Rex says
The fast lane for the math you almost remember from school. Type the numbers, get the answer, move on with your day.
Try a scenario
Click to load — tweak from there.Inputs
Result
1-unit bet size
$30.00
0.5-unit bet size
$15.00
2-unit bet size
$60.00
3-unit bet size
$90.00
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter total betting bankroll ($).
- 2Enter unit size as % of bankroll (%).
- 3Read your 1-unit bet size on the right — it updates as you type.
- 4Hit Share to keep the scenario or send it to someone.
About this calculator
Flat unit staking means betting the same percentage of your bankroll on every wager (adjusted for confidence tier) rather than picking arbitrary dollar amounts that drift with recent wins or losses. Most disciplined bettors define a 'unit' as 1-2% of total bankroll, then size individual bets in units (a 1-unit play, a 2-unit 'best bet', etc.) instead of dollar figures, which keeps sizing proportional as the bankroll grows or shrinks. This calculator converts your bankroll and chosen unit percentage into a dollar unit size, then shows what 0.5, 1, 2, and 3-unit bets look like so you can size a specific wager by confidence level without recalculating percentages every time. It also flags when your unit size is aggressive relative to standard bankroll management guidance (generally under 5% per unit) so you can catch oversized bets before they turn one bad week into a serious bankroll hit.
Worked example
Using the values the calculator loads with:
Inputs
- Total betting bankroll: 2000 $
- Unit size as % of bankroll: 1.5 %
Results
- 1-unit bet size: $30.00
- 0.5-unit bet size: $15.00
- 2-unit bet size: $60.00
- 3-unit bet size: $90.00
What each field means
Inputs
- Total betting bankroll ($)
- The total betting bankroll used in the calculation, measured in $. Starts at 2000 $ so you have a working example on load.
- Unit size as % of bankroll (%)
- The unit size as % of bankroll used in the calculation, measured in %. Starts at 1.5 % so you have a working example on load. Accepted range: 0.1–10 %.
Results
- 1-unit bet size
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- 0.5-unit bet size
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- 2-unit bet size
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- 3-unit bet size
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
What unit percentage do most disciplined bettors use?
1-2% of total bankroll per unit is the most commonly recommended range in bankroll management guides, with 'max bet' plays rarely exceeding 3-5 units even on high-confidence spots. Going much above 5% per single bet meaningfully raises risk of ruin even with a real edge, as shown by standard gambler's-ruin modeling.
Should I resize my unit after a winning or losing streak?
Recalculating unit size off your current bankroll periodically (weekly or monthly, not after every single bet) keeps sizing proportional without letting a hot streak tempt you into oversized bets or a cold streak force you into unit sizes so small they don't matter. Constant recalculation after every bet, called 'variable unit sizing tied to a shrinking bankroll,' can also accelerate losses in a bad streak if not capped.
Is flat unit sizing better than Kelly-based sizing?
Flat sizing is simpler and more forgiving of probability-estimate errors, since it doesn't require a precise edge input the way Kelly sizing does. Kelly sizing can theoretically grow a bankroll faster with a genuinely known edge, but it's also more sensitive to overestimating that edge. Many bettors use flat units specifically because it's harder to blow up from a bad probability estimate.
Accuracy and limitations
- Results are rounded for display; the underlying calculation keeps full precision.
- Very large or very small inputs may hit floating-point limits in the browser.
- Inputs outside the accepted range are clamped rather than rejected.
Related tools
Bankroll Risk of Ruin Calculator
Estimate the odds of busting your bankroll at a given edge and bet size.
Expected Value (EV) Bet Calculator
Find the dollar EV of a wager given your true win probability.
Break-Even Win Rate Calculator (-110 and Beyond)
The win percentage you need at any odds just to break even.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Betting Unit Size Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/betting-unit-size-calculator
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/betting-unit-size-calculator" target="_blank" rel="noopener">Betting Unit Size Calculator — RevenueLab</a> (2026).</p>
Source: [Betting Unit Size Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/betting-unit-size-calculator) (2026).