Time adder
1 hour 45 minutes 30 seconds plus 80 minutes and 90 seconds adds up to exactly 3 hours 7 minutes. Stack podcast chapters, workout intervals or meeting segments and get one clean total. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Adding several stopwatch blocks is a daily chore that a clock face cannot answer: two podcasts of one hour forty-five and fifty minutes, three workout intervals, a film plus trailers plus ads, a commute with two transfers. This time adder takes multiple durations given as hours, minutes, and seconds, adds every component, and normalizes the total so minutes and seconds sit in the usual zero-to-fifty-nine range while hours grow as far as the sum requires. It is not a clock-plus-hours tool and not a calendar date adder: there is no midnight wrap and no time zone. Negative hours, minutes, or seconds are rejected as invalid input instead of inventing a signed length no kitchen timer would display.
What adding several durations actually computes
A duration is a length of time, not a time of day. When you add one hour forty-five minutes thirty seconds to eighty minutes and ninety seconds you are stacking stopwatch blocks, not sliding a clock hand past midnight. Convert each block to a single unit — seconds — so the arithmetic cannot forget a carry: one hour is three thousand six hundred seconds, one minute is sixty seconds, and leftover seconds stay as seconds.
Sum those totals across every row, then split the grand total back into hours, minutes, and seconds with ordinary integer division. Seconds that reach sixty become an extra minute; minutes that reach sixty become an extra hour; hours are allowed to grow past twenty-four because a duration is not a clock face. That is the normalization this time adder always applies.
The same path rejects any negative hour, minute, or second instead of inventing a signed duration that no kitchen timer would display. Nothing here consults a system clock, a time zone, or a calendar: the result is a pure function of the numbers you sent. A clock-plus-hours tool answers a different search — what time is it after eight hours.
An ISO-8601 duration adder answers another — PnYnMnD strings. A general time calculator that also subtracts or converts from total seconds answers a broader query. This page is only the hours-minutes-seconds summer people type into a search box as time adder, and the contract is deliberately narrow so the answer never drifts into clock math.
Where a time adder earns its keep
Editors and podcasters add chapter lengths, trailer blocks, and mid-roll ads to publish a runtime that matches the file they will ship. Coaches and athletes add warm-up, intervals, and cool-down so a session plan shows one number instead of a column that still needs a calculator. Project managers add meeting segments and commute legs when a day is billed by the stopwatch rather than by the clock on the wall.
Teachers and exam-prep sites need a deterministic oracle that marks eighty minutes plus ninety seconds as one hour thirty-one minutes, not as a one-hour clock with leftover seconds left uncarried. Video teams add scene lengths before they cut a reel; parents add homework blocks and chore windows before they promise an evening. Pair this adder with a clock-plus-hours tool when you need a finish time of day, and with a date-plus-days tool when you need a civil date rather than a length.
What you can do with it
Sum workout or interval blocks
Add warm-up, work intervals, rest, and cool-down given as hours, minutes, and seconds to get one normalized session length.
Add video or podcast runtimes
Stack chapter lengths, trailers, and ads so the published runtime matches the file you will ship, with carry already applied.
Total commute or meeting segments
Add each leg of a trip or each block of a billed day and return a single duration instead of a column that still needs a calculator.
FAQ
How do I add several hours-minutes-seconds durations?
Send durations as an array of objects with hours, minutes, and seconds (missing parts default to 0).
What happens if a component is negative?
A duration component cannot be negative; the adder will not invent a signed length. Failed validation is not billed.
Do minutes and seconds have to be under 60?
Not on input. Eighty minutes or ninety seconds is accepted on a row. After the sum, seconds and minutes are carried so the result sits in the usual 0–59 range and hours grow as needed.
Is this the same as adding hours to a clock time?
No. This time adder stacks stopwatch lengths and returns a duration. A clock-plus-hours tool slides a time of day and reports a midnight wrap. Use the tool that matches the search you meant.
Can the total go past 24 hours?
Yes. A duration is a length of time, not a time of day, so hours keep growing as far as the sum needs and never wrap around at midnight. Only minutes and seconds are carried into the next unit.
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/life/time-adder \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"durations":[{"hours":1,"minutes":45,"seconds":30},{"hours":0,"minutes":80,"seconds":90}]}'const res = await fetch("https://api.kit.forhosting.com/life/time-adder", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"durations": [
{
"hours": 1,
"minutes": 45,
"seconds": 30
},
{
"hours": 0,
"minutes": 80,
"seconds": 90
}
]
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/life/time-adder",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"durations": [
{
"hours": 1,
"minutes": 45,
"seconds": 30
},
{
"hours": 0,
"minutes": 80,
"seconds": 90
}
]
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/life/time-adder", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"durations":[{"hours":1,"minutes":45,"seconds":30},{"hours":0,"minutes":80,"seconds":90}]}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"durations":[{"hours":1,"minutes":45,"seconds":30},{"hours":0,"minutes":80,"seconds":90}]}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/life/time-adder", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"durations": [
{
"hours": 1,
"minutes": 45,
"seconds": 30
},
{
"hours": 0,
"minutes": 80,
"seconds": 90
}
]
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "life.time_adder",
"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.
Limits
min_items | 1 |
max_items | 200 |
max_total_seconds | 1000000000000000 |
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
Successful API calls use the published $0.002 base price; failed validation is not billed.
Input contract, carry rules, and the response shape
Each object may carry hours, minutes, and seconds as finite non-negative numbers; a missing component defaults to zero so a row of only minutes is a valid stopwatch block. Minutes and seconds may exceed fifty-nine on input — eighty minutes and ninety seconds is legal — because the adder normalizes after the sum, not before. Example: one hour forty-five minutes thirty seconds plus eighty minutes and ninety seconds is eleven thousand two hundred twenty seconds, which normalizes to three hours, seven minutes, and zero seconds. POST a JSON body with one required field: durations, an array of at least one object. Aliases times, items, and list are accepted so spreadsheets and typed forms can reuse the same contract. Any negative component fails with invalid_input and a message that names the field and says it cannot be negative; those failures are not billed. An empty list, a non-array, or a row that is not an object also fail as invalid_input. On success the body includes count (how many rows were added), hours, minutes, and seconds of the normalized total, total_seconds as a single scalar, decimal_hours for spreadsheets that prefer a decimal length, hms as a zero-padded H:MM:SS string, and a short formula restating the sum-then-carry identity. Pair the response with your own display if you need days extracted from large hour counts; this endpoint returns unbounded hours after carry, not a clock of the day.
Where a time adder earns its keep
On this page the work runs entirely in your browser; through the API each successful sum costs $0.002, failed validation is not charged, and nothing is stored after the response returns.
Technical questions
What does the time adder cost?
The browser tool is free. API requests use prepaid balance at $0.002 per successful call; invalid input is not billed.