Branch 10 · free, no sign-up
Math Converters
The same quantity written a different way. These math converters show the formula rather than just the result, because the formula is the part that transfers to the next conversion you meet.
Every calculator in this branch is checked by a mathematician before it goes live.
- 25 °C the temperature
- 25 × 9⁄5 + 32 scale by 9/5, then shift by 32
- 77 °F 45 + 32
Calculators
All 7 converters calculators, by topic
grouped by what is being converted, not by direction
Temperature
Number Forms
Notation
Where this sits
What comes before converters
each topic assumes the one to its left
Stuck part way through? Start at the leftmost topic you are not sure about — everything to the right depends on it.
Knowledge base
Read the reasoning, not just the answer
one article per question a teacher would answer
Questions
Asked often enough to answer here
the ones that change how you work, not trivia
Why is temperature conversion not just multiplication?
Because the two scales do not start at the same place. Celsius puts zero at freezing and Fahrenheit does not, so you scale by 9/5 and then shift by 32. Miss the shift and every answer is wrong by 32 degrees.
Is there a temperature that reads the same on both scales?
Yes, −40. It is the one point where the two lines cross, and you can find it by solving C = C × 9/5 + 32.
Should I keep π in a radian answer?
Keep it unless you are asked for a decimal. 3π/4 is exact; 2.356 is rounded, and the rounding compounds if the value feeds into another calculation.
Nearby
Branches that touch this one
linked because the maths overlaps, not because it fills space