How to read big numbers

The four-step method

1. Start at the right. Separate the digits into groups of three. These groups are often called periods.
2. Name the groups. Moving left, the groups are ones, thousands, millions, billions, and trillions.
3. Read each non-zero group. Treat every group as a number from 1 to 999. Skip any group containing 000.
4. Add the group name. Read from the largest group to the ones group and join the parts together.

Worked example: 4,567,891,230

Read each group in order:

Four billion, five hundred sixty-seven million, eight hundred ninety-one thousand, two hundred thirty.

In Australian and British English, speakers often include and inside a three-digit group: “five hundred and sixty-seven.” The place-value method stays the same whichever wording style your school uses.

What happens when a group is zero?

Do not say the name of an empty group. For example, 8,004,012 has the groups 8 | 004 | 012. It is read as:

Eight million, four thousand, twelve.

The hundreds and tens inside a group may also be zero. The number 205,070 is “two hundred five thousand, seventy.” You only say the values that are present.

Place-value group names

Try these three numbers

Fast check: count comma-separated groups, not individual zeroes. One group after the leading group means thousands; two means millions; three means billions; four means trillions.

Common mistakes to avoid

• Reading every digit separately instead of reading three-digit groups.
• Saying an empty group, such as “zero million.”
• Counting zeroes from the left and losing your place.
• Using a plural group name inside one number. Say “five million,” not “five millions.”