ForHosting KIT · Developer Utilities

Calculate Recommended Daily Water Intake by Weight

This daily water intake calculator turns body weight and activity level into a practical hydration estimate.

● BetaFree · in your browser

Use it from WebAPIEmailTelegramApp soon

It applies a transparent baseline of 35 milliliters per kilogram, then adjusts the result for low, moderate, or high activity. The response includes both milliliters and liters, along with the multiplier used, so the recommendation is easy to display, explain, and reproduce. It is intended as general wellness guidance rather than individualized medical advice, and API requests start at $0.002.

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 formula does the calculator use?

It multiplies weight in kilograms by 35 ml, then applies an activity multiplier: 1.00 for low, 1.15 for moderate, or 1.30 for high activity.

Why does activity change the recommendation?

Physical activity can increase fluid loss, so the moderate and high settings raise the weight-based baseline by fifteen and thirty percent respectively.

Which weight unit should I enter?

Enter body weight in kilograms as a positive finite number. Zero, negative, missing, and non-numeric values return an invalid_input error.

What units does the result include?

The result includes the recommended daily intake in whole milliliters and in liters rounded to three decimal places.

Is the result medical advice?

No. It is a general wellness estimate and does not account for medical conditions, medications, pregnancy, climate, altitude, or individual sweat rate.

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/calc2/water-intake-recommend

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/calc2/water-intake-recommend \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"weight_kg":70,"activity_level":"moderate"}'

const res = await fetch("https://api.kit.forhosting.com/calc2/water-intake-recommend", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "weight_kg": 70,
    "activity_level": "moderate"
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/calc2/water-intake-recommend",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "weight_kg": 70,
    "activity_level": "moderate"
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/calc2/water-intake-recommend", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"weight_kg":70,"activity_level":"moderate"}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"weight_kg":70,"activity_level":"moderate"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/calc2/water-intake-recommend", 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_kg": 70,
  "activity_level": "moderate"
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "calc2.water_intake_recommend",
  "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 →