Shabbat Candle Lighting & Havdalah Time Calculator
What this Shabbat calculator estimates for candle lighting and havdalah
This Shabbat calculator turns a Friday date, a latitude and longitude, and a UTC offset into two practical observance times: candle lighting before Shabbat begins on Friday evening, and havdalah after Shabbat ends on Saturday night. It is meant for quick planning when you know the place and date but want a clock time you can actually use, not a replacement for a community calendar or rabbinic schedule.
- Candle lighting (Friday): commonly set to a fixed number of minutes before local sunset in many communities, often 18 minutes, though some schedules use a different margin or publish a slightly earlier time.
- Havdalah (Saturday night): commonly set to a fixed number of minutes after local sunset, often 42 minutes as a practical approximation of nightfall, though communities that use other definitions of tzeit may arrive at a different time.
The calculator anchors both outputs to an estimated local sunset and then applies the minute buffers built into this page. If you are comparing a synagogue bulletin, travel plan, or holiday meal schedule, treat the result as a location-specific baseline and cross-check it against the custom your community follows.
Inputs you’ll need for a Shabbat candle-lighting and havdalah estimate
For this Shabbat calculator, the date tells it which Friday and Saturday pair to evaluate, while the location inputs determine how the sunset estimate shifts from place to place. Because sunset changes with geography and season, even a small longitude or UTC-offset error can move the answer enough to matter.
- Date: choose the Friday you care about. Havdalah is computed for the following day, Saturday, so a single date covers the whole Shabbat window.
- Latitude: valid range −90 to +90. North is positive; south is negative. This matters more as you move farther from the equator because the daylight arc changes more quickly.
- Longitude: valid range −180 to +180. East is positive; west is negative. The sign determines whether the local sunset is shifted earlier or later.
- Time zone offset from UTC (hours): for example, UTC−5 or UTC+2. If daylight saving time is in effect on your date, use the offset that matches the clock time in force that day.
Tip: If your Shabbat times look off by about one hour, the most common reason is a daylight-saving mismatch in the UTC offset rather than a problem with the latitude or longitude. If the result looks far more wrong than that, re-check the longitude sign and make sure you entered the Friday you intended.
Core formulas behind this Shabbat sunset estimate
The sunset step that drives both Shabbat outputs uses a standard solar-position approximation: given your latitude, the selected date, and the Sun's declination for that day, the calculator solves for the hour angle where the Sun reaches the chosen zenith distance.
Once the sunset estimate is available, the Shabbat times are simple offsets from it. The calculator subtracts a fixed amount for Friday candle lighting and adds a fixed amount for Saturday havdalah, which keeps the page focused on the timing convention rather than on extra astronomy settings.
- Candle lighting = sunset time − 18 minutes (common default used here)
- Havdalah = sunset time + 42 minutes (common default used here)
How to interpret the Shabbat candle lighting and havdalah results
These Shabbat candle lighting and havdalah results are best read as planning guidance. A sunset-based calculator gives you a practical clock time, but it cannot know every local custom, so the output should be compared with the practice your community actually follows.
- If the page shows a Friday candle lighting time, treat it as the latest target time to have candles lit before Shabbat begins. Many people aim a few minutes earlier so there is no rush as sunset approaches, and some communities publish a slightly different safety margin.
- If the page shows a Saturday havdalah time, treat it as an estimate of when Shabbat has ended under a "minutes after sunset" convention. Communities vary in how they define nightfall, so this may differ from synagogue schedules or from calendars that use a different tzeit rule.
- If you see unusual outputs, such as very early or very late times, double-check the longitude sign (east versus west) and the UTC offset before assuming the calculator is wrong. A small input mistake can push the result by much more than the built-in candle-lighting or havdalah buffer.
Worked example: a Jerusalem-area Shabbat estimate
Scenario: Suppose you enter a Friday date for a Jerusalem-area location and provide the UTC offset that applies on that date. The calculator estimates Friday sunset for that place, moves candle lighting 18 minutes earlier, and then estimates Saturday sunset and moves havdalah 42 minutes later.
- The calculator estimates Friday sunset for that location and date.
- It places candle lighting 18 minutes before that sunset.
- It estimates Saturday sunset and places havdalah 42 minutes after it.
If your community follows a different candle-lighting buffer or a different definition of nightfall, use the calculator as a comparison point and then follow the schedule your community publishes. The point of the example is to show how the sunset anchor and the two offsets work together, not to override local practice.
Limitations and assumptions for Shabbat timing
These limitations matter because this page is a sunset-based Shabbat calculator, not a formal halachic decision tool. The built-in assumptions are meant to be clear, so you can see where the calculator is following a convention and where your community may differ.
- Not halachic psak: This is an estimator. Shabbat times depend on definitions such as sunset versus other twilight markers, plus local custom and seasonal practice.
- Offsets are conventions: The 18-minute candle-lighting buffer and 42-minute havdalah buffer are common defaults, but they are not universal and should be compared with the schedule your community actually follows.
- DST handling: You provide the UTC offset. The calculator does not automatically know whether daylight saving time applies to your date or location, so that choice is on you.
- Elevation not modeled: Local horizon height and observer elevation can shift apparent sunset by a few minutes, especially in areas with mountains or tall buildings.
- Extreme latitudes: Near the Arctic or Antarctic circles, standard sunset formulas and "minutes after sunset" conventions may become unstable or stop applying in some seasons.
- Atmospheric variability: Refraction varies with pressure and temperature; standard constants approximate average conditions rather than a specific weather report.
Best practice: When in doubt, confirm the result with your local synagogue schedule or a trusted Jewish calendar for your community, especially when travel, holiday meals, or a community observance depends on the time.
How this Shabbat sunset estimate is computed (high-level)
Sunset is the anchor for both Shabbat outputs on this page, so the calculator first estimates sunset for Friday and Saturday separately.
- Convert the selected date into a day-of-year value used by standard solar-position approximations.
- Estimate the Sun’s apparent position (declination and right ascension) for that day.
- Compute the hour angle at sunset for the given latitude using a standard "sunset zenith" constant that approximates refraction and the Sun’s radius (often near 90.833°).
- Convert that to a civil clock time, then shift from UTC using your entered offset.
- Apply the Shabbat-style minute offsets: candle lighting = sunset − 18 minutes, havdalah = sunset + 42 minutes.
Common Shabbat conventions compared
The table below shows the defaults this calculator uses and the assumptions those defaults stand in for. It is meant to separate the built-in conventions from the practices that may differ by community, city, or season. Communities may choose different minute buffers or different ways of defining nightfall, so the final times can vary from place to place.
| Item | Common rule-of-thumb | What it’s approximating | Why it may differ locally |
|---|---|---|---|
| Candle lighting | 18 minutes before sunset | Practical "before sunset" margin | City or community minhag; seasonal schedules; local rabbinic guidance |
| Havdalah | 42 minutes after sunset | Rule-of-thumb for nightfall | Different definitions of tzeit; latitude and season; community practice |
| Sunset itself | Calculated (zenith ≈ 90.833°) | Accounts for refraction and the Sun’s radius | Elevation, atmospheric conditions, and algorithm choice can shift results slightly |
If a printed calendar disagrees by a few minutes, the difference usually comes from the custom being used rather than from the idea of sunset itself.
Method note for this Shabbat calculator
The solar position and sunset estimate follow widely used civil, NOAA-style approximation steps: mean anomaly, ecliptic longitude, declination, hour angle, and clock-time conversion. Those steps make the page fast enough for everyday use while still producing a location-specific answer. Halachic timekeeping may use different definitions and should always be checked against local practice.