Skip to content

How is cruise ship speed measured, and how fast is a knot in miles per hour?

July 12, 2022
5 min read
This post contains references to products from one or more of our advertisers. We may receive compensation when you click on links to those products. Terms apply to the offers listed on this page. For an explanation of our Advertising Policy, visit this page.

Have you ever wondered how cruise ship speed is measured? Ships aren't the fastest method of transportation, but that doesn't mean it's not fun to calculate your speed when you're sailing. Unlike land travel, ship speed is not measured in miles per hour.

Here, I'll cover how cruise ship speed is measured, how to calculate your ship's speed in miles per hour and some considerations that could affect how fast you're going.

For cruise news, reviews and tips, sign up for TPG's cruise newsletter.

What is a knot in nautical terms?

Sailors in the 17th century used ropes with knots to measure ship speed. (Photo by Westend61/Getty Images)

A knot is the nautical measure of speed used by cruise ships and other maritime vessels. One knot represents 1 nautical mile per hour.

But "knot" isn't simply a misspelled nickname for "naut" (as in nautical mile). Its origins are far more literal, according to the United States' National Ocean Service.

In the 17th century, ship crews measured vessel speed by tossing a rope with several evenly spaced knots and a triangular-shaped piece of wood into the water. As the ship moved, currents created resistance against the wood, causing more rope to be pulled into the water over a specified period of time. When time was up, crew members would pull the rope in and count the knots.

In short, the number of knots pulled out into the water over a specific period of time translated into the speed of the vessel's travel.

How fast is a knot in miles per hour?

When you convert 1 knot to miles per hour, it works out to 1.15 standard miles per hour for every nautical mile per hour. That's knot speed. So, although land-based miles per hour are just slightly faster than knots, for general purposes, it's a close comparison. For example, if your ship is sailing 20 knots, it's sailing roughly 23 mph.

How fast do cruise ships go?

Cunard Line's flagship, Queen Mary 2. (Photo by Angela Weiss/AFP/Getty Images)

What is the maximum speed of a cruise ship? The maximum speed for most modern vessels is about 30 knots or 34.5 mph, but just because they can glide along that fast doesn't mean they actually do, or at least not all the time.

Sign up for our daily newsletter

Officers on the bridge will adjust speed to account for weather and ocean conditions — rough seas and high winds mean slower speeds — and port arrival times. Early arrival into port can come with extra fees that cruise lines are loath to incur, which usually means they prefer to take their time by slowing their speed.

What is the average cruise ship speed?

Cruise ship average speed is affected by lots of outside forces, as mentioned above. In relatively calm conditions, the average present-day vessel travels about 20 knots or 23 mph between ports of call.

What is the fastest cruise ship?

SS United States sits at a dock in Philadelphia. It is the fastest passenger ship on record. (Photo by dovate/Getty Images)

Currently, the fastest cruise ship that's operational is Cunard Line's Queen Mary 2, which often serves as an ocean liner to ferry people back and forth between the U.S. and the United Kingdom. Its maximum speed is 30 knots.

Cunard, which has operated historically fast vessels throughout the years, won the Blue Riband — a coveted prize for the ship to cross between the U.S. and Europe while maintaining the highest speed — 18 times. The last ship in the fleet to hold the unofficial award, which dates back to the 1800s, was Queen Mary, which is currently a floating hotel in Long Beach, California, near Los Angeles.

Queen Mary was dethroned as the winner in 1952 by SS United States, which was operated by rival United States Lines and made the crossing in just three days, 10 hours and 40 minutes at a speed of nearly 35.6 knots or almost 41 mph. (Its maximum speed was 39 knots or about 45 mph.)

Today, SS United States is docked in Philadelphia and maintained by a nonprofit conservancy that hopes to find investors to restore the languishing liner, which is now more than 70 years old. It might not be operational, but its previous accolades make it the fastest passenger vessel currently afloat.

Planning a cruise? Start with these stories:

Featured image by Getty Images
Editorial disclaimer: Opinions expressed here are the author’s alone, not those of any bank, credit card issuer, airline or hotel chain, and have not been reviewed, approved or otherwise endorsed by any of these entities.

Top offers from our partners

How we chose these cards

Our points-obsessed staff uses a plethora of credit cards on a daily basis. If anyone on our team wouldn’t recommend it to a friend or a family member, we wouldn’t recommend it on The Points Guy either. Our opinions are our own, and have not been reviewed, approved, or endorsed by our advertising partners.
See all best card offers

TPG featured card

Best for the well-traveled foodie
TPG Editor‘s Rating
Card Rating is based on the opinion of TPG‘s editors and is not influenced by the card issuer.
4 / 5
Go to review
Apply for American Express® Gold Card
at American Express's secure site

Rewards

3 - 4X points
4XEarn 4X Membership Rewards® Points at Restaurants, plus takeout and delivery in the U.S.
4XEarn 4X Membership Rewards® points at U.S. supermarkets (on up to $25,000 per calendar year in purchases, then 1X).
3XEarn 3X Membership Rewards® points on flights booked directly with airlines or on amextravel.com.

Intro offer

60,000 bonus points
Earn 60,000 Membership Rewards® points after you spend $4,000 on eligible purchases with your new Card within the first 6 months of Card Membership.

