Fully dynamic calculator: How World Rugby ranking points are exchanged between competing nations
Overview
“Rankings are rubbish,” is a sentiment often proffered by rugby union fans. Of course, some kind of mathematical calculation has to be used to determine where nations sit relative to each other. And where there's maths, confusion can quickly follow.
This webpage is designed to help demystify those ranking calculations. They don't change on a whim, but according to a fixed algorithm. Tweak the sliders for Nation A and Nation B below, and the page updates in real time, showing exactly how each calculation is made.
Step 1 · Determine the rating gap
Step 2 · Turn the gap into an adjustment factor
This takes the capped gap (which maxes out at ±10) and scales it down to ±1 — the same scale as the win/draw/loss values used in the next step, so the gap can nudge them up or down directly.
Step 3 · Calculate the base outcomes
Step 4 · Apply margin and World Cup weighting
The base exchange we've calculated can then be impacted in 2 further ways. World Rugby determined that the base exchange applies to results where the win margin was by 15 points or fewer. Beyond that margin, the exchanges are multiplied by 1.5.
The second way, is that within a Rugby World Cup tournament, all the figures calculated in the previous paragraph get doubled again.
Outcome scenarios
Normal international matches
| Scenario | Nation A change | Nation B change | Nation A new points | Nation B new points | New difference |
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Rugby World Cup matches
| Scenario | Nation A change | Nation B change | Nation A new points | Nation B new points | New difference |
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