CS2 Case Odds Calculator
Every CS2 case opening is a gamble. Use this calculator to understand exactly what your odds are before spending money on keys — and decide whether the expected return justifies the cost.
How Many Cases Will You Open?
Expected Drops from 100 Cases
| Rarity | Expected Drops | Probability of At Least 1 |
|---|
Official CS2 Case Drop Rates
Valve disclosed the exact rarity probabilities for CS2 cases. These odds are identical across every standard weapon case:
| Rarity Tier | Drop Chance | Odds Ratio |
|---|---|---|
| Mil-Spec (Blue) | 79.92% | ~4 in 5 |
| Restricted (Purple) | 15.98% | ~1 in 6.3 |
| Classified (Pink) | 3.20% | ~1 in 31.3 |
| Covert (Red) | 0.64% | ~1 in 156.3 |
| Rare Special Item (Gold) | 0.26% | ~1 in 384.6 |
The Mathematics Behind Case Openings
CS2 case openings follow a binomial probability distribution. Each case is an independent event — opening 384 cases doesn't guarantee a knife, just as flipping heads 10 times in a row doesn't make the next flip more likely to be tails. The probability of getting at least one knife in N cases is: P = 1 - (1 - 0.0026)^N.
This means after 100 cases, your knife probability is about 22.9%. After 500 cases it rises to 72.7%, and after 1,000 cases you're at 92.6%. Even after 2,000 cases, there's still a 0.55% chance you haven't seen a single knife — that's the nature of independent random events.
Expected Value and ROI
The expected return from opening a standard CS2 case averages around $0.80–$1.50 per case depending on the specific case and current market prices. Since each opening costs approximately $2.50 (case + key), the average player loses about $1.00–$1.70 per case opened. Over 100 cases, you should expect to lose roughly $100–$170.
However, this average is heavily skewed by rare outcomes. Most of your returns come from the small chance of hitting a high-value knife or glove. A single Karambit Fade Factory New can be worth $1,000+, which would offset hundreds of losing cases. This variance is what makes case opening feel "worth it" despite the negative expected value.
StatTrak and Wear Probabilities
About 10% of case drops come with StatTrak technology. Combined with the five wear conditions (Factory New, Minimal Wear, Field-Tested, Well-Worn, Battle-Scarred), this creates tiered sub-probabilities. A specific StatTrak Factory New Covert skin has roughly a 0.0064% chance per case — about 1 in 15,600 openings.
Frequently Asked Questions
- What are the odds of getting a knife from a CS2 case?
- The chance of unboxing a knife or glove (Rare Special Item) from any CS2 case is approximately 0.26%, or roughly 1 in 385 cases. This means you would statistically need to open 385 cases to expect one knife drop.
- Are CS2 case odds the same for every case?
- Yes, all standard CS2 weapon cases share the same rarity drop rates. The odds of getting a Mil-Spec, Restricted, Classified, Covert, or Rare Special Item are consistent regardless of which case you open.
- Is opening CS2 cases profitable?
- On average, no. The expected value of opening a standard case is typically $0.80–$1.50, while each case costs $2.49 plus a key. However, rare knife or glove drops can be worth hundreds or thousands of dollars, which is what makes it exciting.
- How many cases do I need to open for a guaranteed knife?
- There is no guaranteed number — each case is an independent event. However, after opening 1,000 cases, you have roughly a 92.6% chance of having received at least one knife. After 1,500 cases, it rises to 98%.
- What is the rarest item you can get from a CS2 case?
- The rarest items are StatTrak Factory New knives or gloves from the Rare Special Items pool. The combined probability of a specific StatTrak FN knife pattern can be as low as 1 in 100,000+ cases.