Days Since Counter calculates the number of Gregorian calendar days that have passed between a past or current start date and this device's local day, then keeps the result as a dated snapshot inside the browser. Open the Days Since Counter, give the milestone a short name such as "Project kickoff" or "New routine", choose a complete YYYY-MM-DD start date that is today or earlier, and the page returns the count of whole calendar days between that start and the device-local day you are viewing. Saving the start date creates the first snapshot for today, and a snapshot control on later visits lets you keep another dated record. Snapshots are stored locally under the browser key counter:days-since-counter and are not sent to a server, so the milestone name, start date, and history stay on this device unless you export them. The page validates month length and the Gregorian leap-year pattern before returning a number, which is why a date such as 2024-02-28 correctly reads as two days on 2024-03-01 even though your calendar might feel shorter.
What the Tool Is Doing Behind the Curtain
Days Since Counter answers a calendar question rather than acting like a manual increment button. You give it a named past or current date, and it tells you how many whole Gregorian calendar days separate that date from the device-local day you are using right now. There is no timer running, no start button, and nothing to refresh between midnight rollovers — the count simply recomputes from the start date and the device's clock.
The number is computed by converting the year, month, and day you entered into a UTC midnight value using Date.UTC(year, month - 1, day), dividing that by 86,400,000 to get a whole day number, and finally subtracting the two integer day numbers for the start and the device-local day. Because the subtraction happens at UTC midnight, a local daylight-saving transition cannot turn a one-day calendar gap into 23 or 25 hours. The display is still attached to the device-local calendar day used for any saved snapshot, which is why the count changes when the device rolls over a local midnight, not at the moment a UTC clock ticks.
The tool will not interpret what your milestone means, create a countdown toward a future event, send you a reminder, or claim the date has legal, financial, medical, or contractual significance. If any of those are the real task, you need a different kind of tool or process. A neutral personal milestone — a routine change you started, a maintenance interval you are tracking, a personal anniversary, or the day a project kicked off — is the kind of question this page is built to answer.
Picking Your First Milestone and Start Date
The milestone name is the label that the snapshot list shows next to each row and the side effect inside the CSV file you might export later. Keep it short, neutral, and unambiguous on its own: "Quit smoking", "New sleep routine", "Garage service log", or "Project kickoff" all work well. Avoid putting your full name, address, or anything sensitive into the milestone field, since the name stays in the same local record as the count.
The start date field accepts a complete YYYY-MM-DD value from the year 1900 through the year 9999. You cannot enter "Feb 28" without a year, "28/02/2024" in day-first style, or any partial value. The page validates the month and the day before it calculates, including the Gregorian leap-year rule: a year divisible by four is a leap year, except for century years, which are leap only when divisible by 400. Because of how the validator works, 2000-02-29 is a valid date but 1900-02-29 is not.
Only a past or current start date is accepted. The form rejects a future value instead of silently turning the page into a days-until timer, so if you want a countdown toward a future date, the Online Countdown Timer is the more suitable choice. For your very first session, pick a milestone that started weeks or months ago so you can see a non-zero count the first time you load the page.
How to Open the Tool and Run Your First Count
- Open the Days Since Counter in your browser. The page shows an empty milestone field, an empty YYYY-MM-DD date field, and a save control.
- Type a short name for the milestone you are tracking, such as "Project kickoff" or "New routine".
- Choose a past or current start date in the YYYY-MM-DD format. For example, type 2024-02-28 if the milestone began on that day.
- Submit the form. The page validates the four-digit year, the month, the day, and the leap-year rule before showing a number.
- Read the Gregorian calendar-day result in the main display. Saving the start date automatically creates the first snapshot for the device-local day you are viewing.
- Come back on a later day and click the snapshot control again to keep another dated local record under the same start date.
