Insurance is the most misunderstood bet in blackjack. Casinos offer it when the dealer shows an Ace, and many players take it "to protect their hand." But the math tells a different story: insurance has a 5-7% house edge for basic strategy players. This guide explains exactly why, and reveals the only scenario where insurance makes sense — card counting.
📋 In this guide
🛡️ What Is Insurance in Blackjack?
Insurance is a side bet offered when the dealer's upcard is an Ace. You can bet up to half your original wager that the dealer's hole card is a 10-value card (10, J, Q, K), giving them a blackjack. If the dealer has blackjack, insurance pays 2:1.
How It Works
- Dealer shows an Ace
- You can place an insurance bet (up to ½ your original bet)
- If dealer has blackjack: Insurance pays 2:1, main bet pushes
- If dealer doesn't have blackjack: You lose insurance, main hand continues
💡 Example: You bet $20. Dealer shows Ace. You take $10 insurance. Dealer has blackjack. You lose $20 main bet? No — insurance pays $20 (2:1 on $10), so you break even. Without insurance, you'd lose $20.
This sounds like protection, but the math says otherwise. Compare to other side bets →
📊 The Math Behind Insurance
Probability Calculation (6 decks)
| Component | Value |
|---|---|
| Total cards in shoe | 312 (6 decks × 52 cards) |
| 10-value cards | 96 (16 per deck × 6) |
| Dealer shows Ace | 1 card removed (not a 10) |
| Remaining cards | 311 |
| 10-value cards remaining | 96 |
| Probability of dealer blackjack | 96/311 = 30.9% |
Fair Odds Calculation
If insurance were a fair bet, the payout would equal the inverse of the probability:
- Fair odds multiplier: 1 / 0.309 = 3.23
- Fair payout: 2.23:1 (bet $10, win $22.30)
- Actual payout: 2:1 (bet $10, win $20)
⚠️ The Casino's Edge
The casino pays you $20 when fair odds would pay $22.30. That $2.30 difference is pure profit for them — and loss for you.
🏠 Insurance House Edge
By Number of Decks
| Decks | Probability of 10 | House Edge |
|---|---|---|
| 1 deck | 16/51 = 31.4% | 5.9% |
| 2 decks | 32/103 = 31.1% | 6.2% |
| 4 decks | 64/207 = 30.9% | 6.5% |
| 6 decks | 96/311 = 30.9% | 6.5% |
| 8 decks | 128/415 = 30.8% | 6.7% |
What This Means
For every $100 you bet on insurance, you lose $5-7 on average. That's 10x worse than the main game (0.5% house edge).
📊 Comparison: Insurance's 6.5% house edge is worse than:
- Roulette (5.26% on double-zero)
- Most slot machines (3-15%)
- All other blackjack side bets except Lucky Ladies
💰 The "Even Money" Trap
When you have a blackjack and the dealer shows an Ace, the dealer will offer "even money" — a guaranteed 1:1 payout instead of playing the hand. This is just insurance in disguise.
Why It's a Trap
| Scenario | Probability | Outcome |
|---|---|---|
| Take even money | 100% | Win 1:1 ($10 bet → $10 profit) |
| Decline even money | 69.1% (dealer no BJ) | Win 3:2 ($10 bet → $15 profit) |
| Decline even money | 30.9% (dealer BJ) | Push ($0 profit) |
Expected Value Comparison
For a $10 bet:
- Even money: $10 profit guaranteed
- Decline: (0.691 × $15) + (0.309 × $0) = $10.36
⚠️ Never Take Even Money
Declining even money is worth $0.36 more per $10 bet. Over 100 such hands, that's $36 — free money you're giving the casino. Always decline.
🔢 When Card Counters Take Insurance
Card counting changes everything. Insurance becomes profitable when the remaining deck has more than the normal proportion of 10-value cards.
Insurance by True Count
| True Count | 10-Value Proportion | Player Advantage |
|---|---|---|
| 0 or negative | 30.8% | -6.5% |
| +1 | ~32% | -4% |
| +2 | ~33% | -1% |
| +3 | ~34% | +1.5% |
| +4 | ~35% | +4% |
| +5+ | 36%+ | +7%+ |
The Threshold
In most counting systems, insurance becomes profitable at a true count of +3 or higher. At these counts, more 10s remain in the deck, making dealer blackjack more likely.
🎯 Pro Tip: Serious card counters memorize the insurance index exactly. At +3, they insure all hands. Below +3, they never insure. Learn card counting →
❌ Common Insurance Mistakes
❌ "I'm protecting my hand"
You're not protecting anything — you're making a separate negative-expectation bet. The main hand's outcome doesn't affect insurance's value.
❌ "I have a good hand, so I'll insure"
Your hand doesn't matter. Insurance is purely about the dealer's hole card. Having 20 doesn't make insurance better.
❌ "Even money is safe"
Safe, but costly. Over time, declining even money earns you 3.6% more. That's a huge difference.
❌ "The dealer looks like they have it"
Dealers don't give off tells. The math is the only reliable guide.
⚠️ The Only Exception
The ONLY time insurance is correct: True count ≥ +3. If you're not counting, never take insurance. Ever.
📘 Basic Strategy for Insurance
The basic strategy rule couldn't be simpler:
NEVER TAKE INSURANCE
This includes never taking even money when you have blackjack.
Why Basic Strategy Says No
Basic strategy is mathematically optimized to minimize house edge. Insurance increases the house edge by 5-7%, so it's automatically excluded. Every basic strategy chart explicitly says "insurance = no" or "never insure."
📊 Insurance vs Other Side Bets
| Side Bet | House Edge | Verdict |
|---|---|---|
| Insurance | 5-7% | Never take (unless counting) |
| Perfect Pairs | 5-10% | Avoid |
| 21+3 | 6-11% | Avoid |
| Royal Match | 5-12% | Avoid |
| Lucky Ladies | 15-25% | Never play |
| Main Game | 0.5% | Play this |
Insurance is actually one of the "better" side bets — but "better" still means terrible. Stick to the main game. Complete side bets guide →
🧮 Calculate Insurance Odds Yourself
Use our free odds calculator to see exactly how insurance performs with different deck counts and true counts.
💰 Play at Casinos with 3:2 Blackjack
These casinos offer player-friendly rules and never push 6:5 tables. Avoid insurance, play perfect basic strategy.