CS2 Expected Items Calculator
Calculate exactly how many items you can expect to receive at each rarity tier when opening CS2 cases. This tool provides detailed breakdowns including StatTrak predictions and realistic variance ranges to help you set proper expectations.
Expected Item Breakdown
See what you should statistically expect from your case openings
How many cases you plan to open or have opened
Expected Distribution Visualization
Variance Ranges (95% Confidence)
Due to randomness, your actual results will vary. These ranges show what 95% of players would experience.
| Rarity | Expected | Low (Unlucky) | High (Lucky) |
|---|
Understanding Expected Item Counts
When you open CS2 cases, each opening is an independent random event governed by fixed probabilities. Valve has disclosed these official drop rates, making it possible to calculate statistically how many items of each rarity you should expect to receive over any number of cases.
According to Valve's official CS2 transparency disclosures, all cases share the same underlying probability distribution. This calculator uses those official rates to give you precise expectations.
Official CS2 Case Drop Rates
These probabilities are consistent across all CS2 weapon cases:
| Rarity Tier | Drop Chance | 1 in X | StatTrak Chance |
|---|---|---|---|
| Mil-Spec (Blue) | 79.92% | 1 in 1.25 | 7.99% |
| Restricted (Purple) | 15.98% | 1 in 6.26 | 1.60% |
| Classified (Pink) | 3.20% | 1 in 31.25 | 0.32% |
| Covert (Red) | 0.64% | 1 in 156.25 | 0.064% |
| Rare Special (Gold) | 0.26% | 1 in 385 | 0.026% |
The StatTrak chance shown above is 10% of the base drop rate for each tier. So if you receive a Covert item, there's a 10% chance it will be StatTrak (0.064% overall).
How This Calculator Works
The expected count for each rarity tier is calculated using simple probability math:
Expected Value Formula
Expected Items = Number of Cases × Drop Probability
For example, opening 100 cases:
• Expected Mil-Spec = 100 × 0.7992 = 79.92 (about 80)
• Expected Knife/Gloves = 100 × 0.0026 = 0.26 (about 0-1)
This is the mathematical average - your actual results will vary due to randomness.
Understanding Variance
Due to the random nature of case openings, your actual results will differ from the expected values. The variance ranges in this calculator show the 95% confidence interval - meaning 95% of players opening that many cases would see results within that range.
This variance is calculated using the binomial distribution, which models the number of successes in a fixed number of independent trials. According to Wolfram MathWorld, for large sample sizes, this approximates a normal distribution.
Important: Expected ≠ Guaranteed
Expected values tell you what would happen on average over many, many trials. In any single session, you might get significantly more or fewer items than expected. Someone opening 385 cases has a 63% chance of NOT getting a knife, despite the "expected" value being 1. This is perfectly normal variance, not broken odds.
Why Sample Size Matters
The larger your sample size (number of cases), the closer your results will tend to be to the expected values - this is the Law of Large Numbers. With small samples, results can deviate wildly from expectations.
- 10 cases: Extremely high variance. You might see 0-2 Restricted items (expected ~1.6)
- 100 cases: Still significant variance, but averages begin to emerge
- 1,000 cases: Results typically within 10-20% of expected values
- 10,000+ cases: Results converge closely to expected rates
StatTrak Distribution
Every item that drops has exactly a 10% chance to be StatTrak, independent of its rarity. This means:
- About 10% of your total items will be StatTrak
- StatTrak distribution across rarities mirrors the base rarity distribution
- StatTrak knives/gloves are extremely rare (0.026% per case, or ~1 in 3,850)
See our StatTrak Complete Guide for more details on StatTrak mechanics and value implications.
Using This Calculator
Before Opening Cases
Use this calculator to set realistic expectations. If you're planning to open 50 cases, knowing that you should statistically expect 0.13 knives (essentially zero) helps avoid disappointment. Compare the expected total cost against the value of items you'd expect to receive using our Case ROI Calculator.
After Opening Cases
Compare your actual results to expected values to understand if you ran lucky or unlucky. Use our Luck Analyzer to get a statistical assessment of your results, or track your sessions over time with the Investment Tracker.
Budget Planning
Calculate how many cases you could afford with your budget, then see what items you'd statistically expect. This helps decide whether case opening fits your entertainment budget. Consider using our Bankroll Calculator to set responsible session limits.
Related Tools
Use these complementary tools for comprehensive case opening analysis:
- Case Odds Calculator - Calculate specific item probabilities
- Case ROI Calculator - Calculate expected return on investment
- Loot Distribution Calculator - Visualize confidence intervals
- Streak Calculator - Calculate dry streak probabilities
- Skin Goal Calculator - Plan multi-target drop goals
- Collection Completion Calculator - Estimate cost to collect all skins from a case
- Luck Analyzer - Assess your actual luck statistically
- Case Opening Simulator - Practice with virtual cases
- Case Odds Explained - Comprehensive probability guide
Frequently Asked Questions
Why don't my results match the expected values?
Expected values represent mathematical averages over infinite trials. In reality, each case opening is random, and your results will vary. The variance ranges shown account for this - your results should fall within those ranges about 95% of the time. If you've opened a small number of cases (under 100), seeing significant deviation from expected values is completely normal.
How many cases do I need to open for a knife?
At 0.26% per case (1 in 385), you'd need to open 385 cases to have an "expected" value of 1 knife. However, due to probability, after 385 cases you'd only have about a 63% chance of getting at least one knife. For a 95% chance, you'd need approximately 1,150 cases. See our Cost-to-Odds Calculator for more precise calculations.
Are StatTrak items included in the expected counts?
The main expected counts show total items regardless of StatTrak status. The StatTrak breakdown shows how many of those items you'd expect to be StatTrak (10% of each tier). For example, if you expect 80 Mil-Spec items, about 8 would be StatTrak.
Why is my expected knife count a decimal?
Expected values are mathematical averages that can be fractions. An expected value of 0.26 knives means that on average, 26 people out of 100 who open that many cases would get a knife. For any individual, you either get a knife or don't - but the average across many players would be 0.26.
Does this account for different case types?
All CS2 weapon cases use identical drop rates. The only difference between cases is their contents (which specific skins can drop), not the probability of each rarity tier. This calculator works for any standard CS2 weapon case. Special containers like Souvenir Packages use different systems.
How are the variance ranges calculated?
Variance ranges use the binomial distribution's standard deviation to calculate 95% confidence intervals. The formula is: Range = Expected ± 1.96 × √(n × p × (1-p)), where n is number of cases and p is the drop probability. This statistical method is standard for modeling success/failure outcomes.
Responsible Gaming Reminder
Case opening is gambling and has negative expected value. Most players lose money over time. Only spend what you can afford to lose as entertainment. If you're under 18, do not open cases. If gambling becomes a problem, visit BeGambleAware for support.
Last updated: January 2026