Robustness

Don't pick a model. Run all of them.

Every tool that dates the crucifixion picks one reconstruction and reports the dates it produces. But the reconstruction involves at least four choices nobody can settle, and each one moves the answer. So rather than choose, this page runs the whole space and counts how often each year survives.

Read this before the numbers. What follows is a sensitivity analysis, not a probability. A year scoring 86% does not mean there is an 86% chance the crucifixion happened then. It means: across the defensible ways of reconstructing the Hebrew calendar, 86% of them put Nisan 14 on a Friday that year. It measures how much the answer depends on assumptions — nothing more. Treating it as a historical probability would be exactly the false precision this site exists to refuse.

What gets varied

The visibility criterion

A month begins when the crescent is first seen. Three ways to model that: a flat moon-age cutoff, Yallop's q (1997), and Odeh's V (2004). The latter two use real crescent width and altitude geometry; the first is the crude proxy most popular accounts amount to.

The moon-age threshold

If you use the crude proxy, how old must the moon be at sunset — 20 hours? 28? Every value in that range has been defended, and the choice moves dates by a full day.

Which lunation is Nisan

Full moon after the equinox, new moon after the equinox, or Stern's finding that first-century practice ran late and Passover always followed the equinox. These can differ by an entire month.

ΔT

The dynamical-to-universal time correction is about 2.86 hours at this epoch, extrapolated from sparse eclipse records. We vary it by ±10 minutes, which is conservative.

The sweep

Showing the default sweep, computed when this page was built. Change anything above and it recomputes in your browser — nothing is sent anywhere.

AD 2785.7%
AD 3057.1%
AD 3328.6%
AD 3415.9%
YearModels survivingShareDate(s) produced
AD 2754 / 6385.7%11/4 (54)
AD 3036 / 6357.1%7/4 (36)
AD 3318 / 6328.6%3/4 (18)
AD 3410 / 6315.9%23/4 (10)

How to read this

Run it on the defaults and the ranking is not the one you would expect from popular accounts. The year that survives the most models is AD 27. AD 30 is next. AD 33 — the date most often presented as established — is the least robust of the three, surviving only the narrower end of the parameter space.

This is not an argument that the crucifixion happened in AD 27. It is a demonstration of something the literature already concedes but tools rarely show: the calendar alone does not single out a year. The narrowing to AD 30 and AD 33 is done with non-calendrical evidence — the length of the ministry, John the Baptist beginning in the fifteenth year of Tiberius, the tenure of Pilate. Those are historical arguments, and no ephemeris adjudicates them.

What the sweep does establish is narrower and sturdier: any claim that the astronomy by itself pins the date to a single year is not supported by the astronomy.

The limits of this page. The space swept here is the space this software implements — three criteria, three Nisan rules, one range of ΔT error. It is not every model a scholar might defend, and the weights are uniform because there is no principled way to weight them. A different space would give different percentages. The robust finding is the spread, not the decimals.

How each of these models is computed →