Responsible gambling

By · author of the MIT-licensed teachersbettextbook library ·

Teacher’s Bet is a calculator, not a sportsbook: it takes no wagers, holds no money and issues no picks. None of that makes gambling safe. If it has stopped being entertainment, help is free, confidential and answered around the clock — the numbers are directly below.

Help, right now

1-800-GAMBLER — the national problem gambling helpline number carried in US sportsbook advertising. Free, confidential, 24 hours.

1-800-522-4700 — the National Council on Problem Gambling’s National Problem Gambling Helpline. Calls and texts, 24 hours; the network routes you to a call centre near your area code.

988 — the Suicide & Crisis Lifeline in the US, by call or text, if the situation is an emergency.

Chat, state-by-state treatment listings and resources for family members are on NCPG’s help and treatment page. Outside the United States, your national helpline will be a different number.

The signs clinicians look for

Gambling disorder has a formal diagnostic definition, and the criteria below are the plain-language version of it. They are questions, not a verdict. One “yes” is not a diagnosis and a website cannot make one either way — a clinician does that.

That list is the substance of the criteria in the DSM-5, the manual US clinicians diagnose from. If several of them land, the helpline numbers above are staffed by people whose whole job is that conversation.

Self-exclusion, limits and blocking

Self-exclusion is a voluntary ban you place on yourself, and it is enforceable in a way a resolution is not.

Teacher’s Bet cannot exclude you from anything, because it holds no account, no balance and no bet. What it can do is stay out of the way: there is no login you need to keep, no streak to protect, no leaderboard, and no notification unless you switch one on. Clearing site data in your browser deletes everything stored on your device. If you have signed in, or left an address on the pre-launch list, an account row and an email address also exist on the server — the privacy page lists exactly what is held there, and how to have it deleted.

What the math does not do

This site exists to make prices legible. That is a narrow thing, and it is worth being blunt about the limits of it.

A fair price is an estimate of a probability, not a forecast of a result. Expected value is a long-run average over many repetitions, not a statement about the next one. And when the inputs contain no edge, every calculator here prints $0 rather than rounding up into something that looks actionable — the honest zero is a product rule, not a mood.

The number most tools never show you is how ordinary a long losing run is with a real edge in hand:

A genuine edge, and a losing hundred bets

100 bets at p=51%, even money, 1 unit each100\text{ bets at } p = 51\%,\ \text{even money},\ 1\text{ unit each}
expected total=100×(0.51−0.49)=+2 units\text{expected total} = 100 \times (0.51 - 0.49) = +2\text{ units}
σ=2n p q=2100×0.51×0.49≈10 units\sigma = 2\sqrt{n\,p\,q} = 2\sqrt{100 \times 0.51 \times 0.49} \approx 10\text{ units}
W∼B(100, 0.51),total=2W−100W \sim \mathrm{B}(100,\,0.51),\quad \text{total} = 2W - 100
P(total<0)=P(W≤49)≈0.38P(\text{total} < 0) = P(W \le 49) \approx 0.38
About 38 of every 100 such stretches finish behind, and another 8 finish exactly level — with the 2% edge intact the whole way. The swing is five times the size of the edge. A losing run is not evidence that the edge is gone, and a winning one is not evidence that it exists.

Two consequences follow, and neither is comfortable. Results in the hundreds of bets say almost nothing about skill. And a bettor who reads a downswing as a signal to bet bigger is being fooled by the same arithmetic that made the downswing ordinary. That is why the sizing tools here default to half Kelly rather than full — the derivation is on the Kelly criterion page, and it shows growth going to zero at double the Kelly stake even when the edge is real.

No calculation removes risk. A better price is still a price on an uncertain event, and precision about an edge is not protection from it.

Who this site is for

Adults. The standing policy is 21 or older, and where the legal betting age where you live is higher than that, the higher number applies.

Before the live board can be used, the app shows a full-screen notice — what the site is, what it refuses to do, and a single confirmation that you are of legal betting age. Confirming stores one value in your own browser and sends nothing anywhere. No date of birth is collected and no identity check is performed, because the site holds no funds and processes no wager, so it has nothing to verify you against. That is an honest gate, not a barrier: it will not stop anyone determined to click through it.

If you are under the legal age where you live, none of this site is for you — the calculators included.

What this site will not do to you

Stated flatly, because a good deal of this industry does the opposite:

If it is someone else’s gambling

The helplines above take calls from family members too, and that is a large share of what they handle. Two peer-support organisations run free meetings in most US states and online:

The contact inbox here is not a support channel for gambling harm, and it would be a disservice to pretend otherwise. It is one person answering mail about arithmetic. The numbers at the top of this page are staffed by people trained for this.

Frequently asked questions

What is the problem gambling helpline number?

1-800-GAMBLER is the national problem gambling helpline number carried in US sportsbook advertising. The National Council on Problem Gambling also runs the National Problem Gambling Helpline at 1-800-522-4700. Both are free, confidential and answered 24 hours a day. If the situation is an emergency, the Suicide & Crisis Lifeline in the US is 988 by call or text.

What is self-exclusion?

A voluntary ban you place on yourself. Operator-level exclusion is a setting inside a sportsbook account and covers that operator. State-level exclusion is run by the gaming regulator and can cover every licensed operator in that state at once. Deposit, loss, wager and time limits and cool-off periods sit alongside it in most regulated US apps.

Can Teacher’s Bet self-exclude me?

No. It holds no account, no balance and no bet, so it has nothing to exclude you from. Self-exclusion happens with the operator holding your money, or with the state regulator. Device-level blocking software blocks gambling sites and apps. Clearing site data removes everything stored on your device; if you signed in or joined the pre-launch list, an account row and an email address also sit on the server, and the privacy page says how to have them deleted.

Does a positive expected value mean a bet will win?

No. Expected value is a long-run average, not a forecast of one result. A bettor with a genuine 2% edge at even money expects +2 units over 100 one-unit bets, but the standard deviation of that total is about 10 units — so about 38% of such stretches finish behind and another 8% finish exactly level, with the edge intact the whole way.

How old do you have to be to use Teacher’s Bet?

The standing policy is 21 or older, and where the legal betting age is higher, the higher number applies. Before the live board can be used, the app asks you to confirm you are of legal betting age; that confirmation is stored in your own browser. No date of birth is collected and no identity check is performed.

Does Teacher’s Bet earn money when I place a bet?

No. There are no affiliate links to any sportsbook or exchange, no promo codes and no paid placement anywhere on the site. No book pays to appear here.