Power to lift load calculator
Raising 50 kg by 10 m in 5 seconds takes 4903.325 J of work and 980.665 W of average power under standard gravity. Use it to size a hoist, winch or lift motor. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Mass
- 50
- Height
- 10
- Time
- 5
- G
- 9.80665
- Work joules
- 4,903.325
- Power watts
- 980.665
Raising a load against gravity takes work equal to mass times gravity times height, and delivering that work in a fixed time sets the average mechanical power you need from a hoist, winch, elevator, or human effort. Engineering homework, machine sizing sketches, warehouse lift checks, crane duty estimates, and contest problems all ask the same practical question: how many watts to lift this mass this high in this many seconds.
What power to lift means and which quantities you need to send
In classical mechanics, the gravitational work to raise a mass m through a vertical height h near a constant g is W equals m times g times h. Average power over the lift interval is that work divided by the time t available for the motion: P equals W over t, or P equals m g h over t.
When mass is in kilograms, g in metres per second squared, height in metres, and time in seconds, power comes out in watts, the SI unit used on motor nameplates, datasheets, and textbook answers. Search intent clusters around phrases such as power to lift load calculator, power to raise a mass, hoist power from mass height and time, lifting power formula, watts to lift kg, crane power estimate, P equals mgh over t, and average power for vertical lift.
People want a numeric watt answer they can check against a worksheet, size a motor sketch, or feed into a larger pipeline—not only a reminder that potential energy exists. Units stay consistent with whatever coherent set you chose: SI inputs yield true watts; any coherent quartet yields a coherent power in the same system. This landing targets the lift-from-mass-height-time intent, which is distinct from generic work-over-time power or force-times-velocity power tools that expect different inputs.
What you can do with it
Homework and lab lift-power drills
Students and graders confirm average watts to raise a given mass through a stated height in a fixed time, with clear rejection when time is zero or a field is missing.
Hoist and winch sizing sketches
Quick structured numbers for ideal lift power from known mass, height, and duty interval without standing up a full multi-body dynamics stack.
FAQ
Which formula does the power to lift calculator use?
Average lift power: P = m·g·h / t. Work in joules is mass times gravity times height; power in watts is that work divided by time.
What happens if time is zero?
Zero time is not allowed because power would require division by zero; those calls are not charged.
Is the power to lift calculator free?
The browser tool runs free on your device.
What gravity value is used if I leave it out?
Standard Earth gravity of 9.80665 m/s². You can enter another positive value for a different location or another world; zero or negative gravity is rejected.
Does the result include motor efficiency or friction?
No. It is the ideal average power to raise the load, with no friction, no motor efficiency and no varying speed, so a real motor must be sized with its own losses on top.
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
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/mech/power-to-lift \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"mass":50,"height":10,"time":5}'const res = await fetch("https://api.kit.forhosting.com/mech/power-to-lift", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"mass": 50,
"height": 10,
"time": 5
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/mech/power-to-lift",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"mass": 50,
"height": 10,
"time": 5
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/mech/power-to-lift", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"mass":50,"height":10,"time":5}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"mass":50,"height":10,"time":5}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/mech/power-to-lift", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"mass": 50,
"height": 10,
"time": 5
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "mech.power_to_lift",
"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
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. |
Technical notes
This capability takes finite non-negative mass, finite height, strictly positive time, and optional gravity (default standard Earth g of 9.80665 m/s²), multiplies mass by g by height to form work in joules, divides by time to form power in watts, and returns structured JSON with mass, height, g, time, work_joules, power_watts, formula, and method. Zero time, negative time, negative mass, non-positive g, missing fields, and non-finite values fail with invalid_input before any result is returned.
What power to lift means and which quantities you need to send
Delivering mass, height, g, time, work_joules, power_watts, formula, and method as JSON makes the result easy to paste into notes, diff in automated tests, or reuse across languages without reimplementing the arithmetic.
How this calculator validates input and applies P = mgh / t
Numeric strings that parse to finite numbers are accepted so forms and CSV-style pipelines can pass values without an extra cast. Mass must be non-negative; negative mass is rejected. Gravity must be strictly positive. Time must be strictly positive; zero duration is rejected with a clear message because power is undefined when you divide by zero in this average-power model, and negative time is likewise refused. Height may be zero (zero work and zero power) or negative if you intentionally treat downward displacement as signed work under your own convention—the product m g h follows the arithmetic sign. There is no friction loss, no motor efficiency, no variable speed profile, and no unit auto-conversion; this is ideal average lift power from the known quantities. Send a JSON body with mass, height, and time. All three fields are required and must be finite: missing any field, empty strings, non-numeric text, NaN, and Infinity all fail immediately with invalid_input before any result is returned, and failed validation is not charged. Aliases are recognized for convenience: mass also accepts m, M, and load; height also accepts h, H, lift, and elevation; time also accepts t, duration, and time_taken. Gravity g is optional; when omitted the calculator uses standard gravity 9.80665 m/s², and aliases gravity, gravity_accel, gravitational_acceleration, and accel_g are accepted when you need a local or planetary value. After validation, work_joules is mass times g times height and power_watts is that work divided by time. Results are rounded to a stable decimal precision so the same input always yields the same JSON across JavaScript engines. The same pure function powers the free in-browser tool and the API path.
Practical use, limits, pricing, and delivery channels
Use the browser tool when you want an immediate watts check while grading homework, verifying a lab lift-time measurement, sizing a winch or hoist from known mass height and duty time, or comparing elevator duty cycles on a shared power basis. There is no language model, no external physics service, and no randomness, so the capacity is safe to pin in continuous-integration checks and reproducible lesson materials. Remember that real machines need extra power for friction, acceleration, and efficiency; this tool reports the ideal gravitational average only. Each successful request is one billable item at $0.002; failed validation does not consume balance. Choose units consistently—if mass is in kilograms, g in m/s², height in metres, and time in seconds, power_watts is true SI watts and work_joules is true joules. Results are fully deterministic: the same mass, height, g, and time always yield the same work_joules and the same power_watts. Wire the endpoint into mechanics drills, contest answer checkers, hoist-sizing worksheets, or preprocessing steps where you already prefer explicit domain errors—such as rejecting zero time—over opaque black-box widgets that cannot explain why a bad input was refused.
Integration use cases
Deterministic fixtures for physics tests
Pipelines that seed unit tests or interactive energy demos can call a pure P=mgh/t oracle instead of reimplementing lift power in every language.
Technical questions
How do I compute power to lift a load with this API?
Send a JSON body with mass, height, and time (optional g). The response returns mass, height, g, time, work_joules, power_watts, formula, and method.
What gravity value is used if I omit g?
Standard gravity 9.80665 m/s². Pass g (or an alias) for a local, planetary, or textbook value such as 9.8 or 10.