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Everyday tool

Calendar

Browse a local month calendar with today highlighted. Free online tool — no sign-up. Clear formulas and worked examples. Runs locally in your browser.

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How to use

1

Browse the month

Use Prev / Next to change months; Today jumps back to the current month.

2

Find today

The current day is highlighted in the grid.

3

Use locally

The calendar runs on your device—no account or sync required.

Calendar specification

Version 2.0.0 · Runtime tested · Local-first

App status
  • Runtime tested Passed
  • Local-only Verified
  • Server data transfer None
  • App version 2.0.0

Local-first runtime specification · Review policy

Definition
A month calendar lays out the days of a chosen month in a seven-column week grid.
What it does
Day cells for a viewed year-month, with today highlighted when in view.
Inputs
  • Prev / Next month
  • Today (jump to current month)
Outputs
  • 7×N day grid
  • Month and year label in status
Rules
firstDow = weekday of day 1; days = last day of month
Assumptions
  • Uses the device local timezone Date.
  • Week starts on Sunday.
Units
  • Calendar days
Limitations
  • Months with fewer than 31 days show fewer cells.
  • Today highlight only when the viewed month is the current month.
Example
July 2026 grid with the 28th highlighted if today is July 28, 2026
Validation cases
  • Next from January → February of same year
  • Today → Current local month
Sources
  • ECMAScript Date month arithmetic
App version
2.0.0

About this tool

Details and tips for this tool.

The Calendar shows a clean month grid with today highlighted. Switch months with Prev and Next, or press Today to jump back. The month grid sits in the main panel so it is usable on a phone’s first screen.

→ Today's Date › → Current Time › → To-do List › → Online Notepad ›

Frequently asked questions

Key distinctions behind the tool.

Does this calendar sync events?

No. It is a month grid for browsing dates on your device—no cloud calendar sync.

How do I jump to today?

Press Today to return to the current month with today highlighted.

Which week starts on Sunday?

The grid uses Sunday-first columns (Su–Sa).

Is my data uploaded?

No. The calendar is generated locally from your device date.