Quarter start and end dates
Q1 of 2026 runs from 1 January to 31 March 2026. Pick a year and a quarter from 1 to 4 and get the exact first and last day, ready for report filters, dashboards and period-close checklists. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Year
- 2,026
- Quarter
- 1
- Quarter label
- Q1
- Months
- January–March
- Start date
- 2026-01-01
- End date
- 2026-03-31
Calendar quarters divide a Gregorian year into four fixed blocks: January through March, April through June, July through September, and October through December. Finance teams, reporting dashboards, and product analytics all need the exact first and last calendar day of a quarter when building filters, fiscal close checklists, or scheduled exports. This capability takes a year and a quarter number from one to four and returns inclusive start and end dates as stable YYYY-MM-DD strings, plus structured month and day fields for tables and forms. Quarter numbers outside one through four fail with a clear invalid input error and are not charged.
What a calendar quarter is and how to send year and quarter
A standard calendar quarter is one of four consecutive three-month ranges inside a Gregorian year. Quarter one always starts on the first of January and ends on the thirty-first of March; quarter two runs from the first of April through the thirtieth of June; quarter three from the first of July through the thirtieth of September; and quarter four from the first of October through the thirty-first of December.
Those boundaries never shift with weekdays, leap years, or locale settings, because they are fixed calendar dates rather than ISO week rules or company-specific fiscal calendars. Missing fields, non-integers, and out-of-range values raise invalid input so pipelines can fail fast without guessing. The response always echoes the normalized year and quarter so clients can log exactly what was resolved.
Use this tool when you need the public calendar definition of Q1 through Q4, not a custom fiscal year that starts in July or a 4-4-5 retail calendar.
What you can do with it
Product analytics date pickers
Dashboards prefill quarter range controls from year plus quarter number so users can jump to “this quarter” or “Q4 last year” without manual calendar math.
FAQ
What happens if the quarter is outside 1 to 4?
Only calendar quarters Q1 through Q4 are supported; values such as 0 or 5 are rejected and not charged.
Are these fiscal quarters or calendar quarters?
Calendar quarters only: Q1 is January–March, Q2 April–June, Q3 July–September, and Q4 October–December. Custom fiscal calendars are out of scope.
Is the quarter start and end dates calculator free?
The browser tool runs free on your device.
Do leap years change quarter boundaries?
No. Under the Gregorian calendar quarter table used here, every quarter starts and ends on fixed month-day pairs that do not depend on February 29.
Are the start and end dates part of the quarter?
Yes. Both dates are included, so every day from the first date through the last one belongs to the quarter. Q1 therefore contains both 1 January and 31 March.
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/date/quarter-start-end \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"year":2026,"quarter":1}'const res = await fetch("https://api.kit.forhosting.com/date/quarter-start-end", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"year": 2026,
"quarter": 1
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/date/quarter-start-end",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"year": 2026,
"quarter": 1
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/date/quarter-start-end", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"year":2026,"quarter":1}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"year":2026,"quarter":1}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/date/quarter-start-end", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"year": 2026,
"quarter": 1
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "date.quarter_start_end",
"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
The algorithm is a pure table lookup with integer validation—no network calls, no wall clock, and no host timezone—so the same input always yields the same JSON.
What a calendar quarter is and how to send year and quarter
Send the required field year as a JSON integer or an integer string between one and nine thousand nine hundred ninety-nine; aliases y and yr are accepted. Send the required field quarter as an integer from one to four; aliases q and qtr are accepted.
Reading start_date, end_date, and the structured quarter fields
Leap years do not change quarter start or end dates under this contract, because no quarter boundary falls on the twenty-ninth of February; March thirty-first, June thirtieth, September thirtieth, and December thirty-first are fixed. Year outside the published min and max fails the same way so silent overflow never invents a date. On success the response includes year, quarter, quarter_label such as Q2, a human-readable months string like April–June, and the two primary date strings start_date and end_date in YYYY-MM-DD form with zero-padded month and day. Those strings are inclusive: every day from start through end belongs to the quarter. The same bounds are also returned as integers start_month, start_day, end_month, and end_day so spreadsheet formulas and UI date pickers can bind without re-parsing ISO strings. The calendar field is always gregorian and method is always calendar_quarter so downstream code can branch without sniffing shapes. Use start_date and end_date alone for SQL BETWEEN clauses and API date filters; use the numeric month and day fields when building multi-column reports; use quarter_label when a chart legend needs a short badge. Quarter outside one to four fails with invalid_input mentioning the quarter range and is not charged.
API usage, pricing, reporting workflows, and practical limits
Call the free in-browser quarter start and end dates tool for spreadsheet checks, slide decks, and quick mental verification of reporting windows without installing a calendar library. Send a JSON body with the required integer year and the required integer quarter from one to four. Use the prepaid API when a billing pipeline, BI extract, cron job, or SaaS dashboard needs a stable contract under KIT balance at $0.002 per successful item; validation failures never consume balance after the engine rejects the request. Pair this endpoint with days-in-month or months-between tools when the next step is counting days inside the quarter or spanning multiple quarters. Authors shipping SDKs can map start_date and end_date directly into date-range controls, while mapping quarter_label into titles such as Q3 2026. This product does not convert fiscal-year offsets, ISO week-based quarters, or half-year periods—those are different search intents—so keep custom fiscal logic in your own layer and call this capacity only for standard calendar Q1 through Q4.
Integration use cases
Financial reporting windows
Controllers and FP&A tools resolve Q1–Q4 inclusive date ranges for a given year, then feed start_date and end_date into ledger filters, close checklists, and board packs.
Scheduled exports and cron jobs
Batch jobs pass a year and quarter to obtain stable ISO bounds for CSV extracts, warehouse partitions, and retention windows pinned in CI fixtures.
Technical questions
How do I get the start and end dates of a quarter?
Send JSON with year (for example 2026) and quarter from 1 to 4. The response includes start_date and end_date as YYYY-MM-DD plus structured month and day fields.