# Pack Pull Odds Calculator (Card Pack Probability)

Work out your chance of pulling a card, or several copies, from a number of packs, and how many packs you need for 50%, 90% or 99% confidence.

- URL: https://toolstackhub.co.uk/tools/pack-pull-odds-calculator/
- Category: Calculators
- Price: free, no sign-up
- Privacy: runs in the browser; input is not uploaded
- Last updated: 2026-10-08

## About
The Pack Pull Odds Calculator turns a card’s drop rate into plain answers: the chance you pull at least one (or at least k copies) in the packs you plan to open, the average number of packs it takes, and how many packs you need to be 50%, 75%, 90%, 95% or 99% sure. Optionally add a guarantee, such as a card being certain after a set number of packs. It works for any card game, gacha or loot box where you know the per-pack chance. The drop rate is whatever you type in, so use the figure published by the game.

## How to use
1. Enter the chance of the card you want in a single pack, as a percentage. Use the rate published by the game.
2. Enter how many packs you plan to open, and how many copies you want.
3. If the game guarantees the card after a set number of packs, enter that number. Otherwise leave it at 0.
4. Read the chance of success, the average packs needed and the packs required for 50% to 99% confidence.

## FAQ
**How do I calculate the chance of pulling a card?** The chance of getting at least one in n packs is 1 − (1 − p)^n, where p is the chance in one pack. For a 2.5% card in 30 packs that is 1 − 0.975^30 = 53.21%.

**How many packs do I need for a 90% chance?** Divide ln(0.1) by ln(1 − p). For a 2.5% card that is 91 packs. The calculator also shows 50%, 75%, 95% and 99%.

**What does the guarantee setting do?** It models a pity rule: the card is certain once you open that many packs without it. The average number of packs falls because the chain is cut short.

**Does opening more packs make the next one luckier?** Not with independent odds. Each pack has the same chance, so a long dry run does not raise the next pack’s chance, unless the game has a pity rule.

**Can I use this for gacha games and loot boxes?** Yes. Any system with a known per-draw chance works.

**Is the Pack Pull Odds Calculator (Card Pack Probability) free?** Yes, with no sign-up or limits.