ForHosting KIT · Unit converters

Sound power converter

1 watt of acoustic power is exactly 120 dB re 1 pW. Convert sound power between watts, picowatts through megawatts, BTU per hour, erg per second and the level Lw for machine labels, HVAC schedules and lab work. Free in your browser.

Free
Runs in your browser
No sign-up
Your data stays on your device

Run — free How it works & API

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Worked example

If you enter

Value: 1
From: W
To: dB

You get

Result: 120 dB
Converted: 120
Value W: 1
Reference power W: 0

A sound power level converter turns acoustic source power between linear units such as watts, milliwatts, picowatts, BTU per hour, and erg per second, and the ISO sound power level Lw expressed in decibels re one picowatt. Enter a finite magnitude plus a source unit and a target unit; the tool returns the converted value, the SI intermediate in watts, the reference power of one picowatt when the logarithmic path is used, an exact factor for linear pairs, and step-by-step substitution lines you can paste into a lab notebook, HVAC acoustic schedule, or product datasheet. Noise-control engineers comparing fan and machine Lw labels, students converting between watts and dB re 1 pW for homework, and firmware authors mapping sensor-derived power into catalog units all need the same deterministic path.

Which sound-power units are supported and how conversion works

This capability converts among everyday sound-power units that dominate acoustic product labeling, ISO machinery noise reporting, HVAC equipment schedules, and laboratory coursework. The watt is the SI coherent unit of power and the internal hub for every linear conversion: multiply the input by how many watts equal one source unit, then divide by how many watts equal one target unit. Supported SI prefixes are milliwatt, microwatt, nanowatt, picowatt, kilowatt, and megawatt with exact powers of ten.

BTU per hour uses the international-table BTU of 1055.05585262 joules divided by 3600 seconds. Erg per second is exactly 10 to the minus seven watts. Sound power level uses the ISO reference of one picowatt: Lw equals ten times the base-ten logarithm of P divided by one picowatt, and the inverse is P equals one picowatt times ten raised to Lw over ten.

A classic check is one watt of acoustic power corresponding to exactly one hundred twenty decibels re one picowatt. Bare uppercase MW is treated as megawatt so it does not collide with lowercase mW milliwatt after naive lowercasing. Same-unit requests succeed and return the input magnitude.

Conversion from a linear unit into dB requires strictly positive power so clients never receive negative infinity or NaN. This tool deliberately stays on the sound-power axis: it does not convert sound pressure level re twenty micropascals, sound intensity in watts per square metre, A-weighting, or free-field spherical spreading, which are different acoustic quantities with different reference levels and dimensions.

Practical tips, limits, and when to use this landing

Prefer sending bare numbers for value when you control the client; string numbers are accepted only when they match a strict finite numeric pattern without currency symbols or thousand separators. Round-trip checks are straightforward for linear pairs: convert A to B and B back to A and confirm you recover the original within the published twelve-decimal rounding. For the logarithmic path, convert one watt to dB and expect one hundred twenty, then convert one hundred twenty dB back to one watt.

When teaching ISO Lw, pair classic examples such as one picowatt to zero dB, one milliwatt to ninety dB, and one watt to one hundred twenty dB re one picowatt. Stay inside the absolute range so intermediate watt values cannot overflow. This landing targets people searching for a sound power level converter, watts to dB re 1 pW, acoustic power BTU/h, or Lw calculator online; it is not a general multi-quantity unit converter, not a sound pressure level (SPL) tool, not a sound intensity calculator, and not a room-acoustics predictor.

What you can do with it

Machine and fan Lw labeling

Manufacturers convert lab watt readings into dB re 1 pW so datasheets, cartons, and ISO machinery noise tables use the same sound power level as catalog SKUs.

HVAC acoustic schedules

Engineers convert mixed W, mW, and BTU/h equipment powers into one unit before comparing alternate air-handling units or summing plant acoustic loads.

Acoustics homework and lab notes

Students convert between watts and Lw in dB re 1 pW with deterministic steps they can compare against hand calculations before submission.

FAQ

What is sound power level in dB re 1 pW?

Sound power level Lw is ten times the base-ten logarithm of acoustic power P divided by the ISO reference of one picowatt (10⁻¹² W). One watt equals 120 dB re 1 pW.

Is this the same as sound pressure level (SPL)?

