Is my input uploaded?

No. The website version runs locally. Input is sent only when you intentionally use the authenticated API.

Does this use a paid third-party API?

No. The result is calculated from local logic or a bundled reference dataset.

Should I independently verify the output?

Yes. Heuristic, security, legal and reference results should be checked against the authoritative source before important use.

Date & Time Calculators

Daylight Duration Calculator

Estimate daylight hours from latitude and date using solar declination, including polar day and night.

Free foreverRuns in your browserNo sign-up

LatitudeDate

Result

Enter your values and select calculate daylight.

About the Daylight Duration Calculator

Daylight Duration Calculator is a deterministic browser utility. Estimate daylight hours from latitude and date using solar declination, including polar day and night.

Processing happens locally in the website tool. The matching authenticated API endpoint uses the same shared implementation for consistent results.

Key features

Private browser-side processing
Structured copy-ready output
Shared website and API behavior
No paid external service

How to use

1Enter the requested value or document.
2Select any available options.
3Run the tool and review the structured result and stated limitations.

Examples

Daylight Duration Calculator example

The interactive tool includes an editable representative input.

Frequently asked questions

Is my input uploaded?: No. The website version runs locally. Input is sent only when you intentionally use the authenticated API.
Does this use a paid third-party API?: No. The result is calculated from local logic or a bundled reference dataset.
Should I independently verify the output?: Yes. Heuristic, security, legal and reference results should be checked against the authoritative source before important use.