English

• U.S. calendar — 2026 and 2027
• 2026 calendar with federal holidays — U.S.
• 2027 calendar with federal holidays — U.S.
• Days until calculator — countdown to a date (D-day, D−, D+)
• Suneung countdown: how many days until the 2027 academic year CSAT (South Korea)?
• Sobriety Calculator — Days and Milestone Dates
• Business days calculator: days between dates, add or subtract days
• How old am I calculator — age by date of birth
• Day of year calculator — date and day number
• Unix timestamp converter — seconds and ms
• Due date of pregnancy calculator (EDD)
• Calculator of weeks of pregnancy — weekly dates
• Period calculator — estimated dates and calendar
• Cattle Gestation Calculator — Estimated Dates and General Planning Range
• Japanese era & age chart: Western year, era year (和暦) and age
• Time calculator: hours between two times, add or subtract time
• Time calculator with lunch — weekly time card

Site operator and contact

Operated by: Dan Kim

contact@semku.com

We accept reports of errors in calculation rules, results, sources and notation, as well as reports concerning rights.

To request a correction, send the page address, the problem you found, the expected result and supporting evidence. Do not send financial information or other sensitive information.

Privacy on this page

This page lists tools. The tool list has no input fields and performs no calculations. This page does not save anything in browser storage.

To understand how the page is used and to improve the service, this page sends semku’s own usage statistics and automatic error reports. They go only to the dedicated endpoint under semku.com/api/telemetry/v1/. They are not used for advertising or third-party tracking.

The usage statistics include stages of use (such as starting an operation or requesting a copy), the times they occur and fixed identifiers that distinguish the page and feature. They do not include lists of tools or links you have opened from this page. Inputs are not sent as hashes or as size categories either. The full URL and search terms are not sent.

Operations and sessions are distinguished by randomly generated identifiers. In the browser, these identifiers exist only in temporary memory and are not written to cookies or browser storage. No identification based on cookies or combined device characteristics is used.

Error reports contain the error type, code and time, and, where available, a registered program-source identifier with line and column numbers. The error message text and stack traces are not sent. Usage statistics and error reports also carry the site identifier, the deployment version and a random record identifier. For access records such as IP addresses, browser signals (User-Agent Client Hints), region and language, see the paragraph below.

The feedback form sends the rating you chose and the text you typed in the free-text field when you press the send button. The form also sends a random ID that distinguishes the submission, along with the page, site, deployment version and type of request. There are no fields for your name, email address or phone number, and lists of tools or links you have opened from this page are not attached automatically. Before sending your text, the widget removes leading and trailing whitespace and, if you selected a rating, adds [+1] or [-1] at the start; it makes no other changes to your text. After receipt, the collector standardizes line endings and removes leading and trailing whitespace. Please do not enter personal data, passwords, authentication keys or payment details.

To improve the service, we record the country and state/province-level region at the time of your visit (an estimate based on the connecting network), which site you came from including the page path, and one display-language setting announced by your browser (for example, en-US). Location is kept to country and region only; no city or precise position is recorded. When you use the service, connection records, including your IP address, are automatically generated and retained to maintain service security and identify abnormal access. Cloudflare is the data processor for this site. Collection of this item is enabled only after this notice is published; we do not collect it retrospectively for use before collection is enabled. Query strings such as search terms are not recorded, and neither is the full list of preferred languages or the raw request headers. Collection of this information is currently disabled and will only be enabled after this notice is published. If we enable collection, we will collect and use signals your browser reports about its type and version, along with an indication of whether automation tools are being used, to identify bots. These browser signals are estimates and do not conclusively identify your browser's type or version or whether automation tools are being used. We do not collect it retrospectively for use before collection is enabled. The raw User-Agent request header is not recorded. These records are per visit only and use no identifier that links one visit to another. Recording starts only with visits after this notice is published and is not applied retroactively to earlier visits. The region and the referring site have been recorded since 2026-09-20; the display language since 2026-09-24. Browser signals are not recorded yet.

Separately, when you visit the site, the hosting provider records your IP address, the time of the request and user-agent information about your browser and device in Cloudflare Pages’ standard access logs.

For details, see the privacy policy.