No. This tool converts sound power and Lw re 1 pW. Sound pressure level uses a different reference (20 µPa) and is a field quantity, not source power.

Can I convert zero watts to dB?

No. Non-positive linear power is rejected when the target is dB because log10 of zero or a negative number is not defined for a finite Lw.

Is the sound power converter free?

The browser tool is free and runs locally.

How is BTU per hour converted to watts?

The converter uses the international-table BTU of 1055.05585262 joules spread over 3600 seconds. Enter your BTU per hour figure and pick watts, or the level in dB re 1 pW, as the target.

Related tools

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/conv/sound-power

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/conv/sound-power \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"value":1,"from":"W","to":"dB"}'

const res = await fetch("https://api.kit.forhosting.com/conv/sound-power", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "value": 1,
    "from": "W",
    "to": "dB"
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/conv/sound-power",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "value": 1,
    "from": "W",
    "to": "dB"
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/sound-power", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"value":1,"from":"W","to":"dB"}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"value":1,"from":"W","to":"dB"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/sound-power", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "value": 1,
  "from": "W",
  "to": "dB"
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "conv.sound_power",
  "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_abs 1000000000000

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.

Technical notes

Unknown unit names fail with a clear invalid_input error instead of silent wrong factors, and non-positive linear power is rejected when the target is dB because the logarithm of zero or a negative number is not defined.

Which sound-power units are supported and how conversion works

Common aliases are accepted: W, watt, and watts; mW and milliwatt; µW, uW, and microwatt; nW and nanowatt; pW and picowatt; kW and kilowatt; MW and megawatt; dB, Lw, dB re 1 pW, and sound power level; BTU/h, BTU/hr, and BTU per hour; erg/s and ergs per second. If the name is not on that list the solver rejects the request with invalid_input naming the bad field and listing supported units.

How to call the API and read the response

Value must be a finite number or a strict numeric string within absolute limits of one trillion. Wire this into dashboards, mobile clients, or batch jobs that already hold a sound-power reading and only need a second unit for display, labeling, or regulatory comparison without shipping conversion tables in every app binary. Send a JSON body with three required fields: value (aliases power, amount, P, Lw, and sound_power), from (aliases from_unit, unit_from, and source), and to (aliases to_unit, unit_to, and target). From and to must resolve to supported unit names after alias normalization. On success the response echoes the rounded input value, canonical from and to labels, result and converted set to the same rounded target magnitude, value_W as the SI intermediate in watts, unit as the target label, factor as the from-to linear multiplier or null when either side is dB, formula as the short equation string for the linear or logarithmic path, reference_power_W as one times ten to the minus twelve, message as an English summary, steps as ordered substitution lines, and supported_units as the ten canonical identifiers. Failed validation—missing fields, non-finite numbers, values outside absolute limits, an unknown unit name, or a non-positive linear magnitude when targeting dB—returns invalid_input and is never charged. Pricing is a flat $0.002 per successful request with unit item and zero marginal unit price.

Practical tips, limits, and when to use this landing

Normalize display labels on your side if you need locale-specific spellings—this API always returns short canonical tokens such as W, mW, µW, nW, pW, kW, MW, dB, BTU/h, and erg/s so automated tests stay stable. Prefer this capability when both endpoints are among the supported sound-power units and you need deterministic factors, ISO Lw arithmetic, and step strings; if you need intensity I equals P over four pi r squared, use a dedicated intensity calculator such as phys.sound_intensity instead. Failed tasks that return invalid_input do not consume prepaid balance, which keeps exploratory scripts cheap when clients deliberately probe unknown unit names or zero power into dB.

Technical questions

What happens with unknown unit names?

The API returns invalid_input naming the field and listing supported units: W, mW, µW, nW, pW, kW, MW, dB, BTU/h, and erg/s.

Read the full KIT documentation →

Run — free

Worked example

Which sound-power units are supported and how conversion works

Practical tips, limits, and when to use this landing

What you can do with it

Machine and fan Lw labeling

HVAC acoustic schedules

Acoustics homework and lab notes

FAQ

Related tools

For developers — API access

API endpoint

Call it from your stack

Example request

Example response

Pricing

Limits

Errors

Technical notes

Which sound-power units are supported and how conversion works

How to call the API and read the response

Practical tips, limits, and when to use this landing

Technical questions

thank you