calorie_deficit",
  "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_weight_loss`	200
`max_timeframe_days`	3650
`max_maintenance_kcal`	20000

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 →

Run — free