Big Number Calculator

This big number calculator works out calculations with very large numbers and gives you every digit, not a rounded 1.2E30. Type a whole calculation such as 2^1000, 100! or 123456789012345678901234567890 × 987654321, and the answer appears as you type, with the number of digits, the sum of its digits, its name (like quattuordecillion) and its scientific notation. You can also enter two numbers X and Y and press a button, or get divisions and square roots to as many as 5,000 decimal places.

How to Use the Big Number Calculator

1. Type or paste a calculation. Use + − × ÷, ^ for powers and ! for factorials, or the buttons under the box. Numbers with commas such as 1,234,567 are fine.
2. Or use two numbers. Open Two numbers (X, Y), paste X and Y and press X + Y, X × Y, X^Y, GCD or another operation.
3. Pick the decimal places for divisions, roots and logarithms. Whole-number results are always exact.
4. Read and copy the result. Switch between decimal, scientific notation, hex and binary, turn digit grouping on or off, and copy it. Press Enter to keep a calculation in your history, and type ans to use the last result.

What You Can Type

Names of Big Numbers

Every result of a million or more gets a name. In English each new name is a thousand times bigger than the last (the short scale):

A googolplex, 10^googol, has more digits than there are atoms in the observable universe, so no calculator can write it out.

Exact or Rounded?

Whole-number calculations (adding, subtracting, multiplying, powers, factorials, GCD, LCM, combinations and mod) are exact to the last digit. A division that does not come out even, like 1/7, never ends, and neither do square roots like √2, pi or logarithms, so they are rounded to the decimal places you pick. The label above each result tells you which it is. Very small results are rounded to that many significant digits instead, so 0.5^1000 still shows its real digits rather than 0.

Frequently Asked Questions

How big a number can this calculator handle?

Results are written out in full up to one million digits, so 2^1000, 1000! or even 200,000! show every digit. For anything larger, such as 9^9^9, the calculator still tells you its size in scientific notation and how many digits it has.

Are the results exact?

Adding, subtracting, multiplying, powers, factorials, GCD, LCM, combinations and mod of whole numbers are always exact. Divisions that do not come out even, square roots and logarithms are rounded to the number of decimal places you choose, and the result is labeled Exact or Rounded so you always know which one you have.

Why does my normal calculator show 1.2676506E30 instead of the full number?

Phone and school calculators keep only about 10 to 16 significant digits, so very large results are shown in scientific notation and the rest of the digits are lost. This calculator works with every digit, so 2^100 shows as 1,267,650,600,228,229,401,496,703,205,376.

How do I calculate a large factorial like 100!?

Type 100! and the result appears at once: a 158-digit number. The calculator also shows the sum of its digits (648) and how many zeros it ends with (24).

How many digits is 2 to the power of 1000?

2^1000 has 302 digits and starts with 10715086071862673209. The sum of its digits is 1366. Type 2^1000 to see all of them.

What is a googol, and what comes after a trillion?

In the short scale used in English, each new name is 1,000 times bigger: million (10^6), billion (10^9), trillion (10^12), quadrillion (10^15), quintillion (10^18), up to vigintillion (10^63). A googol is 10^100, a 1 followed by 100 zeros, and a centillion is 10^303. The calculator names every result for you.

Can I calculate a^b mod m for cryptography homework?

Yes. Type it as one expression, for example 13^37 mod 1000003, or use the % sign. Whole-number results can also be shown in hexadecimal and binary, and gcd() and lcm() take as many numbers as you like.

How do I get the square root of 2 to 1,000 decimal places?

Choose 1,000 in Decimal places and type sqrt(2) or √2. You can choose up to 5,000 decimal places, and the same works for 1/7, pi, e and ln(2).

Is the Big Number Calculator free and private?

Yes. Calculating, copying results and the history are free with no sign-up, and everything is calculated in your browser, so nothing you type is sent anywhere. Saving a result as a .txt file is part of the paid plans.