Guillermo
32,148 recorded births · active 1885–2025
Compare Guillermo →Living-age distribution
The median living Guillermo is 31. If you meet a Guillermo, there's about a 70% chance they're between 14 and 53 years old.
Popularity arc
Peak Guillermo: 1996. Down 55% from peak.
Projected: the dashed 10-year forecast (Holt damped-trend exponential smoothing, fit to recent years), with a shaded 95% interval.
Gender balance
Guillermo is almost always given to male babies — 99.7% male.
Rarity
Guillermo ranks #1,449 out of 105,966 names ever recorded by the SSA.
Geographic fingerprint
Guillermos are 2.7x more common in the West than the national average.
Predictive modeling
Three statistical models, all fit to Guillermo's own SSA history plus the historical behavior of every other name in the dataset.
Peak popularity prediction
Guillermo's modeled peak was #730 in 1994 — its trend isn't projected to beat that.
Projects the trend forward, then converts share into rank using this year's popularity distribution.
This forecasts Guillermo's share of births by fitting a damped-trend model to its last 125 years of data and projecting 10 years forward with a widening uncertainty band. Each projected share is then translated into a rank by comparing it against 2025's actual name-popularity distribution — so the model implicitly assumes the overall shape of that distribution doesn't shift much over the forecast window. Its trend is projected to stay below its historic best over the next 10 years, so the model treats 1994 as its peak. Milestone probabilities come from how much of each year's uncertainty band clears that milestone's rank, combined across years as if they were independent — which slightly overstates the odds for names sitting right at a threshold, since a good year is usually followed by another good year rather than an independent coin flip.Name life-cycle stage
A rule-based classifier over recent growth, momentum, and peak proximity.
Guillermo's popularity has been easing lower recently, though not sharply enough to call it a steep decline.
Popularity survival model
Once a name reaches a rank tier, how long does it typically stay there before falling out?
Built from a Kaplan-Meier survival curve: every historical run any name has ever had above this tier, with runs still ongoing today counted as still in progress rather than as an exit.Guillermo isn't currently in the Top 100 tier. Estimated chance of entering it in the forecast window: 0%.
If Guillermo enters Top 100, chance it's still there after:
Names that do enter Top 100 have historically stayed a median of ~19 years. Based on 668 historical Top 100 runs across every name in the dataset.