Bathmate Hydromax X30 vs X40:
Which Size Should You Actually Buy?
This is the most common question we receive about Bathmate. Get the size wrong and you waste your money — or worse, limit your results. Here’s the complete, honest answer based on exact measurements and real user data.
“Buy the X30 if your erect length is under 7 inches. Buy the X40 if your erect length is 7 inches or more, or if your erect girth is above average. When you’re genuinely unsure between the two — always choose the X40. A pump that’s slightly too large is always better than one that’s too small.”
Why Choosing the Right Size Actually Matters
Bathmate pumps work by creating a water-based vacuum around your shaft. The cylinder needs to be the right size for your anatomy to create the correct vacuum seal and pressure. If the cylinder is too small, you won’t be able to achieve full erection inside it and may experience discomfort or restricted blood flow. If it’s too large, the seal won’t form properly and you lose suction — producing significantly weaker results per session.
This is why Bathmate offers multiple sizes — and why getting the choice right before you spend $119–$149 is worth five minutes of reading.
The Size Guide — X30 or X40?
Use this tool to find your model in 30 seconds:
Full Specification Comparison
Here is every measurable difference between the X30 and X40 side by side:
Who Should Buy Which Model
- Have an erect length under 7 inches
- Have average or below-average girth (under 5.5″ circumference)
- Are a first-time Bathmate buyer on a tighter budget
- Have been using the original Hercules and want to upgrade
- Want the most popular Bathmate model worldwide
- Have an erect length of 7 inches or more
- Have above-average girth (5.5″+ circumference)
- Are borderline between the two sizes
- Want to buy once and grow into the pump over time
- Have tried the X30 and feel it’s too tight
What About the X30 Wide Boy?
Bathmate also offers the Hydromax X30 Wide Boy — a model that combines the cylinder length of the X30 with the wider internal diameter of the X40. It’s priced at approximately $179 and designed specifically for men who are within the X30 length range but have above-average girth.
If you measure as follows, the Wide Boy is your model:
Erect length: Under 7 inches — but — Erect girth: Over 5.5 inches circumference (around 1.75 inches diameter)
The Wide Boy sits between the X30 and X40 in price and fills the gap for men who found the standard X30 too tight laterally but don’t need the extra length capacity of the X40.
X30 Pros & Cons
- Bathmate’s best-selling model worldwide
- $30 cheaper than the X40
- Perfect fit for average anatomy
- Easier seal for most men
- Same 35% suction power as X40
- Too small for men over 7 inches erect
- May feel tight for men with above-average girth
- Less room to grow into over 12+ months of use
X40 Pros & Cons
- Right size for above-average anatomy
- More room to grow into over time
- Better long-term investment if you’re borderline
- Wider internal diameter = more comfortable for broader girth
- Same 60-day guarantee as X30
- $30 more expensive than X30
- Harder to form a seal if you’re significantly smaller than the max size
- Unnecessary if your erect length is clearly under 6.5 inches
The 3 Most Common Sizing Mistakes
Mistake 1 — Measuring Flaccid Instead of Erect
Your pump size is determined by your erect measurements only. Flaccid measurements have no bearing on which model you should buy. Many men measure flaccid, underestimate their size, and buy an X30 when they should have bought an X40. Always take your measurements at full erection.
Mistake 2 — Choosing Too Small to Save $30
The $30 price difference between X30 and X40 is not worth choosing the wrong size. Using a pump that’s too small limits your results, reduces comfort, and may require you to buy again anyway. If you’re unsure, the X40 is always the safer investment.
Mistake 3 — Ignoring Girth When Choosing Length
Many men focus only on length when selecting a model and ignore girth entirely. If you have above-average girth even with a length that technically fits the X30, the X40 or Wide Boy will produce significantly better results because you’ll achieve a more effective vacuum seal.
When Should You Upgrade?
If you’ve been using the X30 for 6+ months and notice your penis touching the end of the cylinder when fully erect — it’s time to upgrade to the X40. This is a sign your sessions have been effective and you’ve outgrown the cylinder length. Continuing with a cylinder that’s too small at that point reduces the effectiveness of every subsequent session.
Similarly, if you started with the X30 and consistently feel your girth pressing uncomfortably against the sides — the Wide Boy or X40 is your upgrade path.
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Buy Bathmate X30 at Official Store → Buy Bathmate X40 at Official Store →
Frequently Asked Questions
The X30 and X40 are the same pump in different cylinder sizes. The X30 has an internal diameter of 2.25 inches and suits men up to 7 inches erect. The X40 has a wider internal diameter of 2.45 inches and is designed for men over 7 inches in length or with above-average girth. Both deliver the same 35% more suction power than the original Hercules and include the same locking valve and measurement guide.
Buy the X30 if your erect length is clearly under 7 inches and your girth is average. Buy the X40 if your erect length is 7 inches or more, your girth is above average (5.5 inches circumference or more), or you’re genuinely uncertain between the two. When in doubt, always choose the larger size — a pump that’s slightly too large is always preferable to one that’s too small.
Yes. Using an X40 when you are currently in the X30 size range is perfectly acceptable and gives you room to grow into the pump over time. You may find it slightly harder to form a perfect seal initially, but this improves with technique. Bathmate’s customer support consistently advises men to choose slightly larger over slightly smaller when borderline.
If your measurements put you clearly in the X40 range, yes — the $30 difference is irrelevant compared to the cost of buying the wrong size. If your measurements clearly put you in the X30 range, save the $30. The only situation where the X40’s extra cost is questionable is if your erect length is well under 6.5 inches and your girth is average.
The Hydromax X30 Wide Boy combines the length capacity of the X30 with the wider internal diameter of the X40 cylinder. It costs approximately $179 and is designed for men whose erect length is under 7 inches but whose erect girth is above average (over 5.5 inches circumference). If you find the standard X30 too tight laterally but don’t need the X40’s extra length, the Wide Boy is your answer.
Upgrade when you notice your penis touching the end of the X30 cylinder when fully erect inside the pump. This typically happens after 6–12 months of consistent use for men who started in the X30 range. Continuing with a cylinder that’s too short at that point reduces session effectiveness significantly.