Skip to content
Lizely

Days Since Counter

Save a named past start date and private Gregorian calendar-day snapshots instead of manually incrementing a number.

Privacy: your files never leave your device. All processing happens locally in your browser.

How to use

  1. 1.Enter a milestone name, choose a current or earlier YYYY-MM-DD start date, and save it.
  2. 2.Read the Gregorian calendar-day result and use Save today's snapshot whenever you want a dated local record.
  3. 3.Keep the start date unchanged while history exists, or clear local history before beginning a different milestone; export PNG or CSV when needed.

About Days Since Counter

Days Since Counter answers a calendar question rather than acting like a manual increment button. Give a milestone a short name, choose a past or current start date, and the page shows the number of whole Gregorian calendar days since that date on this device's current local day. You can save a snapshot for the date you are viewing and later export the local history as PNG or CSV. The tool is useful for neutral events such as a project kickoff, a routine change, an anniversary you are personally tracking, a maintenance interval, or a named waiting period. It does not interpret what the milestone means, create a countdown for a future event, send reminders, or claim that a date has legal, financial, medical, or contractual significance.

Calendar days need a precise rule. The date field accepts a complete YYYY-MM-DD value from 1900 through 9999. The tool validates the month and day before calculating, including the Gregorian leap-year rule: a year divisible by four is a leap year except century years unless they are divisible by 400. It then converts numeric components to UTC midnight values and subtracts complete days. Using UTC for the calculation avoids a local daylight-saving transition turning a calendar gap into 23 or 25 hours. The display is still attached to the device-local calendar day used for a saved snapshot. This distinction means a start date such as 2024-02-28 correctly reports two days on 2024-03-01, while the non-leap-year 2023-02-28 to 2023-03-01 gap reports one day.

Only a current or earlier start date is accepted. A future value is rejected instead of silently changing this product into a days-until timer. Saving a start date creates the first snapshot for today. You can use Save today's snapshot on a later visit to keep another dated result. A saved history belongs to one start date; to avoid rewriting the meaning of old entries, the tool asks you to clear local history before replacing a start date that already has snapshots. A snapshot can be zero when the milestone starts today, which is a real calendar result rather than an empty or missing count. The history list keeps those zero-day snapshots visible.

Export CSV creates a simple file with Snapshot date, Start date, and Days since columns. That gives a spreadsheet or archive enough context to interpret each saved value without relying on a browser-only label. Export PNG creates a natural 1080 by 1350 summary with a total for the active local day and recent snapshots. The image does not include a web address or your custom milestone name, which limits the amount of personal context in a shareable file. The exports are created directly in the browser through native canvas and Blob APIs. There is no account, server-side date service, upload queue, or remote calculation involved in the tool.

Your milestone name, start date, and snapshots are private local browser data. They are not sent to Lizely, synchronized across devices, or joined to a profile. Clearing this site's browser data removes the record, and a second browser begins with an empty counter. If browser storage is unavailable, the displayed calculation still works and the page tells you that it cannot retain snapshots. Use this tool when a named past date and calendar-day difference are the real task. Use Online Stopwatch for an elapsed live timer, or Online Tally Counter for manual repeated events. Enter a valid start date, read the explicit calendar-day result, save a snapshot when it is useful, and export only when you need a file outside this browser.

Methodology & sources

The tool validates a four-digit Gregorian date from 1900 through 9999, including month length and the divisible-by-4/100/400 leap rule. It calculates Date.UTC(year, month - 1, day) / 86400000 and subtracts those integer day numbers, avoiding local DST-hour differences. Snapshots are stored only under counter:days-since-counter and include zero-day results.

Frequently asked questions

Does this count calendar days or 24-hour periods?
It counts Gregorian calendar-day differences using validated date components at UTC midnight, not a local daylight-saving-sensitive elapsed duration.
Can I set a future start date?
No. This tool is for days since a past or current start date; it does not silently become a countdown.
Why must I clear history before changing the start date?
Saved snapshots have meaning only with their original start date, so clearing prevents a new date from rewriting old history.

Related tools

Device & Productivity guides

View all