Unlike strikes landed per minute or takedown accuracy, there's no single official "durability number" published for UFC fighters. What you'll see broadcasters and analysts call a fighter's durability is almost always a homemade composite, built from a handful of raw numbers that each measure something slightly different — and each miss something important on their own.
There's no one formula
Ask five different analysts how they'd quantify a fighter's chin and you'll get five different answers, built from some mix of the same raw ingredients: significant strikes absorbed per minute, strike defense percentage, knockdowns received per 15 minutes, and the simple count of career losses that came by knockout or TKO. None of those is itself "durability" — each is a proxy for it, and proxies disagree with each other more often than you'd expect.
Some outlets have gone further and built proprietary scores that claim to measure "KO resistance" or similar by combining offensive power against defensive resilience into a single index. Those scores aren't built on a published, independently verified methodology, so they're worth treating as entertainment rather than analysis — a number with no visible formula behind it can't be checked, and can't be trusted the way a raw, countable stat like strikes absorbed can.
The building blocks, and what each one actually measures
Strikes absorbed per minute measures volume taken, not damage sustained — a fighter who eats a lot of jabs and a fighter who eats a lot of power shots can post the same number. Strike defense percentage measures how often strikes are avoided relative to how many were thrown at the fighter, which rewards footwork and head movement as much as a durable chin. Knockdowns received per 15 minutes is the closest thing to a direct damage signal, but it's a low-frequency event — most fighters go through long stretches of their careers without recording any, which makes the number noisy for anyone without a deep fight history. Career KO/TKO losses is the bluntest tool of all: it counts outcomes, not the punches that produced them, and it treats a one-punch knockout from an elite puncher the same as a cumulative battering over three rounds.
What composite "durability" misses
Opponent power varies enormously, and these raw counts don't adjust for it. Absorbing strikes from a leading knockout artist and absorbing the same number of strikes from a volume-based decision fighter are not the same experience for a chin, but the stat treats them identically.
Weight class changes what a "lot of strikes absorbed" even means. Heavier divisions see fewer total strikes thrown and a higher share of fight-ending power in each one, so a heavyweight's absorption numbers and a flyweight's aren't comparable on the same scale without adjusting for it.
Durability isn't static — it changes with age, and the stats lag behind the decline. A fighter's career-long absorption numbers can look fine for years right up until the fight where the chin visibly goes, because a handful of recent knockdowns get diluted by a much larger sample of earlier, cleaner fights. Age curves are a real pattern in the sport, and a composite built from career totals is slow to catch a fighter on the wrong side of one.
Cardio-based fades get misread as chin problems. A fighter who gets caught and finished in the third round because he's exhausted, not because he has a fragile chin, shows up in the data identically to a fighter who simply can't take a clean shot. The strikes-absorbed number doesn't know the difference between "hit too much" and "too tired to defend by the third round."
A single bad night isn't a trend, but it moves the raw numbers a lot. One brutal knockout loss can swing a fighter's lifetime knockdown rate and absorption average more than several ordinary, competitive decisions — which is the same distortion that shows up in average fight time: a stoppage ends the sample instantly, so it carries disproportionate weight in any average built from it.
How to actually use these numbers
Treat strikes absorbed, strike defense, knockdowns taken, and KO-loss count as four separate data points to read together, not four inputs to average into one score. A fighter who's high on absorption but low on knockdowns received is someone who eats volume but has a real chin underneath it. A fighter who's low on absorption but has a recent knockdown is someone who hasn't been tested much but didn't hold up the one time he was. Those are two very different fighters that a single blended "durability" number would describe almost identically.
The most reliable read still comes from watching recency and method together: a fighter's last three results, by method and round, tell you more about where his durability stands right now than a career-wide average ever will — because a chin that held up at 26 isn't guaranteed to hold up at 34, and the career-long stat doesn't know which fighter you're looking at.
The takeaway
"Durability number" sounds like a single, official stat, but it's really a stack of four imperfect proxies — strikes absorbed, strike defense, knockdowns taken, and KO losses — that analysts combine in whatever way they prefer, with no agreed-upon formula behind any of it. Read the raw numbers separately, weight recent fights more than career averages, and treat any single blended score claiming to measure a fighter's chin as a talking point, not a verified stat.