Fermi #75 · Question 1 of 3

How many days does a container ship take to sail from Shanghai to Rotterdam through the Suez Canal?

Fermi Answers Today
Answer

30 days

Napkin math

The sea route from Shanghai to Rotterdam covers about 20,000 kilometers, or half the distance around the world. A giant cargo ship may travel at 30 km/h, about the speed of a bike. That is roughly 700 kilometers per day.

Napkin math
Half way around the world≈ 20,000 km
30 km/h × 24 hours÷ 700 km a day
20,000 ÷ 700≈ 29 days

The published breakdown

Published breakdown
Shanghai to Rotterdam via Suez≈ 10,600 nautical miles
Non-stop at 16 knots≈ 27 days
Typical scheduled service, with a few port calls28 to 32 days
≈30 days

Source

Notteboom, Pallis & Rodrigue, Port Economics, Management and Policy: Routing Options between Shanghai, Rotterdam and New York

The other questions

Fermi's answer to this one is 30 days.

It was question 1 of 3 in Fermi #75, played on Friday, October 9, 2026. The napkin route chains a few rough guesses together and multiplies them out (first step: Half way around the world, ≈ 20,000 km).

What each guess would have scored

Fermi never marks a guess right or wrong. It divides the larger number by the smaller, so the score says how many times off you were. Lower is better.

Score windows

ScoreGuesses that earn it
1× (Spot On)Exactly 30 days
1.5× or better20 to 45 days
2× or better15 to 60 days
3× or better10 to 90 days
10× or better3 to 300 days

High and low misses count the same. Guessing half the answer scores 2×, just like guessing double.

How the napkin math would have scored

Fermi's rough working for this question ends at ≈ 29 days. Typed in as a guess, that comes back Too Low and scores 1.03×, landing about 3% under the real number.

The other questions in Fermi #75 were How many wild elephants lived in Africa at the last full continent-wide count, published in 2016? (415,000 elephants) and How many Oreo cookies are sold around the world each day? (164,000,000 Oreos). All three answers are on the Fermi #75 answers page.

Frequently asked questions

What is the Fermi answer to "How many days does a container ship take to sail from Shanghai to Rotterdam through the Suez Canal?"

30 days. It was question 1 of Fermi #75, Friday, October 9, 2026.

What guess scores 2× on this Fermi question?

Anything from 15 to 60 days. For 10× or better, anything from 3 to 300 days works.

How can you estimate this without looking it up?

The sea route from Shanghai to Rotterdam covers about 20,000 kilometers, or half the distance around the world. A giant cargo ship may travel at 30 km/h, about the speed of a bike. That is roughly 700 kilometers per day. That route ends at ≈ 29 days.

Where does this Fermi answer come from?

Notteboom, Pallis & Rodrigue, Port Economics, Management and Policy: Routing Options between Shanghai, Rotterdam and New York.

How does Fermi scoring work?

Each guess turns into a multiple: the larger of your guess and the answer, divided by the smaller. Exact is 1×, off by double or by half is 2×, and ten times off is 10×. The three multiples are then combined with a geometric average (multiply them, take the cube root) to give the day score. Lower is better.

Where can I play Fermi?

In any web browser at fermi.gg. It's free, and you can play without an account. Signing in adds the leaderboard, the stats page and your history on every device.