Free slot calculators
Slot math, worked out for you
Find out what a bonus playthrough really costs, how long a bankroll lasts at your bet, and how RTP and volatility shape a night of spins. Built for US players, with every formula on the page.
- Three calculators, free, no sign-up and nothing to download
- A plain-language guide under every tool, with worked examples
- Independent: we list no casino offers and rank no casinos
The calculators
Pick the question you have. Each tool explains its answer.
Wagering calculator
How much you must bet before a bonus becomes cash, what that costs on average, and whether your balance is likely to last.
Open Calculator 02Session and bankroll calculator
How long a budget lasts at your bet, RTP and pace, what an hour costs on average, and how much real sessions vary.
Open Simulator 03RTP and volatility simulator
Play the same session a thousand times on three model slots with the same RTP and see how differently the nights end.
OpenWhat the numbers mean
Short guides to every term the calculators use.
Wagering calculator
How much you must bet before a bonus becomes cash, what that costs on average, and whether your balance is likely to last.
- What playthrough meansHow the requirement is counted, which bets go toward it, and what bonus only versus deposit plus bonus does to the total.
- Game contributionWhy a $1 bet on one game clears $1 of a bonus and the same bet on another clears 20 cents or nothing.
- Bonus rules that void winningsExpiry, excluded games, bet limits, fund order and cancellation: the terms that can cost you the winnings.
- Regulated US bonus termsWhat state rules require of a licensed casino's bonus terms, and the shape of a typical regulated welcome offer.
- What a bonus is worthBonus minus the house edge on the play-through, worked through for six common shapes, plus the time and risk the formula misses.
Session and bankroll calculator
How long a budget lasts at your bet, RTP and pace, what an hour costs on average, and how much real sessions vary.
- Expected loss per hourBet times spins per hour times house edge: the hourly price of a slot session, and why pace matters as much as RTP.
- Choosing a bet sizeThink in bets, not dollars: how many bets your bankroll holds decides whether a session lasts the evening.
- Spin speedTwice the spins per hour means twice the expected loss. How to measure your pace and what the rules say about speed.
- Session limitsThe deposit, spend and time limits licensed casinos must offer, how fast changes take effect, and how to size them.
RTP and volatility simulator
Play the same session a thousand times on three model slots with the same RTP and see how differently the nights end.
- What RTP meansThe long-run share a slot pays back, how regulators define it, the state minimums, and why one title can have several versions.
- Slot volatilitySame RTP, very different nights: what volatility measures, what it does to a session and how to spot it in a real game.
- Hit frequencyHow often a spin pays anything, and why a lot of those wins still leave you down on the spin.
- Short run and long runCost grows with every spin, luck grows more slowly. Why one session says almost nothing about a game's RTP.
Slot terms glossary
Plain-English definitions of every bonus, game-math and session term the calculators use, each linked to the full guide.
How the numbers are made
Every calculator uses published, checkable math: the formulas sit under each tool, and the simulators run on simple model slots we describe in full. They estimate averages and spreads. They cannot predict a session, and no calculator can turn a slot into a winning bet.
Read the editorial policy for how pages are researched and kept current, and the responsible gambling page for limits, self-exclusion and free help.