Realistic shuffled-hand math
The simulator deals random opening hands using the same hypergeometric mechanics that govern Yu-Gi-Oh! shuffling. Run hundreds of thousands of simulated hands to converge on the true odds of opening your combo.
Probability tool
Yu-Gi-Oh! Combo Probability Simulator
Estimate how often you open your combo pieces in your starting hand. Configure 2-card combos and 1-card starters, sweep across deck sizes from 40 to 60, and simulate thousands of shuffled opening hands directly in your browser — no sign-in required.
Combo hand simulator
Up to 10M shuffled opening hands per run, executed in a Web Worker so the UI stays responsive.
Multi-pair support
Track combined open rates and per-pair odds across as many 2-card combos as you need.
Deck-size sweep
Compare 40 to 60 card decks side-by-side to see how trimming changes consistency.
100% in-browser
No server round-trips, no sign-in. Import a .ydk file and start crunching numbers.
1
Deck setup
Tell the simulator how big your deck is, how many cards you draw, and how many 1-card starters you run.
Deck size sweep
Range of main-deck sizes to simulate side-by-side.
Opening hand sizes
Compare two hand sizes (5 = going first, 6 = going second).
1-card starters
Count of cards that begin a combo on their own.
Iterations
More iterations = tighter confidence. 200K+ runs in a worker.
2
Combo pairs
Each row models a 2-card combo. The simulator reports the odds of opening at least one copy of both cards together.
| Card A | Copies | Card B | Copies | |
|---|---|---|---|---|
Pairs with both cards filled and copies > 0 are included in the simulation.
3
Import a .ydk deck
OptionalUpload a .ydk file to pull in your main-deck cards and one-click them into combo pair slots.
4
Run the simulation
Heavy runs (200,000+ iterations) execute in a Web Worker so the UI stays responsive.
Combo pieces0
Starters0
Blanks @ 4040
Iterations1,000,000
Add at least one complete combo pair or set a non-zero starter count.
Results will appear here
Configure your combo pairs, set deck-size and hand-size parameters, then run the simulation to see opening probabilities for every deck size in the sweep.
Stress-test your combo lines with hypergeometric math
The combo probability simulator turns Yu-Gi-Oh! deck-building intuition into hard numbers. Configure starters and combo pairs, sweep across deck sizes, and let the Yu-Gi-Oh! Combo Hand Simulator reveal how often the deck actually opens what it claims to.
Built for combo deck testing
Test 2-card combos one at a time or stack multiple pairs together with 1-card starters to measure how often any combo opens — the metric most modern decks live or die by.
Compare deck sizes at a glance
Sweep across 40 to 60 card decks in a single run to see the exact cost of every extra card, so you can decide whether 41 cards is really worth the trade.
How to run an accurate combo probability test
- 1Configure deck settings: minimum and maximum deck size, hand sizes (typically 5 and 6), simulation iterations, and the count of 1-card starters.
- 2Add 2-card combo pairs and pick the number of copies of each card you run. Pair names can be typed in or pulled from the autocomplete database.
- 3Optionally import a .ydk file to pull in your deck's main-deck card list and one-click-add cards into combo slots.
- 4Run the simulation. Heavy iteration counts (200,000+) run in a Web Worker so the UI stays smooth; results stream in by deck size.
Combo simulator FAQs
How does the Yu-Gi-Oh! combo probability simulator work?
It simulates thousands of shuffled Yu-Gi-Oh! decks and deals each one an opening hand. For every hand the simulator checks whether at least one copy of each card in your configured combo pair shows up, or at least one 1-card starter. The fraction of successful hands is the estimated open rate.
How many iterations should I use for accurate combo probability?
100,000 iterations are usually enough to get rates within ~0.3% accuracy. For tighter confidence intervals or rare combos, 1,000,000+ iterations are recommended — heavy runs are offloaded to a Web Worker so the page stays responsive.
What is a 1-card starter and how is it counted?
A 1-card starter is any card that begins a combo by itself. The simulator's starter slot represents the total count of such cards in the deck (e.g. set 5 if you run 3 copies of one starter and 2 copies of another). Any opening hand containing at least one starter is treated as a combo hand.
Can I test multiple combo pairs at the same time?
Yes. Add as many 2-card pairs as you need. The simulator reports per-pair open rates and an overall "any combo" rate that combines all configured pairs with your 1-card starter count.
Does the simulator support going-second hand sizes?
Yes. The hand size 1 and hand size 2 inputs default to 5 and 6 (going first vs. going second in OCG/TCG), but you can set them to any value from 1 to 20 to model alternate formats or hand traps.
How do I import a deck from EDOPro or Master Duel?
Export your deck as a .ydk file from EDOPro, YGOPro, or any compatible tool, then use the .ydk Import panel. Card names are resolved against the YGO Combo Builder card database and can be one-click-added to your combo pair slots.