The Time Decay Calculators are mathematical models of the in-play odds. It is important to understand that mathematics can’t predict how teams will play. So, you might be wondering how useful these calculators are. 

At any minute of the match, the difference between the Market Odds and the Time Decay Calculator reflects how the teams are playing. 

 For example, if the 0-0 odds on the calculator are shorter (eg 17) than the Market Odds (eg 20), this means that the match is predicted to have more goal scoring opportunities than initially expected. This could be because the teams are playing better or more aggressively than expected. Conversely, if 0-0 odds on the calculator are longer (eg 20) than the Market Odds (eg 17), this means that the match is likely to have less goal scoring opportunities than expected. This could be because there is the teams are playing defensively or because the game is scrappy.

1. Go to Betting Exchange and Input 5 Odds into the Time Decay Calculator
The first step is to input 5 pre-match odds into the calculator. These odds should be taken from the betting exchange. 

These include the 3 match odds (Home/Draw/Away) and the odds for 0-0 at full-time and 0-0 at half-time.
The odds for 0-0 at half-time are usually in a weak market. On the betting exchange, you can find these odds the correct score at half-time market or the over/under 0-5 goals at half-time market. Even if there are gaps in the odds, you can estimate the odds that will lie between the gap. 

You should note down these odds pre-match, as close to the start of the match as possible.  Once you have input these odds, you will see that a Time Decay Graph for the Match Odds will appear.

2. Goals Data
If you scroll down, you will see that you can input up to 6 goals, based on which side scored and the times that the goals were scored. 

When you input the goal information, you will see that the Time Decay chart will show how the mathematical odds change following a goal. 

The Time Decay match odds will usually be different from the betting exchange odds, following a goal.
I explain the reasons in detail for this in my book (which is soon to be published). The mathematical odds will often be different from the betting exchange odds after a goal because the teams’ strategies will change. This is especially the case if an underdog scores the first goal, as some underdogs become completely defensive in this situation. Even favourites can become more defensive after they have scored a goal.

3. In-Play Analyser
The in-play analyser can tell you whether your bet/trade is winning or losing in-play, relative to the mathematical (Time Decay) odds. For example, if you have bet on 0-0 at the start of a match and no goals are scored by the 20th minute, your bet will probably be winning due to the time decay. 

There are 3 possible scenarios. 

Firstly, your bet may be winning purely due to the time decay. In this case, the betting exchange odds and the mathematical odds will be the same.

Secondly, your bet may be winning more than expected due to the time decay. In this case, the performance the teams may be scrappy or more defensive than the market expected pre-match. 

Thirdly, your bet may be winning because of the time decay, but not winning as much as expected. In this case, there may be more end to end action than expected or one team could be dominating the action.

The in-play analyser has 4 inputs: the Market, Back/Lay, Exchange Odds and Minute. 

1. The Market is self-explanatory (ie whether you have traded on any of the correct score markets).
2. Back/Lay represents whether you are doing the analysis from a backer’s or layer’s perspective.
3. Exchange Odds are the odds on the betting exchange at the time you are doing the analysis.
4. Minute is the time into the match that you are doing the analysis. 

Once you have input the above information, you will see that a horizontal green or red line appears on the chart. If the line is green, it means that your bet is equal to or better than the result expected at this minute of the game. If the line is red, it means that your bet is worse than the result expected at this minute of the game.

On the In-Play analyser, you will see the mathematical odds (“Maths Odds”) and the percent difference between the mathematical odds and the betting exchange odds.

Matches are Longer than 90 minutes
There are 3 points on the chart where the maths is most accurate. This is at the start of the match (0 minutes), half-time (45 minutes) and full-time (90 minutes). 

The calculator can’t take into account time added on due to injuries etc. Regardless of how many minutes are added on, half-time is always represented by 45 minutes and full-time is always represented by 90 minutes. At any other time of the match, there will be an element of estimation, unless you are watching the match with a stopwatch and counting the time to be added on while the match is in-play. I don’t expect many people will do this and I don’t do this myself.