Here is the answer to questions like: What is the base 10 logarithm of 100? or what is the base 10 log of 100?
Use the | Log10 calculator below to find the logarithm of any positive number for any number base you enter.
What is logarithm?
A logarithm is the power to which a number must be raised in order to get some other number. In other words, the logarithm tells us how many of one number should be multiplied to get another number.
- The base 2 logarithm of 4 is 2, because 2 raised to the power of 2 is 4:
- log3 9 = 2, because 32 = 9
This is an example of a base-3 logarithm. We call it a base-3 logarithm because 3 is the number that is raised to a power.
The most common logarithms are natural logarithms and base 10 logarithms. There are special notations for them:
- A base 10 log is written simply log.
- A natural logarithm is written simply as ln.
So, the notation log alone means base ten logarithm and notation ln, means natural log.
Basic Log Rules
- logb(x·y) = logb(x) + logb(y)
- logbx/y) = logb(x) - logb(y)
- logb(xy) = y·logb(x)
- logb(x) = logk(x)/logk(b)