The short version: a straight Olympic barbell is the do-everything bar that squats, benches, deadlifts, presses, and rows, so it belongs in your gym first and can anchor the whole thing on its own. An EZ bar - the short, wavy curl bar - only really improves one thing: it makes curls and triceps work easier on the wrists and elbows. It is a cheap, pleasant add-on for arm day, not a starting point. Buy the straight bar now; add the EZ bar later if your wrists ask for it. Here is the full comparison.
What an EZ bar is
An EZ bar - sometimes called an EZ curl bar - is a short barbell with a zig-zag bend in the middle of the shaft. That bend puts your hands on angled grips instead of a flat straight line, so your palms turn slightly toward each other rather than facing dead forward. It sounds like a small change, but it takes a lot of the twisting strain off your wrists and elbows during curls and lying triceps extensions (skullcrushers). If straight-bar curls have ever left your wrists or forearms achy, the EZ bar's angle is the fix.
An EZ bar is also lighter and shorter than a full barbell, which makes it easy to handle and easy to store in a corner. That compact size is part of the appeal for a home gym: it slips in without eating much floor space. But the same shape that makes it comfy for curls makes it useless for the big lifts. You cannot squat, bench, or deadlift properly with a bent, short bar - it will not sit right across your back or in your hands, and it is not built for that kind of load. The EZ bar does one narrow job very well and almost nothing else.
What a straight Olympic barbell is
A straight Olympic barbell is the long, rigid 7-foot bar you picture when you think of a barbell. It is the do-everything piece of a free-weight gym: you squat with it, bench press with it, deadlift with it, overhead press with it, and row with it. Those compound lifts are the ones that build the most strength and muscle for the time you put in, and they are exactly what a beginner should spend the bulk of their training on. One straight bar plus some plates is enough to run a complete, serious program for years.
Because it does so many jobs, the straight bar is the anchor the rest of a barbell gym is built around. Racks, benches, and plates all assume a full-length Olympic bar, so buying one puts you inside the ecosystem everything else fits into. If you are still deciding which straight bar to get, our guide to choosing a barbell walks through the specs that actually matter, and Olympic vs. standard barbell settles the sleeve-size question that decides which plates you can use. And yes - a straight bar curls arms perfectly well too. It is not as gentle on the wrists as an EZ bar, but it builds the same biceps.
Why the straight bar comes first
The logic is simple: buy the tool that does the most work first. A straight Olympic bar covers your entire lower body, your whole pressing and pulling routine, and your arms too. An EZ bar covers curls and a couple of triceps moves - real value, but a thin slice of a workout. If you can only own one bar for a while, the straight bar is not close to the right call, because it can be almost your entire gym while the EZ bar cannot be even a tenth of it.
There is also a progression argument. Getting stronger as a beginner comes mostly from the big lifts, and those need a straight bar. The arm-specific comfort an EZ bar provides only starts to matter once you are training consistently, adding volume, and maybe noticing your wrists grumble on heavy curls. That is a later chapter, not day one. Spend your first dollars on the bar that unlocks squats, presses, and deadlifts - the movements that make everything else worth doing - and you will build a real base of strength before the EZ bar ever becomes relevant. You can see where the straight bar sits among the pieces worth buying first on our best home gym equipment roundup.
Honest cons for both
The straight bar's downside for arm work is real: it forces your wrists into a flat, fully supinated position on curls, and some lifters find that nags at the wrists or the inner elbow over time, especially as the weight climbs. It is also the bigger up-front cost and the bulkier item to store. For most beginners neither of those is a dealbreaker - flat-wrist curls are fine for the vast majority of people, and the bar earns its space by doing five other jobs - but if you already know your wrists are cranky, that is worth knowing.
The EZ bar's downside is the flip side: it is a one-trick bar. Outside of curls and skullcrushers there is very little you can do with it, so if you buy it expecting a versatile tool you will be disappointed. It also cannot replace anything the straight bar does, which means an EZ bar as your only bar leaves your legs, back, and pressing untrained. It is a comfort upgrade layered on top of a real gym, not a substitute for one. Buy it for the right reason - easier arm day - and it delivers; buy it hoping it does more, and it will let you down.
The bottom line
For a first home gym, buy a straight Olympic barbell. It squats, benches, deadlifts, presses, and rows, so it can carry your entire program on its own and grow with you for years - and it curls your arms just fine in the meantime. An EZ bar is a genuinely nice add-on, but only for one job: making curls and triceps work easier on the wrists and elbows. Add it later, cheaply, once you are training regularly and want arm day to feel better on the joints.
Put another way: the straight bar is the gym, and the EZ bar is a small luxury you bolt on afterward. If curling with a straight bar feels fine - and for most beginners it does - you may never need the EZ bar at all. Start with the bar that does everything, load it with plates, and let the arm-day comfort piece wait its turn.