Formula for back/lay odds conversion

Pages: [1] 2
 Author Topic: Formula for back/lay odds conversion  (Read 16388 times)
Namnam
Gaining experience

Karma: -3
Posts: 47

« on: December 12, 2014, 08:18:53 PM »
0

Hey guys! Sometimes I need (or want) to know the equivalent back odds for my laybet. I have found a online calculator to help me with this (http://www.bettingtools.co.uk/back-lay-equivs) but its only 2 decimals and I would prefer to have the actual formula so I can insert it in Excel. I have found the following formula: LAYODDS = 1 + ( 1/(BACKODDS-1) ). However, this does not work well in excel, since it gives back the answer in % and not decimal odds. Does anyone have the correct formula that also works in excel? If I were a math pro, I'm sure I could just figure it out by myself, but unfortunately I'm not...
 Logged
ppintaluba
Totally Pro

Karma: 37
Posts: 645

« Reply #1 on: December 12, 2014, 09:42:41 PM »
0

The formula is correct, and there's no need to be a math pro
If it shows a % it may be a formatting problem in the excel.
Just select the cell with the formula, right click the mouse and choose format cells and then choose category "number" and select 3 or 4 decimal places.
Just in case, if you also want to consider commission, you can adjust the back odds like this:
1 + (odds - 1) * (1 - commission).
You will find out the real odds you get after commission.
 Logged

Smart Bet Tracker
www.smartbettracker.com
Namnam
Gaining experience

Karma: -3
Posts: 47

« Reply #2 on: December 14, 2014, 02:19:35 PM »
0

The formula is correct, and there's no need to be a math pro
If it shows a % it may be a formatting problem in the excel.
Just select the cell with the formula, right click the mouse and choose format cells and then choose category "number" and select 3 or 4 decimal places.
Just in case, if you also want to consider commission, you can adjust the back odds like this:
1 + (odds - 1) * (1 - commission).
You will find out the real odds you get after commission.

Thank you! You are completely correct, it was a setting in excel that was wrong! Could you help me change the formula to get the backodds also?
 Logged
ppintaluba
Totally Pro

Karma: 37
Posts: 645

« Reply #3 on: December 14, 2014, 03:22:45 PM »
0

The formula is correct, and there's no need to be a math pro
If it shows a % it may be a formatting problem in the excel.
Just select the cell with the formula, right click the mouse and choose format cells and then choose category "number" and select 3 or 4 decimal places.
Just in case, if you also want to consider commission, you can adjust the back odds like this:
1 + (odds - 1) * (1 - commission).
You will find out the real odds you get after commission.

Thank you! You are completely correct, it was a setting in excel that was wrong! Could you help me change the formula to get the backodds also?

What's the question? This formula is to get the back odds.
 Logged

Smart Bet Tracker
www.smartbettracker.com
Kynao
Gaining experience

Karma: 0
Posts: 9

« Reply #4 on: July 25, 2018, 08:16:25 AM »
0

Would you have the same formula for Lay odd ?

With Cv being the odd value to be found : Cv = C - ( C -1 ) * com

Does it look valid ?
 Logged
ppintaluba
Totally Pro

Karma: 37
Posts: 645

« Reply #5 on: July 27, 2018, 02:33:35 AM »
0

If Lay is the lay odd (such as 2.5) and Com is the commission (such 0.05):

RealLay = (Lay - Com) / (1 - Com)
 Logged

Smart Bet Tracker
www.smartbettracker.com
Kynao
Gaining experience

Karma: 0
Posts: 9

« Reply #6 on: July 27, 2018, 08:42:35 AM »
0

Thank you.
I try to compare with others formulas given on several websites and as they're different so i'm a little confused

For example, i have been given this formula for back odd : Cv = C - ( C -1 ) * com
While for Lay odd, for example here http://www.geekstoy.com/forum/showthread.php?7083-Lay-odds-formula seems different than yours.

