How do we determine the date to celebrate Easter?

TL;DR:

While the exact date of Easter is not specified in the Bible, we do know the crucifixion occurred around Passover time, and Jesus was resurrected three days after His death. Today, we celebrate Easter the first Sunday after the full moon following the vernal equinox.

what does the bible say?

We don’t know much about the specific time of Jesus’ crucifixion or resurrection, other than that His crucifixion happened one day before the Sabbath (John 19:31)—which some speculate was actually the Passover—and that His resurrection occurred three days after His death (1 Corinthians 15:3-4). Even if the timeframe of the crucifixion and resurrection could be determined within the week, we don't know the specific date or even year. The most that can be said is that Jesus was crucified around the Passover (the fifteenth of Nisan), sometime during Pilate's rule (AD 26-36). The date of Jesus' resurrection and the date that we celebrate Easter have only two connections: The early church held that Jesus was resurrected on a Sunday, and Passover is in the spring. The flux in the date of Easter is a perfect example of what Paul meant when he said, "One person esteems one day as better than another, while another esteems all days alike. Each one should be fully convinced in his own mind. The one who observes the day, observes it in honor of the Lord. The one who eats, eats in honor of the Lord, since he gives thanks to God" (Romans 14:5-6b). The date we celebrate Easter is less relevant than that our focus should be to honor God.

from the old testament

The Old Testament provides the foundation for determining the timing of Jesus’ death and resurrection because Easter is tied to Passover. God commanded Israel to observe Passover on the 14th day of the first month (Nisan/Abib) in the Hebrew calendar (Exodus 12:1–6, 18–19). Jesus’ crucifixion occurred during Passover, fulfilling the imagery of the sacrificial lamb (Exodus 12:21–27; see John 1:29; 19:14).
The Hebrew calendar is lunar, so Passover varies each year on the Gregorian calendar. The Old Testament establishes the rhythm of months and festivals (Leviticus 23:4–5), which informs how the early church calculated Easter.
Passover commemorated Israel’s deliverance from Egypt (Exodus 12:12–13). Easter celebrates Jesus as the ultimate Redeemer, the true Passover Lamb (1 Corinthians 5:7), so its timing follows the Old Testament festival as a theological link.

from the new testament

While the Bible tells us that Jesus was crucified the day before the Sabbath (John 19:31), some speculate that the Sabbath in question may not have been the Friday-evening to Saturday-evening weekly Sabbath, but the day of the Passover.
The Bible neither clearly identifies the day of Christ's resurrection nor instructs Christians to celebrate it. IAcknowledging Jesus' crucifixion and resurrection is commendable, and it's fine for the church to corporately to determine a date each year to do so. However, we should keep in mind Romans 14:5-6b about honoring God whether or not we celebrate such days.
In 1 Corinthians 15:3-4 Paul says: “For I delivered to you as of first importance what I also received: that Christ died for our sins in accordance with the Scriptures, that he was buried, that he was raised on the third day in accordance with the Scriptures…” We know by this verse that Jesus’ crucifixion occurred just three days after His death.

implications for today

It is impossible to pinpoint the exact date of Jesus' resurrection, but what we do know is that Jesus was crucified the day before the Sabbath (John 19:31). Today, the date on which we celebrate Easter has more to do with pagan holidays than the date of Jesus’ resurrection. Historically, as Christianity spread, the belief in the new life in Christ took over pagan spring fertility ceremonies. While cultural details, such as an association with the vernal equinox and the name "Easter," remained, the religious aspect of the celebration completely changed. Thus, Easter is celebrated on the first Sunday after the new moon following the northern hemisphere's vernal equinox. Because western churches use the Gregorian calendar and eastern churches use the Julian calendar, and because the early church took quite a while in precisely describing the method by which Easter's date would be determined, it gets very confusing. In general, however, Easter falls on a Sunday between March 22 and April 25.

understand

Scripture doesn’t specify the exact date of Easter, but it does indicate that the crucifixion occurred around Passover time, and Jesus was resurrected three days after His death.
Today, in the western church, Easter falls on the first Sunday after the full moon following the vernal equinox.
God doesn’t command Christians to celebrate Easter, but those who do should focus on glorifying God in the celebration of it.

reflect

How do you ensure that Christ is at the center of your Easter celebrations?
How does reflecting on Christ’s suffering, death, and resurrection encourage you in the faith?
In what matters that are not biblically commanded do you allow your conscience to guide you—such as holidays that are not specified in the Bible?

engage

How does understanding the connection between Passover and Jesus’ crucifixion deepen our appreciation of Easter?
In what ways can Christians celebrate Easter while keeping the focus on Christ rather than cultural or traditional practices?
How can we thoughtfully respond to questions about the timing or “pagan” associations of Easter in a way that honors God and points others to the gospel?