Reading the Calendar-Day Result
The number on screen is a count of complete Gregorian calendar days between the start date you saved and the device-local day the page is open on. Two examples illustrate how the leap-year rule shows up in the display:
| Start date | Device-local day | Days since | Why |
|---|---|---|---|
| 2024-02-28 | 2024-03-01 | 2 | 2024 is a leap year, so February has 29 days |
| 2023-02-28 | 2023-03-01 | 1 | 2023 is not a leap year, so February has 28 days |
| 2000-02-28 | 2000-03-01 | 2 | 2000 is a century year divisible by 400, so it is a leap year |
| 1900-02-28 | 1900-03-01 | 1 | 1900 is a century year not divisible by 400, so it is not a leap year |
Worked example using the leap-year case: take start date 2024-02-28 and a device-local day of 2024-03-01. Both dates are first converted to UTC midnight, divided by 86,400,000, and rounded down to whole day numbers. The integer day number for 2024-03-01 minus the integer day number for 2024-02-28 equals 2, which matches the Gregorian calendar gap that includes the leap day 2024-02-29. The same subtraction for the non-leap 2023-02-28 to 2023-03-01 pair equals 1, because there is no February 29 in 2023.
Because the page uses UTC midnight for the subtraction, a local daylight-saving transition on the device cannot turn a one-day calendar gap into 23 or 25 hours. The display still updates when the device-local calendar day rolls over, which is how snapshots stay aligned with the day you intended to record. A fuller explanation of why UTC midnight is used rather than a local 24-hour period lives in the calendar-days versus 24-hour periods guide.
Saving Snapshots and Building a Local History
Saving the start date creates the first snapshot for today. On any later visit, the snapshot control adds another row to the history list with the current device-local date and the days-since value for that day. The history list belongs entirely to that one start date and is stored under the browser key counter:days-since-counter, so the snapshots are not synchronised across browsers, devices, or profiles.
A snapshot can legitimately read zero when the milestone starts today on the device-local calendar day. That is a real Gregorian result rather than an empty or missing count, and the history keeps those zero-day rows visible alongside the rest. If browser storage is unavailable on the device, the displayed calculation still works, but the page warns you that it cannot retain snapshots for later visits.
Your milestone name, start date, and snapshot history are private local browser data. They are not sent to Lizely, joined to a profile, or synchronised across devices, and clearing the site's browser data removes the record while a second browser begins with an empty counter.
Switching Milestones Without Rewriting Old Records
The history list belongs to one start date. If you change the start date while snapshots already exist, the old snapshots would suddenly mean something different, so the page asks you to clear the local history first rather than silently rewriting the meaning of past entries. Clearing empties the list of snapshots for the current milestone and lets you save a new start date as if you were starting fresh.
A clean pattern for a new milestone is therefore: export the previous one if you need an archive, clear the local history, change the milestone name, choose a new past or current start date, and save again. If you want a second milestone running alongside the first and you can keep them straight, an instance of Multi Counter lets you keep parallel day counts side by side rather than overwriting this history list.
Exporting a PNG or CSV When You Need a File
When you want a file outside the browser, the page lets you export either a PNG image or a CSV file. The CSV is a simple three-column file with Snapshot date, Start date, and Days since, which gives a spreadsheet or archive enough context to interpret each saved row without relying on a browser-only label. The PNG is a 1080 by 1350 summary that includes the total for the active device-local day and a list of recent snapshots.
Both exports are produced directly inside the browser through the native canvas and Blob APIs, which is why they work even when you are offline. The PNG summary does not include a web address or your custom milestone name, which keeps the file less identifying if you share it. The CSV keeps the start date and the snapshot date, so redact those columns before sharing the file if the dates are sensitive.
When Days Since Counter Is and Isn't the Right Pick
Days Since Counter is the right tool when a named past date and a calendar-day difference are the real task. Project kickoffs, routine changes, anniversaries you are personally tracking, maintenance intervals, and named waiting periods all sit cleanly inside that brief. It is the wrong tool when the question is "how long have I been doing X right now in hours and minutes" — for a live elapsed timer, use the Online Stopwatch instead. It is also the wrong tool for manually counting repeated events on a single day, where the Online Tally Counter fits better. For a fuller side-by-side, the decision guide walks through the same fits and avoid cases in more detail.
Open the page, name the milestone, choose a past or current YYYY-MM-DD start date, read the explicit calendar-day number, save a snapshot when it is useful, and export only when you need a file outside the browser.