To simplify things, i will forget all other formulas and concentrate on yours, so you have :

- RealBack odd = 1 + (Back odd - 1) * (1 - Com).
- RealLay odd = (Lay odd - Com) / (1 - Com).

Let's say we have :
- commission is 0.05,
- back odd value is 1.7   and back stake is 2€
- lay odd value is 1.5 and lay stake is 2.27€

Without commission, if players wins, my profit with the back will be :
back odd * back stake - back stake = 1.7 * 2 - 2 = 1.4€
while on the lay bet i lose lay odd * lay stake - lay stake = 1.5 * 2.27 - 2.27 = 1.1135€

Without commission, if players looses, my profit with the lay will be 2.27€ while on the back bet i lose 2€

Good point here is we have profit whatever the player win or loose.
Now what if we continue the example with the comissions ?

- RealBack odd = 1 + (1.7 - 1) * (1 - 0.05) = 1.665

- RealLay odd = (1.5 - 0.05) / (1 - 0.05) = 0.07895. This one seems wrong

Could you continue with these (back and lay bets values examples) up to the profit (commission taken into account) based on your formulas ?
 « Last Edit: July 27, 2018, 08:53:13 AM by Kynao » Logged
ppintaluba
Totally Pro

Karma: 37
Posts: 645

« Reply #7 on: July 27, 2018, 06:41:24 PM »
0

Quote
While for Lay odd, for example here http://www.geekstoy.com/forum/showthread.php?7083-Lay-odds-formula seems different than yours.

This formula is the same I posted, but this site is using percentage commissions (such as 5), instead of 0.05. That´s why they divide commission by 100 in their formula

Quote
- RealBack odd = 1 + (1.7 - 1) * (1 - 0.05) = 1.665
- RealLay odd = (1.5 - 0.05) / (1 - 0.05) = 0.07895. This one seems wrong

It is in fact wrong: (1.5 - 0.05) / (1 - 0.05) = 1.5263 (at least in my country )

 Logged

Smart Bet Tracker
www.smartbettracker.com
Kynao
Gaining experience

Karma: 0
Posts: 9

« Reply #8 on: July 27, 2018, 07:13:18 PM »
0

Yes yes    Beer are stronger in my county

Coming back to the subject, would you complete the example ?

How is it used ? This means if the player wins, and if i back with 2€ with 1.7 as odd, my profit will be  2 * 1.665 - 2 = 1.33€ (instead of  1.7 * 2 - 2 = 1.4€)
Then i have to minus lay loss = 1.52632 * 2.27 - 2.27 = 1.19474€ (instead of 1.5 * 2.27 - 2.27 = 1.1135€)
So my final profit will be 1.33€ -  1.19474€ = 0.13526(instead of the previous calculated 2 = 1.4€ - 1.1135€ = 0.2865€)

Am i correct this time or i drink another beer ?
 Logged
ppintaluba
Totally Pro

Karma: 37
Posts: 645

« Reply #9 on: July 27, 2018, 07:23:03 PM »
0

But are you backing in the exchange with 5% commission? Or are you backing in a bookmaker without commission, and laying in the exchange with 5% commission?. If you have commission in the back bet, you should have included it your first example, so profit was not 1.4. It was 1.33 from the start.

2€ @1.7 (less commission): 2 * 1.7 - 2 (less commission) = 1.4 (less commission) = 1.33
2€ @1.665: 2 * 1.665 - 2 = 1.33
 Logged

Smart Bet Tracker
www.smartbettracker.com
Kynao
Gaining experience

Karma: 0
Posts: 9

« Reply #10 on: July 27, 2018, 07:33:33 PM »
0

I were supposing to do back and lay in a betting exchange with a commission on both moves.

