Bankroll Calculator
How large does my bankroll need to be to survive a session of this length?
Open and embedCALCULATORS · CHECKED 2026-08-23Gambling maths,
Gambling maths,
shown working.
Solaspins publishes eight gambling calculators: wagering requirements, bonus value, house edge, RTP, bankroll, Kelly, odds conversion and parlays. Each one prints its formula, shows a worked example in plain HTML, and states what it cannot tell you. Every calculator is free to embed. Checked 2026-08-23.
Open a calculator÷
01Every calculator,
Every calculator,
and its answer.
Each one answers a single question and prints every line of its arithmetic underneath the answer. The fourth column is what that page's own worked example returns — the figure it is prepared to be quoted on.
| # | Calculator | What it returns | Worked example | Checked |
|---|---|---|---|---|
| 01 | Bankroll CalculatorHow large does my bankroll need to be to survive a session of this length? | Bankroll the session needs | 352.10 | 2026-08-23 |
| 02 | Bonus Value CalculatorWhat is a casino bonus actually worth once the wagering is cleared? | What the bonus is worth | −180.00 | 2026-08-23 |
| 03 | House Edge CalculatorWhat is the house edge on this game, and what does it cost me per hour? | House edge | 4.00% | 2026-08-23 |
| 04 | Kelly Criterion CalculatorHow much of my bankroll should I stake on a bet I believe has an edge? | Stake this bet deserves | 41.82 | 2026-08-23 |
| 05 | Odds ConverterWhat is this price in decimal, fractional and American odds, and what chance does it imply? | Implied probability of this price | 40.00% | 2026-08-23 |
| 06 | Parlay CalculatorWhat does a parlay pay, and what chance does the price give it? | Total return on the parlay | 70.19 | 2026-08-23 |
| 07 | RTP CalculatorWhat does an RTP figure actually mean for my money over a session? | Expected return over the session | 480.00 | 2026-08-23 |
| 08 | Wagering Requirement CalculatorHow much do I have to stake before a bonus can be withdrawn? | Total stakes required | 7,000.00 | 2026-08-23 |
HOW THESE ARE BUILTThe arithmetic is
The arithmetic is
the product.
A calculator that hides its formula is asking to be trusted rather than checked, which is the opposite of what a calculator is for. Every page here prints the formula it runs, says which of its inputs are facts and which are your assumptions, and ends on what it cannot tell you.
| Rule | What it means on the page |
|---|---|
| The formula is printed | In full, under the result, in the notation the arithmetic actually runs in. Nothing here is a black box. |
| The worked example is computed, not typed | The build runs each calculator over its own example inputs and refuses to publish the page if the printed answer and the computed one differ. The static HTML and the live form are one implementation. |
| The limits are stated | Every calculator has something it cannot see — a term in the small print, a distribution that is not normal, a probability that is your estimate rather than a fact. Each page names its own. |
02Take one
Take one
with you.
Every calculator carries an iframe snippet on its own page. No charge, no account, and no script of ours running on your site — the frame is inert, and the attribution link sits outside it in your own markup.
Bonus Value Calculator
What is a casino bonus actually worth once the wagering is cleared?
Open and embedHouse Edge Calculator
What is the house edge on this game, and what does it cost me per hour?
Open and embed03Questions about
Questions about
the calculators.
Do the Solaspins calculators work without JavaScript?
Yes. Every calculator is rendered on the server already holding its worked example, so the page a crawler or a text browser fetches contains a filled-in form, a computed answer and the full arithmetic as a table. JavaScript recalculates when you type; it is not needed to read the page.
Are the calculators free to embed on another site?
Yes, on every one of them. Each tool page carries an iframe snippet that may be pasted into any site at no charge and with no account. The snippet keeps an attribution link outside the frame, in the embedding page's own markup, so readers can reach the full calculator.
Where do the formulas come from?
Each page prints its own formula in full, above the worked example, so it can be checked rather than trusted. Most are definitions: house edge is 100 minus RTP, and a parlay multiplies its legs. The Kelly criterion is attributed in the prose to J. L. Kelly Jr.'s 1956 paper in the Bell System Technical Journal, and the bankroll page states plainly which of its inputs is an assumption you supply rather than a figure anybody measured.