Blackjack Betting Unit Calculator
Calculate your optimal betting unit based on bankroll size, risk tolerance, and playing style for proper blackjack bankroll management.
Formula:
Unit = min(Bankroll × Risk%, Bankroll ÷ UnitsNeeded)Recommended Unit
$100
Range: $80-$120
Max Bet
$100
1x spread
Effective Units
100
Need 100 for 13% RoR
Bankroll & Risk Settings
$
Money dedicated to blackjack
% of bankroll per unit
Playing Style
Determines required unit count
%
Your advantage (negative = house edge)
Kelly Criterion Analysis
Full Kelly
$43
Half Kelly (Safer)
$22
Half Kelly is recommended to reduce variance while maintaining growth
Bankroll Analysis
100
Effective Units
100
Units Needed
~13%
Risk of Ruin
±$1,150
Hourly Std Dev
Quick Answer
With a $10,000 bankroll, optimal betting unit is $100-$200 (1-2% of bankroll). For card counters, the unit should support spreading 1-12 units. Conservative players use 1%, aggressive 2-3%. Kelly Criterion suggests betting edge/variance of bankroll.
Key Facts
- ✓Standard recommendation: 1-2% of total bankroll per betting unit
- ✓Card counters need 200-400 units for 1-12 spread
- ✓Kelly Criterion: Bet = (edge × bankroll) / variance
- ✓$5,000 bankroll = $25-$100 optimal unit
- ✓Higher edge = larger optimal bet size
- ✓Risk of ruin decreases with smaller bet sizing
Frequently Asked Questions
What is a betting unit in blackjack?
A betting unit is your standard bet size, typically 1-2% of your total bankroll. If you have $5,000, your unit would be $50-$100. Card counters use units to scale their bets based on the count while maintaining proper bankroll management.
How do I calculate my optimal betting unit?
Divide your total bankroll by the number of units you need. For basic strategy players, 50-100 units is sufficient. Card counters spreading 1-12 need 200-400 units minimum. $10,000 ÷ 200 units = $50 unit size.
What is the Kelly Criterion for blackjack?
The Kelly Criterion calculates optimal bet size as (edge × bankroll) / variance. For blackjack with ~1% edge, Kelly suggests betting about 0.8% of bankroll. Most advantage players use "half Kelly" or "quarter Kelly" to reduce variance.
How many betting units do I need for card counting?
For a 1-12 bet spread, you need 200-400 units to have less than 5% risk of ruin. With $10,000 bankroll and $25 units, you have 400 units - very safe. With $50 units, you have 200 units - adequate but more volatile.
Try These Examples
Quick-start with common scenarios
How this works
Calculations follow the published mathematics of the game — combinatorics for cards, probability theory for dice, and expected-value accounting for wagers. Results are verified against independent references (primarily Wizard of Odds). No calculation here is an opinion or recommendation; it is arithmetic applied to the rules of the game.
What this tool can’t do
When to consult a professional
This tool computes probability and expected value. It is not a betting system and cannot predict the outcome of any individual wager. If gambling is causing problems for you or someone you know, call the National Problem Gambling Helpline at 1-800-GAMBLER.
Sources
- [1]Wizard of Odds — Michael Shackleford, ASAIndustrywizardofodds.comAccessed Apr 21, 2026
Actuary; widely cited casino-game probability reference. Used for house-edge and EV verification.
- [2]National Council on Problem GamblingOfficial sourcencpgambling.orgAccessed Apr 21, 2026
Responsible-gambling guidance and 1-800-GAMBLER helpline.
Joseph OrdunaFounder & Software Engineer
Full-stack software engineer specializing in embedded systems, web architecture, and AI/ML. Founder of Practical Web Tools. Built the gesture-controlled drone IP acquired by KD Interactive (Aura Drone, sold on Amazon).
Recommended Unit
$100
Range: $80-$120
Max Bet
$100
1x spread
Effective Units
100
Need 100 for 13% RoR