I feel what you just said is what is aid previously or i miss something ?
ie ie based on my understanding that :

1. the betting exchange shows odds which does not include commissions so we have to calculate them if we don't want the balance account shows us some surprises.
2. I modify the odds presented by the betting exchange with the help of your formulas to obtain "virtual odds" from which i can do my usuals calculations (which we did in our last 2 messages as i feel we said the same thing)
 Logged
Kynao
Gaining experience

Karma: 0
Posts: 9

« Reply #11 on: July 27, 2018, 07:42:25 PM »
0

I think i will take a beer again
As on this commission subject, it seems hey are calculated differently here if we take the example of 2 betting exchanges : SMarket and Matchbook

So, How to calculate commission on a betting exchange ?

https://help.smarkets.com/hc/en-gb/articles/115003370169-How-to-calculate-commission-on-a-betting-exchange

In short Commission charged = ((stake * odds) - stake) * commission rate

My understanding if my beer is not too strong, is :
what you should have in your pocket * commission rate.

https://www.matchbook.com/page/getting_started/howcommissionrateiscalculated/

In short : stake odds * odds * commissions

This is not the same thing.
 Logged
ppintaluba
Totally Pro

Karma: 37
Posts: 645

« Reply #12 on: July 27, 2018, 08:18:08 PM »
0

Commissions in Matchbook are different!. This is just for Betfair, Smarkets, Betdaq, etc.

Back bet with commission, both formulas
2€ @1.7 (less commission): 2 * 1.7 - 2 (less commission) = 1.4 (less commission) = 1.33
2€ @1.665: 2 * 1.665 - 2 = 1.33
It's clearly the same.

But I don't know where did you get the lay stake and the lay formula. In generally I do the math using liability and back odds equivalent for the lay bet.

Lay bet equation profit: liability * back odds eq - liability
In your case: Lay odds is 1.5. So back odds eq = 3.
And the correct liability should be 1.15

Lay bet with commission (using back odds equivalent), both formulas
1.15€ @1.5(lay) (less comm) = 1.15€ @3 = 1.15 * 3 - 1.15 (less comm)= 3.45 - 1.15 (less comm) = 2.30 (less comm) = 2.30 - 0.115 = 2.185
1.15€ @1.5263(lay) = 1.15€ @2.9 = 1.15 * 2.9 - 1.15 = 3.335 - 1.15 = 2.185
It's also the same.

2 @1.7 (back): profit => 1.33
1.15 (liability) @1.5 (lay): profit => 2.185

Arbitrage profit:
1.33 - 1.15 (if you win back bet) = 0.18
2.185 - 2 = 0.185 (if you win the lay bet)

I know it looks complicated, but I always do the math using back bets (converting lay odds to back odds equivalent and using the back bet formulas)
 Logged

Smart Bet Tracker
www.smartbettracker.com
Kynao
Gaining experience

Karma: 0
Posts: 9

« Reply #13 on: July 27, 2018, 08:40:09 PM »
0

ok, so the formulas we are talking about don't work on matchbook, noted.

>But I don't know where did you get the lay stake and the lay formula.

The lay stake, i just gave is an example, so what not?
About the lay formula, i'm confused, you were the one to give it to me in this thread RealLay = (Lay - Com) / (1 - Com), i'm just using it.

>Lay bet equation profit: liability * back odds eq - liability. In your case: Lay odds is 1.5. So back odds eq = 3. And the correct liability should be 1.15

I'm sorry, i'm getting more confused, what's the point ?

> Lay bet with commission (using back odds equivalent), both formulas
>1.15€ @1.5(lay) (less comm) = 1.15€ @3 = 1.15 * 3 - 1.15 (less comm)= 3.45 - 1.15 (less comm) = 2.30 (less comm) = 2.30 - 0.115 = 2.185
>1.15€ @1.5263(lay) = 1.15€ @2.9 = 1.15 * 2.9 - 1.15 = 3.335 - 1.15 = 2.185

Ok, i'm lost  , would have been easier for me to rely on the previous example than starting on a new one.

At the end, whatever the kind of approach, i rely on formulas giving me the opposite stake amount i should look for,
=> ie for given lay and back odd and stake of one side, i calculate the stake for the other side so for the example of a back / lay calculation, i have a formula taking into account a ponderation coefficient (allowing you to define more a side against the other) but this formula does not take into account commissions.

