Real chip placement, not a coverage slider
Most roulette calculators ask how many numbers you cover and stop there. The Survival Lab works from the actual table. Every chip sits on a legal position — a straight-up, split, street, corner, six-line, dozen, column or even-money box — with that bet's real payout. A split pays 17 to 1 on two numbers; a six-line pays 5 to 1 on six. Build the layout you would actually play, with the stakes you would actually use, and the lab settles all of it together on every pocket of the wheel: 37 on a European single-zero table, 38 on an American double-zero table.
Why coverage isn't the same as profit
Covering a number only means one of your chips wins when it lands. Whether the spin made money depends on everything else on the table. Put $1 on red, $0.50 on the six-line 1–6 and $0.50 on the corner 25/26/28/29 and you cover 24 of 37 pockets — but red 7 pays back your $1 red bet plus $1 profit while the other two chips lose, so the spin nets exactly $0. In that layout 14 covered pockets are pushes, only 10 are net wins, and 13 lose outright. The lab shows all three counts so a high hit rate can't hide a thin profit rate. Find your strategy's nemesis walks through this exact layout.
How the losing streak calculator works
Once each pocket is settled, the chance that a spin is a net loss is simply the losing pockets over the wheel — 13 of 37 in the example. From there the lab computes the exact probability of seeing at least one run of a given length inside your session, accounting for runs that overlap. Over 150 spins the example has a 16.39% chance of at least one run of six or more net losses in a row. That is the chance of a streak, not the chance of going broke: what a streak costs you depends on your stakes, your progression and where you set your stop.
How a progression changes your bankroll exposure
A progression raises the bet after a loss so that one win can claw back the run. It also multiplies what each loss costs. Double the example layout after every losing spin from a $200 bankroll and the wagers run $2, $4, $8, $16, $32, $64 — six losses, $126 gone — and the seventh wager of $128 can't be covered by the $74 left. The lab draws that ladder for flat betting, doubling, D'Alembert, Fibonacci or a custom ladder, shows where your stop-loss ends the session first, and shows which pockets genuinely recover the run and which only win back part of it. Sizing a bankroll properly works through the arithmetic.
Stress-test a bankroll without betting a cent
Every calculation runs on your own device. Set your bankroll, session length, profit target and stop-loss, then run thousands of simulated sessions from a seed you can share, so anyone can replay exactly the same sessions. The report lays out the payout table, the streak odds, the progression ladder, your strategy's nemesis — the losing pattern it is most exposed to — and the simulation results, ready to print or save as a PDF.
What the free lab does, and what VIPER adds
The Survival Lab measures the mathematical exposure of one betting layout on a fair wheel. VIPER, our full roulette strategy platform, goes further: strategies that change their bets as the table moves, backtests against real recorded spin history, session discipline enforced for you at the live table, and the AI Wizard to build strategies from a description. Use the lab to understand a layout's risk; use VIPER when you want to test and play a complete strategy.
Does the calculator predict roulette spins?
No. Every spin is treated as independent, with each pocket equally likely. The lab tells you what your layout pays on every possible result and how often bad stretches arrive — never which number comes next.
Is the streak percentage my chance of going broke?
No. It is the chance that a run of net losses of that length shows up somewhere in your session. Whether a run like that breaks you depends on your stakes, your progression, your stop-loss and your bankroll — which is exactly what the progression ladder and the session simulator measure.
Can a layout cover 70% of the wheel and still lose on most spins?
Yes. Coverage counts the pockets where at least one chip wins; profit depends on the whole layout. Wide coverage built from low-paying bets often produces pushes or small net losses even when a covered number lands. The lab separates hit rate from net-win rate for exactly this reason.
Do I need an account, or does it cost anything?
No account, no email and no payment. Analysis, simulations, the printable report and the JSON and CSV downloads are free, as often as you like, because all of it runs in your browser.
Does doubling up after a loss make a layout safe?
No. A progression changes how much you stake and when, not the odds of any spin. It can turn many small wins into one large loss, and the ladder in the lab shows exactly where your bankroll or the table limit stops it.
Are the simulated spins really random?
They come from a published, seeded pseudorandom generator with every pocket equally likely, so results are reproducible from the seed. That models a fair wheel; it is not a certified casino random number generator and not a record of real spins.
Can I share my layout?
Yes. Copy Strategy Link creates a link that reopens your exact chips, bankroll, progression and rules in anyone's browser, where every number is recalculated from scratch. Challenge a Friend sends the same layout with an invitation to lower its risk without adding to the bankroll. Share via Email opens your own email app — we never send email or collect addresses.
Does my layout carry over into VIPER?
No. The lab analyses one betting layout on a fair wheel and stays in your browser. In VIPER you build the full strategy — when to bet, how stakes move, when to stop — and backtest it against real recorded spins before you play. How to read a backtest without fooling yourself covers what to check first.