Large numbers are abstract. I experimented with different ways to more closely feel these scales and discovered a personally effective approach using division and per-second counting.

The Against Malaria Foundation has protected 611,336,286 people with insecticide-treated nets.

1. Divide by seconds in a week (604,800), giving approximately 1,000 people per second
2. Count aloud: "1 one thousand, 2 one thousand, 3 one thousand..."
3. Imagine doing it every second for a week

Let's try a larger number: Toby Ord calculates our "affectable universe" as having at least 10²¹ stars.

1. Divide by Earth's projected peak population (10 billion), yielding 100 billion stars per person
2. Divide by seconds in a century (3.16 billion), giving approximately 31 stars per person per second
3. Count aloud: "31 Mississippi, 62 Mississippi, 93 Mississippi..."
4. Imagine doing it every second for a century

Counting by 31s disrupts the familiar rhythm of adding single digits. Disruptive "Mississippi counting" works for more per-second quotients than just 31.

The full effect comes from simultaneously holding the count, what each increment represents, and the full timespan in mind.

I'm interested in learning what techniques others use to feel large numbers.

Index cards are good at externalizing, organizing, and engaging with thoughts.

They're small enough to focus thoughts without needing to fill space. Cards can have multiple thoughts, or just one. This is what my ADHD has found to be useful and low-friction:

Organization

• Reorganize, discard, or add cards fast
• Arrange on desk/floor to see connections
• Stack to show categories, priorities, or dependencies
• Create visual hierarchies by physically overlapping cards (completely or partially)
• Remove unneeded cards from sight (out of mind)

Enhancements

• Color-code with pencils or cardstock (use paper guillotine for custom sizes)
• Hole-punch and add binder rings to keep ordered (hang from thumbtacks, carry in pocket)
• Print labels for highly-legible permanent information (useful for habits or workflows)
• Add stickers for fun or indication: I have one stack with the number of stickers indicating pomodoros completed, and flip to the next card on the ring after each session
• Add fabric with textile glue for tactile elements (polyester ribbon works well)

Warnings

• Paperclips can get stuck together or fall off
• Sticky tabs can also fall off