M and big blinds
M Ratio to Big Blinds: What M 10 Means With and Without Antes
M 10 is 25 big blinds at a table with a big blind ante. With no ante it's 15, and with an old-style ante of an eighth of a big blind from all 9 players it's 26.3. Turn it round and the same 25 big blind stack is M 16.7, 10 or 9.5, depending only on the ante.
To convert, multiply M by what one orbit costs in big blinds: 2.5 with a big blind ante, 1.5 with none. To go back, divide. If you'd rather type in the real blinds and your stack, the M-ratio calculator does it. The tables below are for doing it in your head.
Our own site counts both ways. The push/fold chart works in big blinds and the lessons teach M, so the last part of this page reads one in terms of the other.
What one orbit costs in big blinds
Each time the button goes round, you post both blinds once, plus your share of the antes.
- No ante: 1.5 big blinds, the half blind and the full one.
- Big blind ante: 2.5, since one ante the size of the big blind goes on top of the 1.5. It started at ARIA in 2017. By 2019 the WSOP used it in every no-limit hold'em event, and by 2020 it was the norm on most live tours.
- Classic ante of 12.5% from each of 9 players: 9 × 0.125 is 1.125, so an orbit costs 2.625. That was the usual live size before the big blind ante. The 2015 WSOP $1,000 events ran antes of 25 at 100/200 and 100 at 400/800.
M to big blinds: how many big blinds is M 10?
The zone column is Harrington's zone at that M. The classic column is a 12.5% ante at a nine-handed table.
| M | Zone | No ante | BB ante | Classic, 9 players |
|---|---|---|---|---|
| M 1 | Red | 1.5 BB | 2.5 BB | 2.6 BB |
| M 5 | Red | 7.5 BB | 12.5 BB | 13.1 BB |
| M 6 | Orange | 9 BB | 15 BB | 15.8 BB |
| M 10 | Yellow | 15 BB | 25 BB | 26.3 BB |
| M 15 | Yellow | 22.5 BB | 37.5 BB | 39.4 BB |
| M 20 | Green | 30 BB | 50 BB | 52.5 BB |
M 10 is the line between orange and yellow. With a big blind ante it falls at 25 big blinds, which is also where our push/fold chart stops. A classic ante moves with the table: six-handed, M 10 is 22.5 big blinds.
Sources don't agree which side of the line M 10 itself is on. Wikipedia puts it in yellow and PokerStrategy's glossary puts it in orange. Our calculator and lessons call it yellow. The same split happens at M 20, 6 and 1, and it only matters if your stack lands exactly on the number. Some pages, ours included, also write the red zone as M 1 to 5. Read that as anything under 6: orange starts at M 6.
Big blinds to M: what M is 20, 25 or 30 big blinds?
| Stack | No ante | BB ante | Classic, 9 players |
|---|---|---|---|
| 10 BB | M 6.7 (Orange) | M 4 (Red) | M 3.8 (Red) |
| 15 BB | M 10 (Yellow) | M 6 (Orange) | M 5.7 (Red) |
| 20 BB | M 13.3 (Yellow) | M 8 (Orange) | M 7.6 (Orange) |
| 25 BB | M 16.7 (Yellow) | M 10 (Yellow) | M 9.5 (Orange) |
| 30 BB | M 20 (Green) | M 12 (Yellow) | M 11.4 (Yellow) |
| 40 BB | M 26.7 (Green) | M 16 (Yellow) | M 15.2 (Yellow) |
| 50 BB | M 33.3 (Green) | M 20 (Green) | M 19 (Yellow) |
A big blind ante cuts your M by 40% at the same blinds, and a classic ante nine-handed cuts it by 43%. Twenty big blinds is M 13.3 with no ante, in the yellow zone. Add a big blind ante and it's M 8, orange, and Harrington's advice changes from tighten up to be the first raiser in. The lesson on what antes do to M plays a button steal at M 9 with antes in.
How to calculate M with a big blind ante
Count the ante once per orbit. The player in the big blind posts it for the whole table, and you are that player one hand in every orbit. So the orbit is small blind, big blind and one ante: 2.5 big blinds when the ante matches the big blind.
