How to Convert HP to MPH [HP to MPH Chart] | (2024)

While no specific formula for the conversion of engine power (HP) to top speed (mph) exists, you can expect the following mph/HP ballpark figures in these vehicle categories:

• Riding movers: 0.2-0.3 mph/HP
• F1 cars: 0.2 mph/HP
• Jet skis: 0.3-0.8 mph/HP
• Large outboards: 0.4-0.6 mph/HP
• Snowmobiles: 0.6-0.8 mph/HP
• Small outboards: 0.8-1.3 mph/HP
• Average cars: 0.6-1.1 mph/HP
• Large motorcycles: 0.8-1.6 mph/HP
• UTVs: 1-1.2 mph/HP
• ATVs: 1.5-5 mph/HP
• Small motorcycles: 3-10 mph/HP

If you wonder where these numbers came from and how you can convert engine HP to top speed mph, this post is for you.

We at PowerSportsGuide have compiled all you need to know under one roof!

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How to Convert HP to MPH

Converting engine power (HP) into top speed (mph) – does this make any sense?

Many say it’s impossible since no two vehicles out there are the same.

For example, you can expect different top speed figures on a vessel than on a wheeled vehicle, even if the same type of engine powers them.

Because of this, there’s no specific formula for the conversion of engine HP to mph.

However, when you compare vehicles with different engines within a given category, you can see a noticeable relationship between engine power and speed.

To show some examples, we’ve paired the HP and top speed figures of some powersport vehicles:

ATVs:

• (125cc) 6-8 HP = 25-40 mph (4-5 mph/HP)
• (250cc) 15-35 HP = 35-45 mph (1.3-2.3 mph/HP)
• (500cc) 30-40 HP = 50-60 mph (1.5-1.7 mph/HP)
• (600cc) 40-45 HP = 60-65 mph (1.4-1.5 mph/HP)
• (700cc) 40-50 HP = 70-75 mph (1.5-1.8 mph/HP)

Motorcycles:

• (50cc) 3-9 HP = 35-50 mph (5-10 mph/HP)
• (125cc) 10-15 HP = 65-70 mph (5-6 mph/HP)
• (200cc) 15-25 HP = 65-90 mph (3.6-4.3 mph/HP)
• (350cc) 35-45 HP = 100-120 mph (2.7-3 mph/HP)
• (500cc) 45-60 HP = 100-130 mph (2-2.2 mph/HP)
• (600cc) 55-130 HP = 100-165 mph (1.3-1.6 mph/HP)
• (1000cc) 80-220 HP = 100-170 mph (0.8-1.3 mph/HP)

As one may expect, the larger HP ratings ensure higher top speed figures within a certain category. (But interestingly, smaller engines provide much better mph/HP ratios.)

Are you wondering if this holds true within each vehicle category? And how do different vehicle categories relate to one another?

Let’s drill into the details and discuss these questions in detail!

How Fast is 1 Horsepower in MPH?

“How fast is one HP in MPH?”

This question seems absurd at first glance since the features of different types of vehicles and vessels vary widely.

But we at PowerSportsGuide have conducted comprehensive research and compiled the mph/HP ratios of many different vehicles under one roof.

Based on our research, 1 HP translates to about 0.2-2 mph if we are discussing average vehicles and vessels.

More precisely, 1 HP equals 0.3-1.3 mph for vessels like smaller boats and jet skis, 0.6-1.2 mph for average cars and UTVs, 0.8-1.6 mph for most heavy and middleweight motorcycles, and 3-10 mph for lightweight motorcycles.

