Raid Lockout Calculator
See how many weekly lockouts you need for a 50% or 90% chance of at least one drop.
Plan raid farming around weekly clears, not raw attempts. Enter your per-clear drop chance and how many clears you can do each week.
Your details
Use the chance for one full clear, in percent.
How many eligible clears you can do each weekly reset.
Result
Rounded up to the next whole week.
- Weeks to 90% chanceRounded up to the next whole week.
- 22
- Clears needed for 50%Total clears across all weeks.
- 7
- Clears needed for 90%Total clears across all weeks.
- 22
About this tool
Raid Lockout Calculator: Weeks to a DropLearn how weekly lockouts turn drop chance into real odds. This guide shows the simple math behind 50% and 90% drop targets.
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Raid Lockout Drop PlannerTrack how many weekly clears you need to reach 50% and 90% odds of at least one drop.
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Raid Lockout Calculator infographicThe key numbers as one image — free to save, share, or embed on your own site with credit.
How this is calculated
This uses the standard at-least-one probability: 1 - (1 - p)^n, where p is the drop chance per clear and n is total clears. To convert a weekly clear limit into time, it finds the total clears needed for 50% and 90% confidence, then divides by clears per week. It assumes each clear is independent and that the drop chance stays the same every week. It does not model pity, bad-luck protection, shared loot tables, bonus rolls, or multiple items dropping at once.
Common questions
- Why does it use weekly lockouts instead of raw attempts?
- Because raid farming is usually limited by reset timers. This shows the time cost in weeks, which is what players actually plan around.
- Does a 10% drop chance mean I should expect it in 10 clears?
- Not exactly. Ten clears gives you about a 65.1% chance of at least one drop, while 90% confidence takes much longer.
- What if my raid has bonus rolls or pity protection?
- Those change the real odds. This calculator assumes a fixed per-clear chance and independent clears only.
Take it further with AI
Copy this into ChatGPT or Claude with your own numbers filled in. It hands over the figures this calculator worked out, so the answer is built on real arithmetic instead of a guess.
I used the Raid Lockout Calculator at https://www.bfcbrilliance.com/tools/raid-lockout-calculator.
What I entered:
- Drop chance per clear (%): ___
- Clears allowed per week (clears): ___
What it calculated:
- Weeks to 50% chance: ___
- Weeks to 90% chance: ___
- Clears needed for 50%: ___
- Clears needed for 90%: ___
Use those figures as given — they are already worked out, so please don't recalculate or estimate your own. Help me turn them into a plan: what to buy or do, in what order, roughly what it should cost, and the mistakes people most often make with this job.Last updated
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Part of a bigger job
How to Think About Drop RatesWhy a 1-in-100 drop doesn't arrive in 100 tries, what 'average pulls' hides, and the grind milestone that's exactly half the total.
Walks through all 5 drop rates & grinding tools in order.