The glossary definitions we checked were written for classic antes and don't mention the big blind ante. PokerStrategy's says to multiply the ante by the number of players, and Wikipedia's worked example does the same. Do that with a big blind ante at a full table and 25 big blinds comes out as M 2.4, not 10. A 2019 PokerNews column by Martin Harris counts it once: 400,000 chips at 10,000/20,000 with a 20,000 ante is M 8, which is 20 big blinds divided by 2.5.
The 2.5 also assumes the ante is a full big blind, which it usually is. Single-ante formats have been cut short-handed, though. In 2018 partypoker's live events had the button post one ante for the table and halved it to the size of the small blind once three or more seats were empty. Counted the same way, a half ante makes the orbit 2 big blinds.
Big blind ante vs classic ante
Eight-handed, the two formats cost exactly the same. Eight players each posting 12.5% of a big blind put in one big blind a hand, which is what a big blind ante is. Nine-handed the classic ante comes to 1.125 and ten-handed 1.25, so the last two columns barely move apart at a full table.
Effective M at a short table
The total of a classic ante shrinks as players bust, because fewer people post it. A big blind ante usually stays a full big blind to the end. Three-handed it's still a full big blind every hand, and you post it every third hand.
Harrington's fix for short tables is effective M: your M times the number of players, divided by ten. That comes to the number of hands you could fold through, divided by ten, so even a full nine-handed table takes 10% off.
| Players | BB ante | Classic ante | ||
|---|---|---|---|---|
| M | Effective M | M | Effective M | |
| 9 | 10 | 9 | 9.5 | 8.6 |
| 6 | 10 | 6 | 11.1 | 6.7 |
| 3 | 10 | 3 | 13.3 | 4 |
Six-handed with a big blind ante, 25 big blinds is still M 10 on paper and an effective M of 6, the bottom of orange. Three-handed it's an effective 3, push or fold. A classic ante would have left you 4. The lesson on effective M at a short table plays a five-handed version.
Reading our push/fold chart in M
The push/fold chart is solved with a big blind ante, so divide its stacks by 2.5. Its 25 big blind top is M 10, and the red zone runs from 2.5 big blinds up to 15, where orange starts. For how wide each seat shoves across that range, see the shove percentages by seat.
The lessons price their hands with classic antes. In Computing your M, 14,700 chips at 400/800 with a 100 ante is 18.4 big blinds and M 7. Under a big blind ante the same stack would be M 7.4.
Quick answers
How many big blinds is M 10?
25 with a big blind ante. With no ante it's 15, and with a classic 12.5% ante it's 26.3 nine-handed or 22.5 six-handed. It's the edge between orange and yellow.
Is M 10 the same as 10 big blinds?
No. Ten big blinds with a big blind ante is M 4, which is red. You'd need 25 for M 10.
What M is 20 big blinds?
M 8 with a big blind ante, M 13.3 with no ante, and M 7.6 with a classic 12.5% ante nine-handed.
How many big blinds is the red zone?
Between 2.5 and 15 big blinds with a big blind ante, or between 1.5 and 9 with no ante. Fifteen big blinds with a big blind ante is M 6, which is already orange.
To run your own stack and blinds, use the M-ratio calculator.
Sources
- Musing about M and the big blind ante, Martin Harris, PokerNews, 2019: the 20,000 ante worked example.
- All no-limit hold'em events to use big blind ante in 2019, Card Player.
- The big blind ante, Greg Raymer, Card Player, 2020.
- Big blind ante becomes the standard, PokerNews' top stories of 2018: ARIA, and partypoker's half ante.
- Picturing Day 1 structures at the low buy-in WSOP events, PokerNews: the 2015 classic ante sizes.
- M-ratio, Wikipedia, and M, the PokerStrategy glossary: the zone edges and the classic ante calculation.
- Harrington on Hold'em, Volume II: The Endgame, Dan Harrington and Bill Robertie, 2005: M, the zones and effective M.