For your convenience we’ve listed some the “HP to mph conversion rates” for some common vehicle and vessel categories:

• Riding movers: 17-24 HP = 4-6 mph (0.2-0.3 mph/HP)
• F1 cars: 900-1100 HP = 220-250 mph (0.2 mph/HP)
• Jet skis: 60-300 HP = 40-70 mph (0.3-0.8 mph/HP)
• Large outboards: 50-150 HP = 35-55 mph (0.4-0.6 mph/HP)
• Snowmobiles: 120-210 HP = 90-120 mph (0.6-0.8 mph/HP)
• Small outboards: 20-25 HP = 15-30 mph (0.8-1.3 mph/HP)
• Average cars: 65-300 HP = 70-170 mph (0.6-1.1 mph/HP)
• Large motorcycles: 55-220 HP = 90-170 mph (0.8-1.6 mph/HP)
• UTVs: 50-170 HP = 50-85 mph (1-1.2 mph/HP)
• ATVs: 6-50 HP = 25-75 HP (1.5-5 mph/HP)
• Small motorcycles: 3-45 HP = 30-120 mph (3-10 mph/HP)

It’s no surprise that the slowest vehicles are utility machines like riding lawnmowers.

The engines of these machines generate 17-24 HP, which ensures a top speed of 4-6 mph. Dividing these numbers will result in an mph/HP ratio of 0.2-0.3; in other words, a riding lawnmower produces about 0.2-0.3 mph for one horsepower.

Surprisingly, you can find the mph/HP ratings of extremely fast F1 cars in the same ballpark.

How is this possible?

Although these high-performance cars can hit a top speed of 220-250 mph, they are powered by 900-1100 HP engines. We can see that 1 HP can only produce 0.2 mph in an F1 car if we do the math.

Regarding vessels, smaller (20-25 HP) outboards can propel boats up to 15-30 mph resulting in a mph/HP ratio of 0.8-1.3. In contrast, larger outboards typically only provide 0.4-0.6 mph for 1 HP. Sure, it strongly depends on the boat’s type, weight, and features.

Jet skis are known for their amazing performance; most of them are powered by 60-300 HP engines. But due to the water’s high resistance, they top out at 40-70 mph. Finally, a jet ski engine can provide 0.3-0.8 mph for one horsepower.

You can expect to get 0.6-0.8 mph from one horsepower on 600-1000cc snowmobiles since the top speed of these 120-210 HP machines ranges from 90 mph up to 120 mph.

There’s no question that one of the most exciting categories is motorcycles.

Thanks to their high-performance engines, middleweight, and heavy motorcycles have 55-200 HP, translating to a top speed of 90-170 mph (0.8-1.6 mph/HP).

On the other end of the spectrum, you can find lightweight motorcycles. These 300cc-350cc machines give you about 3 mph for every horsepower, while the 125-200cc category vehicle produces 3.5-5 mph per 1 HP.

The best mph/HP ratios are claimed by the tiny 50cc motorcycles. These bikes generate 3-9 HP and can go as fast as 30-50 mph, which results in an outstanding mph/HP ratio of 5-10!

HP to MPH Conversion Chart

Let’s compare some vehicle categories by their mph/HP ratios in one chart!

Disclaimer: Please consider this list a collection of some hard numbers, posted only for information purposes. You will likely find some machines with better or poorer mph/HP figures if you do your research. But it’s safe to say that most stock vehicles fall into these ranges.

Conclusion

There’s no magic formula for converting engine HP to mph, as the top speed of different vehicles depends on countless factors like their type, design, and engine features.

For example, a 3 HP motorcycle can go as fast as 30 mph, which means you get 10 mph out of every horsepower. In contrast, a 1000cc, 80-220 HP motorcycle tops out at 100-170 mph, providing only 0.8-1.3 per HP.

Another example of interest is comparing GP motorcycles to small outboards. A boat with a 25 HP (500cc) outboard can only reach 20-30 mph, while the same displacement racing engine can produce 200-240 HP and propel a GP motorcycle to 220-250 mph.

Surprisingly, both machines can produce about 1 mph per 1 HP!

But even if there’s no strict correlation between HP and mph figures, we can calculate a “conversion number” for the various vehicle categories.

Based on our research, 1 HP equals 0.2-2 mph for most cars and many powersport vehicles. ATVs and lightweight motorcycles stand out from the crowd with their HP/cc ratios of 1.5-10.

(Please consider these figures as hard numbers that can be applied to many stock vehicles and vessels.)