Poker M-Ratio Calculator: Navigate Tournament Zones

M-ratio measures how many orbits you can survive at current blind levels, revolutionizing tournament strategy. Our calculator computes your M, identifies your zone, and recommends optimal play adjustments based on your stack's tournament health.

What Is M-Ratio?

M-ratio (or M-number) represents how many rounds of blinds and antes your stack can sustain before being blinded out. Popularized by Dan Harrington, it's the essential metric for tournament stack assessment.

Quick Answer: M = Stack / (SB + BB + Antes). With 10,000 chips at 200/400 blinds with 50 antes (9-handed), your M = 10,000 / (200 + 400 + 450) = 9.5. This puts you in the "Orange Zone" (M 6-10) where you should be looking to resteal and avoid marginal situations. Below M=5, you're in push/fold territory.

How to Use Our M-Ratio Calculator

Use the Poker M-Ratio Calculator →

Enter your stack and blind structure to see your M and strategic recommendations.

Step-by-Step Instructions

1. Enter Stack Size: Your chip count

2. Enter Blinds: Small and big blind

3. Enter Antes: Per-player ante

4. Select Table Size: Players for ante calculation

5. View M and Zone: Strategic category

Input Fields Explained

Field	Description	Example
Stack	Your chips	15,000
Small Blind	SB amount	300
Big Blind	BB amount	600
Ante	Per player	75
Table Size	Active players	9
M-Ratio	Orbits remaining	10.7
Zone	Strategy category	Orange

M-Ratio Formula

Standard Calculation

M = Stack / (SB + BB + (Ante × Players))

Example:
Stack: 20,000
Blinds: 400/800
Ante: 100 × 9 players = 900
M = 20,000 / (400 + 800 + 900) = 9.5

Effective M (Short-Handed)

When table is short-handed, calculate Effective M:

Effective M = M × (Players / Full Table)

6-handed at 9-max table:
Effective M = 9.5 × (6/9) = 6.3

Harrington's Zones

Zone Classification

Zone	M Range	Color	Strategy
Green	20+	Safe	Full strategy available
Yellow	10-20	Caution	Tighten up, avoid marginal
Orange	6-10	Danger	Resteal, first-in aggression
Red	1-5	Critical	Push/fold mode
Dead	<1	Terminal	All-in only

Green Zone (M 20+)

Aspect	Recommendation
Open range	Full range
Position	All positions playable
Speculative hands	Profitable to play
Post-flop	Full flexibility

Yellow Zone (M 10-20)

Aspect	Recommendation
Open range	Tighten 10-15%
Small pairs	Less profitable
Suited connectors	Marginal
3-betting	For value and strong semi-bluffs

Orange Zone (M 6-10)

Aspect	Recommendation
Open range	First-in aggression only
Calling	Rarely correct
Resteals	Primary weapon
All-in threshold	More frequent

Red Zone (M 1-5)

Aspect	Recommendation
Strategy	Push or fold only
Hand selection	Top 30-50% of hands
Position	Critical factor
Calling	With premium only

Real-World Examples

Example 1: Healthy Stack

Stack: 45,000 Blinds: 600/1,200 Ante: 200 × 9 = 1,800 Total orbit: 3,600

M = 45,000 / 3,600 = 12.5

Zone: Yellow Strategy: Play normally but avoid marginal spots. Don't call light. Look for spots to accumulate.

Example 2: Short Stack

Stack: 12,000 Blinds: 500/1,000 Ante: 100 × 8 = 800 Total orbit: 2,300

M = 12,000 / 2,300 = 5.2

Zone: Red (borderline) Strategy: Push/fold. Look for first-in opportunities from late position. Don't wait for premiums.

Example 3: Desperate Stack

Stack: 4,500 Blinds: 800/1,600 Ante: 200 × 7 = 1,400 Total orbit: 3,800

M = 4,500 / 3,800 = 1.2

Zone: Dead Strategy: Shove any reasonable hand immediately. Can't afford to wait another orbit.

