Play the turn.
Trust the numbers.
Fast, transparent math tools for ONE PIECE Card Game players who want cleaner attacks, better keeps, and fewer hopeful counters.
Runs in your browser. No account. No decklist upload. No card database.
Three tools. One clearer turn.
Each tool answers one job at the table. Set the facts you know, state your assumptions, and get the arithmetic without an opaque card database.
Lethal Calculator
Map active attackers, available DON!!, life, and the counters you expect. Get a practical pressure sequence and see where the declared pool breaks.
BOARD → DON!! → LINE Plot the attackDraw Probability
Use hypergeometric math to estimate when you will see your pieces, including extra looks from searchers and your one opening redraw.
DECK → LOOKS → ODDS Chart the oddsCounter Battle
Find the smallest counter package that survives an attack, then estimate the chance an unknown hand can actually have it.
POWER → GAP → ANSWER Test the counterMath only is a feature.
OPTCGTools does not pretend to know every list, every trigger, or every line of card text. It gives you stable game math and makes the assumptions visible.
Your state stays yours
Inputs are calculated locally in the browser. There is no sign-in, telemetry, or saved game state.
Rules snapshot, not vibes
Method notes link back to the official Comprehensive Rules and carry a versioned snapshot date.
Assumptions up front
Blockers, triggers, card-specific effects, and unknown Life cards are called out instead of silently guessed.
How OPTCGTools handles a game state
The tools follow the current rules snapshot for the basic framework: 50-card decks, a 10-card DON!! deck, five-card opening hands with one redraw, +1000 power per given DON!! during your turn, and counters played in the Counter Step. Card text can override the general rules, so a calculator result is always a starting point - not a ruling for a card-specific interaction.
Read the rules snapshot and methodology before relying on a narrow edge case.
Does this have a card database?
No. That is deliberate. These are fast, portable math tools for a board state you enter yourself; they do not need to scrape, store, or guess your deck.
Can a calculator promise a lethal through unknown Life cards?
No. The lethal tool reports what follows from the counter pool you declare. If the opponent has Life remaining, a successful hit adds a Life card to hand and may reveal a Trigger, so the site labels that distinction.
Are you affiliated with the ONE PIECE Card Game?
No. OPTCGTools is an independent fan-made math utility and is not affiliated with Bandai, Shueisha, or the ONE PIECE Card Game.