A perpetual monthly calendar with ISO week numbers and lunar phases. Navigate any month or year — free, no login, no ads.
A perpetual month calendar with ISO week numbers and lunar phase — the long measure beside the short.
An online calendar is a digital tool for viewing, navigating, and planning dates across months and years. Unlike a paper calendar, a digital calendar lets you instantly jump to any month in the past or future, view ISO week numbers, and track lunar phases. The ONLINETIMER.TOOLS perpetual calendar provides all of this in a clean, fast, ad-free interface that works in any browser with no registration required.
A perpetual calendar is designed to display any month in any year, past or future, without needing to be replaced. Our calendar lets you navigate forward and backward through months and jump directly to any year. Each month view shows the full grid of days with the correct day-of-week alignment, highlights the current date, and displays ISO week numbers alongside each week. ISO week numbers are widely used in business and logistics for scheduling and project planning.
The calendar includes lunar phase indicators, showing the current moon phase for each date. The lunar cycle — from new moon to full moon and back — takes approximately 29.5 days, and tracking moon phases is useful for astronomy enthusiasts, photographers planning moonlit shoots, gardeners who follow lunar planting calendars, and anyone interested in natural cycles. Our calendar displays the four primary phases — new moon, first quarter, full moon, and last quarter — along with intermediate phases.
The ONLINETIMER.TOOLS calendar is completely free and requires no account. It loads instantly, works offline once loaded, and displays no advertisements. The interface is clean and minimalist, with clear typography and intuitive navigation controls. You can check any date in history or plan events years in advance. ISO week numbers make it easy to coordinate with international business schedules, and lunar phase tracking adds a natural dimension to your date planning. All data stays in your browser — nothing is uploaded or tracked.