M-Ratio vs Big Blinds

Why M Is Better

Situation	BBs	M	Reality
No antes	15 BB	10	M more accurate
With antes	15 BB	7	BBs misleading
Turbo antes	15 BB	5	BBs very misleading

Conversion Approximation

Structure	M ≈ X BB
No antes	M ≈ 0.67 × BB
Standard antes	M ≈ 0.5 × BB
Big antes	M ≈ 0.4 × BB

Push/Fold Strategy by M

M = 5 (Red Zone)

Position	Push Range
UTG	22+, A9+, KQ
MP	22+, A7+, KT+, QJ
CO	22+, A2+, K8+, Q9+, JT
BTN	22+, A2+, K2+, Q7+, J8+, T8+
SB	22+, A2+, K2+, Q2+, J4+, T6+

M = 3 (Critical)

Position	Push Range
UTG	Any pair, A5+, KJ+
MP	Any pair, A2+, KT+, QJ
CO	Any pair, A2+, K5+, Q8+, J9+
BTN	40%+ of hands
SB	50%+ of hands

M = 1.5 (Desperate)

Position	Push Range
Any	Push almost anything first-in
Against open	Need strong hand
Note	Survival requires doubling up

Adjusting for Table Dynamics

Effective M at Short Tables

Table Size	M Adjustment
9-handed	Full M
6-handed	M × 0.67
4-handed	M × 0.44
3-handed	M × 0.33
Heads-up	M × 0.22

Stack Distribution Factors

Factor	M Adjustment
Aggressive table	Play tighter M thresholds
Passive table	Can wait slightly longer
Big stacks behind	Reduce resteal frequency
Short stacks behind	More fold equity

Common M-Ratio Mistakes

1. Using Only Big Blinds

Mistake: "I have 15 big blinds" Problem: Ignores antes, misleading in late stages Fix: Always calculate true M

2. Zone Transitions Too Late

Mistake: Playing Green Zone strategy at M=8 Problem: Bleeding chips with marginal hands Fix: Adjust strategy at zone boundaries

3. Ignoring Effective M

Mistake: Same M strategy at full vs short table Problem: Short-handed M is lower Fix: Calculate effective M for table size

4. Push/Fold Too Early

Mistake: All-in at M=12 Problem: Still have post-flop playability Fix: Yellow zone allows normal opens

Frequently Asked Questions

When should I switch to push/fold?

Below M=10, start incorporating more all-in plays. Below M=5, pure push/fold is correct. Context matters—aggressive tables require earlier adjustments.

Does M matter in cash games?

No. M is specifically for tournaments where blinds increase. Cash games use big blind count and stack-to-pot ratio.

How does M affect bubble play?

Low M players have less fold equity near bubbles. High M players can exploit this with wider stealing ranges.

Should I calculate M every hand?

Know your approximate M at all times. Recalculate when blinds increase or after significant pots.

What's more important: M or position?

Both matter. Low M makes position more critical because you can't see flops profitably—need first-in aggression.

How do antes affect M?

Significantly. Standard antes reduce M by 30-40% compared to no-ante calculation. Always include antes.

Advanced M Concepts

Future M Planning

Next Level M = Current Stack / Next Level Orbit Cost

Plan your stack's M at upcoming levels

Tournament Life Expectancy

Current M	Expected Orbits	With Doubles
20	20	40+
10	10	30+
5	5	15+
2	2	6+

M and ICM

M Level	ICM Consideration
High M	Less ICM pressure
Medium M	ICM starts mattering
Low M	ICM critical
Desperate	Survival > ICM

Pro Tips

• Know your M always: Glance at blinds, estimate orbits

• Plan ahead: Know M at next level

• Zone boundaries matter: Adjust at 20, 10, 5

• Include all antes: Don't underestimate orbit cost

• Effective M at short tables: More urgent than raw M

Related Calculators

• Push/Fold Calculator - Optimal shove ranges
• ICM Calculator - Tournament equity
• Poker Bankroll Calculator - Tournament buy-ins
• Tournament Payout Calculator - Prize structure
• Poker Variance Calculator - Downswing risk

Conclusion

M-ratio transforms tournament poker from guesswork to precision. Our calculator computes your M instantly, identifies your zone, and guides strategy adjustments. Understanding M means knowing when to open up, when to tighten, and when pure push/fold is your only option. Every tournament player should internalize these zones and check their M constantly as blinds increase.

Calculate Your M-Ratio Now →

Dan Harrington's M system revolutionized tournament poker by quantifying stack pressure. Our calculator makes M assessment instant, letting you focus on the strategic decisions that follow. Know your zone, play accordingly, and watch your tournament results improve.