Annual Fee

$250

Recommended Credit

670-850
Excellent/Good
Credit ranges are a variation of FICO© Score 8, one of many types of credit scores lenders may use when considering your credit card application.

Why We Chose It

There's a lot to love about the Amex Gold card. It's been a fan favorite during the pandemic because of its fantastic rewards rate on restaurants (that includes takeout and delivery in the U.S.!) and U.S. supermarkets. If you're hitting the skies soon, you'll also earn bonus points on travel. Paired with up to $120 in Uber Cash (for U.S. Uber rides or Uber Eats orders) and up to $120 in annual dining statement credits at eligible partners, there's no reason that the foodie shouldn't add this card to their wallet. Enrollment required.

Pros

  • 4x on dining at restaurants and U.S. supermarkets (on the first $25,000 in purchases per calendar year; then 1x)
  • 3x on flights booked directly with the airline or with Amex Travel
  • Welcome bonus of 60,000 points after spending $4,000 in the first six months

Cons

  • Weak on travel outside of flights and everyday spending bonus categories
  • Not as useful for those living outside the U.S.
  • Some may have trouble using Uber/food credits
  • Few travel perks and protections
  • Earn 60,000 Membership Rewards® points after you spend $4,000 on eligible purchases with your new Card within the first 6 months of Card Membership.
  • Earn 4X Membership Rewards® Points at Restaurants, plus takeout and delivery in the U.S., and earn 4X Membership Rewards® points at U.S. supermarkets (on up to $25,000 per calendar year in purchases, then 1X).
  • Earn 3X Membership Rewards® points on flights booked directly with airlines or on amextravel.com.
  • $120 Uber Cash on Gold: Add your Gold Card to your Uber account and each month automatically get $10 in Uber Cash for Uber Eats orders or Uber rides in the U.S., totaling up to $120 per year.
  • $120 Dining Credit: Satisfy your cravings and earn up to $10 in statement credits monthly when you pay with the American Express® Gold Card at Grubhub, The Cheesecake Factory, Goldbelly, Wine.com, Milk Bar and select Shake Shack locations. Enrollment required.
  • Choose the color that suits your style. Gold or Rose Gold.
  • No Foreign Transaction Fees.
  • Annual Fee is $250.
  • Terms Apply.
  • See Rates & Fees
Apply for American Express® Gold Card
at American Express's secure site
Terms & restrictions apply. See rates & fees
Best for the well-traveled foodie
TPG Editor‘s Rating
Card Rating is based on the opinion of TPG‘s editors and is not influenced by the card issuer.
4 / 5
Go to review

Rewards Rate

4XEarn 4X Membership Rewards® Points at Restaurants, plus takeout and delivery in the U.S.
4XEarn 4X Membership Rewards® points at U.S. supermarkets (on up to $25,000 per calendar year in purchases, then 1X).
3XEarn 3X Membership Rewards® points on flights booked directly with airlines or on amextravel.com.
  • Intro Offer
    Earn 60,000 Membership Rewards® points after you spend $4,000 on eligible purchases with your new Card within the first 6 months of Card Membership.

    60,000 bonus points
  • Annual Fee

    $250
  • Recommended Credit
    Credit ranges are a variation of FICO© Score 8, one of many types of credit scores lenders may use when considering your credit card application.

    670-850
    Excellent/Good

Why We Chose It

There's a lot to love about the Amex Gold card. It's been a fan favorite during the pandemic because of its fantastic rewards rate on restaurants (that includes takeout and delivery in the U.S.!) and U.S. supermarkets. If you're hitting the skies soon, you'll also earn bonus points on travel. Paired with up to $120 in Uber Cash (for U.S. Uber rides or Uber Eats orders) and up to $120 in annual dining statement credits at eligible partners, there's no reason that the foodie shouldn't add this card to their wallet. Enrollment required.

Pros

  • 4x on dining at restaurants and U.S. supermarkets (on the first $25,000 in purchases per calendar year; then 1x)
  • 3x on flights booked directly with the airline or with Amex Travel
  • Welcome bonus of 60,000 points after spending $4,000 in the first six months

Cons

  • Weak on travel outside of flights and everyday spending bonus categories
  • Not as useful for those living outside the U.S.
  • Some may have trouble using Uber/food credits
  • Few travel perks and protections
  • Earn 60,000 Membership Rewards® points after you spend $4,000 on eligible purchases with your new Card within the first 6 months of Card Membership.
  • Earn 4X Membership Rewards® Points at Restaurants, plus takeout and delivery in the U.S., and earn 4X Membership Rewards® points at U.S. supermarkets (on up to $25,000 per calendar year in purchases, then 1X).
  • Earn 3X Membership Rewards® points on flights booked directly with airlines or on amextravel.com.
  • $120 Uber Cash on Gold: Add your Gold Card to your Uber account and each month automatically get $10 in Uber Cash for Uber Eats orders or Uber rides in the U.S., totaling up to $120 per year.
  • $120 Dining Credit: Satisfy your cravings and earn up to $10 in statement credits monthly when you pay with the American Express® Gold Card at Grubhub, The Cheesecake Factory, Goldbelly, Wine.com, Milk Bar and select Shake Shack locations. Enrollment required.
  • Choose the color that suits your style. Gold or Rose Gold.
  • No Foreign Transaction Fees.
  • Annual Fee is $250.
  • Terms Apply.
  • See Rates & Fees