This is the reason why at the end, instead of commissions formulas based on odd, i would prefer simpler commission formulas based on profit.
 « Last Edit: July 27, 2018, 08:41:45 PM by Kynao » Logged
ppintaluba
Totally Pro

Karma: 37
Posts: 645

« Reply #14 on: July 27, 2018, 08:55:07 PM »
0

OK. My confusion is because I don´t know this formula in your first example:

Quote
while on the lay bet i lose lay odd * lay stake - lay stake = 1.5 * 2.27 - 2.27 = 1.1135€
Where did you get this? You cannot use lay odds as if they where back odds and multiply them by a stake. I think this is the whole problem.

You must convert lay odds to back odds equivalent, and you must use a liability (given that 1.5 lay odds is equivalent to 3 back odds, the right liability should be 1.15 to have equal profit in both cases).

This is what I used in my previous post.
 Logged

Smart Bet Tracker
www.smartbettracker.com
 Pages: [1] 2

Related Topics

Subject / Started by Replies Last post
5 Replies
9190 Views
August 03, 2011, 01:28:09 PM
by arbusers
3 Replies
4270 Views
October 24, 2011, 08:13:22 PM
by Dropkick
7 Replies
5335 Views
November 21, 2011, 09:40:21 AM
by MUCHBET
9 Replies
11849 Views
April 13, 2012, 05:38:43 AM
by MUCHBET
1 Replies
8759 Views
September 09, 2012, 12:59:59 PM
by pol22
3 Replies
26916 Views
January 18, 2014, 06:56:44 PM
by peleus
1 Replies
3030 Views
August 29, 2013, 09:24:06 PM
by arbusers
3 Replies
2991 Views
April 22, 2014, 07:13:05 PM
by ranrom
4 Replies
4248 Views
September 26, 2014, 09:44:55 PM
by RaidTheBookie.com
10 Replies
3655 Views
September 13, 2014, 10:35:39 AM
by Thordin
52 Replies
17192 Views
March 21, 2016, 02:54:52 PM
by arber_PL
1 Replies
6757 Views
October 05, 2014, 08:21:41 AM
by eltrien
2 Replies
2499 Views
January 15, 2015, 09:19:11 PM
by dwaynnyt
1 Replies
2595 Views
February 01, 2015, 08:31:12 PM
by arbusers
5 Replies
6357 Views
March 03, 2016, 09:52:00 AM
by CharlieSheen99
7 Replies
6546 Views
March 05, 2016, 10:23:36 AM
by Thordin
5 Replies
3692 Views
January 29, 2016, 12:10:47 AM
by Saloman
34 Replies
9717 Views
July 15, 2016, 03:29:43 PM
by Opaque
2 Replies
2412 Views
May 07, 2016, 05:12:14 PM
by AceJack
0 Replies
2124 Views
February 25, 2016, 02:27:53 AM
by bingo
2 Replies
3453 Views
May 12, 2016, 06:08:24 PM
by freaked
16 Replies
4119 Views
July 10, 2016, 07:39:00 AM
by AceJack
10 Replies
5053 Views
September 25, 2016, 03:41:23 PM
by AceJack
3 Replies
2360 Views
December 15, 2016, 11:30:12 PM
by Bubbles
1 Replies
2085 Views
June 29, 2018, 12:49:03 PM
by christianj
0 Replies
1165 Views
September 19, 2018, 03:03:30 PM
by neopas
2 Replies
2000 Views
February 01, 2019, 09:35:23 AM
by WGFP
1 Replies
1146 Views
February 16, 2020, 10:03:02 AM
by kustef
29 Replies
4102 Views
July 23, 2021, 09:25:49 AM
by The 1xBet Support
2 Replies
748 Views
July 03, 2021, 04:35:05 PM
by Bdawg087
0 Replies
349 Views
June 11, 2021, 01:30:48 PM
by GStyle
2 Replies
452 Views
June 27, 2021, 03:39:30 PM
by Rampampam
2 Replies
436 Views
July 17, 2021, 10:32:43 PM
by arb12