You’ve probably heard people say, “I’m doing a 21-day Daniel Fast!” or thought, “Should I try fasting for 40 days like Jesus?” But here’s a surprising truth: most Christians choose their fasting lengths based on trends rather than biblical truth.

Believe it or not, the Bible never commands a 21-day fast, and a true 40-day fast is recorded only a few times throughout history. If you’ve been fasting based on popular traditions, you might be missing the full power of fasting God intended.

Let’s dive into what the Bible actually says about how long you should fast—and why getting this right could change everything about your spiritual breakthrough.

Is There a Biblical Command for How Long You Should Fast?

One of the most common questions people ask me about fasting is: “Pastor Ted, how long should I fast?” I understand why—you’re serious about doing it right and seeing results. But the truth is, the Bible doesn’t command one specific fasting length for everyone.

Romans 8:14 says, “For all who are led by the Spirit of God are sons of God.” That’s exactly how fasting should work—led by the Spirit, not by religious routines or trends.

Let’s break down the lengths of fasts we actually see in Scripture, from shortest to longest, so you can fast biblically and effectively.

Biblical Examples of Fasting Lengths:

1. Sunrise-to-Sunset Fast (Judges 20:26; 1 Samuel 14)

The shortest biblical fast lasts from sunrise until sunset. Israelites, King Saul’s army, and King David fasted this way when seeking God’s guidance or mourning. If you’re new to fasting, this is an excellent starting point.

2. 24-Hour Fast (Luke 18:12; 1 Samuel 7)

The Pharisees fasted twice weekly for 24 hours each time, and early Christians later adopted a similar practice to distinguish themselves from religious routines. Samuel led Israel in a one-day fast focused on repentance and seeking God’s favor.

3. Three-Day Fast (Esther 4:16; Acts 9:9)

Esther called a three-day total fast (no food or water) when the Jewish nation faced annihilation. Likewise, the Apostle Paul fasted three days after his encounter with Jesus on the road to Damascus.

4. Seven-Day Fast (1 Samuel 31:13; 2 Samuel 12:16-18)

After the death of King Saul, the men of Jabesh-Gilead mourned and fasted for seven days. Similarly, King David fasted for a week, pleading for the life of his child.

5. Fourteen-Day Fast (Acts 27:33)

Though mentioned, this particular fast wasn’t spiritually motivated. It was fear-induced by sailors caught in a storm. Paul himself didn’t participate, so this isn’t considered a biblical fasting model.

6. Twenty-One Day “Daniel Fast” (Daniel 10:3)

Often called the “Daniel Fast,” this is perhaps the most misunderstood biblical fast. Daniel didn’t abstain from all food; rather, he abstained from meat, wine, and delicacies. It was a dietary restriction, not a total fast. (I cover this extensively in my book, The Complete Guide to Biblical Fasting, which you can find linked at the end of this article.)

7. Forty-Day Fast (Exodus 34:28; 1 Kings 19:8; Luke 4:2)

Only three biblical figures experienced a forty-day fast:

• Moses: No food or water when receiving the Law—this was a supernatural fast.
• Elijah: Fasted after a miraculous angelic meal—again, supernatural.
• Jesus: Forty days with no food, but He did drink water. Jesus’ fast is the model for spiritual preparation and warfare.

A true forty-day fast, especially without water, is supernatural. Don’t attempt this casually—only as explicitly led by God and confirmed through deep prayer and wisdom.

So, How Long Should YOU Fast?

The question isn’t “How long should I fast?” but rather, “What is God leading me to do?”

I encourage new fasters to start with shorter, achievable fasts—sunrise-to-sunset or a full day—then build your spiritual muscles from there. Your goal is not duration; it’s spiritual effectiveness and obedience.

Fasting should always be accompanied by intentional prayer, Bible study, and a heart genuinely seeking God’s presence.

Ready to Fast the Right Way?

To make it easy for you, I’ve put together a FREE Fasting Starter Kit. It walks you step-by-step through biblical fasting, providing practical tips and scripture-backed guidance.

If you’re ready to deepen your understanding even further, pick up my book, A Complete Guide to Biblical Fasting, where I provide detailed teaching on every type of fast and answer your deepest questions about fasting.

Both resources are available right now—grab them today and begin experiencing the life-changing power of biblical fasting!

Let today be the day you begin your powerful journey of fasting, guided not by trends or traditions but by biblical truth and spiritual hunger.