Calcs & Convertors

The Toolkit

Calcs & Convertors

These tools don’t predict anything. Paired with the xWin Engine’s probabilities, they’re what turns a view into a properly sized bet.

The same calculators we’ve used for years alongside the match maths, nothing new, just made public.

  • Convert a price
  • Strip the bookmaker’s margin
  • Check if a bet is actually worth the stake
  • Size a lay to lock in a position

Bring your own view of the match. These tools just make sure the numbers stack up.

Build your own predictions
Why this tool

This isn’t the model powering the rest of the site, but it’s the same maths, handed to you. Set your own expected goals for either side and see what probabilities that view implies.

1.70 1.20 0.0%
Home Win Draw Away Win
Over 1.5 0.0%
Over 2.5 0.0%
BTTS 0.0%
Score Probability Heatmap Grid
0 1 2 3 4 5
Probability & Odds convertor
Why this tool

Every odd or price is a probability wearing a different costume. We work in decimal because it converts straight back to a percentage with no extra steps but know people have their own preference. Enter any format below and the other three update to match.

Implied Probability Decimal Fractional American
90.9%1.101/10-1000
66.7%1.501/2-200
50.0%2.00Evens+100
33.3%3.002/1+200
20.0%5.004/1+400
10.0%10.009/1+900
Interactive Live Converter
Kelly Stake Sizing
Why this tool

Kelly staking sizes a bet by the edge you actually have, not a flat percentage of your bankroll. Bigger edge, bigger stake. No edge, no bet.

25.0%of full kelly
0.5% 25% 50% 75% 100%
Suggested Stake
£0.00
% of Bankroll
0.0%
Edge: +0.0% · Full Kelly: 0.0% of bankroll
Expected Value (EV)
Why this tool

Tells you whether a price is actually worth backing, given what you think the real probability is and not just whether you think it’ll win.

Expected Profit Edge +36.50% Proj. Stake Edge: +£3.65
True Odds (No bookie margin)
Why this tool

Every bookmaker price has their margin baked in. This strips it out and shows the market’s real, vig-free probability.

Market Overround: 5.7%
True Home (1) Odds: 2.11 (47.3%)
True Draw (X) Odds: 3.59 (27.8%)
True Away (2) Odds: 4.02 (24.9%)
Exchange Lay Stake Calculator
Why this tool

Sizes a lay bet on an exchange to lock in a result regardless of outcome — cash out a back bet or trade around a shifting price.

Ideal Lay Stake: £9.90
Lay Liability: £20.30
If Back Wins: £0.00
If Lay Wins: £0.00
Net Lock-In: £0.00