Guess a unit conversion in your head, then enter it here to see the exact answer and how accurate your guess was.
This tool supports common length units (in, ft, yd, mi, cm, m, km), weight units (oz, lb, g, kg), and volume units (tsp, tbsp, cup, floz, l, ml, gal). It compares your guess to the exact converted value and reports your percentage error and an accuracy score out of 100.
Value:
From unit: To unit:
Your guess:
How It Works
This tool supports common length units (in, ft, yd, mi, cm, m, km), weight units (oz, lb, g, kg), and volume units (tsp, tbsp, cup, floz, l, ml, gal). It compares your guess to the exact converted value and reports your percentage error and an accuracy score out of 100.
How to Use This Tool
- Enter the starting value.
- Enter the unit you are converting from and the unit you are converting to.
- Enter your mental-math guess for the converted value.
- Click Check My Guess to see the exact answer and your accuracy score.
This is a fun way to sharpen mental-math conversion skills for cooking, travel, fitness, or everyday estimates; the two units must be from the same category (both lengths, both weights, or both volumes) to get a result.
Did You Know?
- Estimation shortcuts like “a kilometer is about six-tenths of a mile” or “a kilogram is about 2.2 pounds” can get you remarkably close without a calculator.
- The US is one of the few countries that still primarily uses the imperial system for everyday measurements like recipes and road distances.
Frequently Asked Questions
Which units are supported?
Length (in, ft, yd, mi, cm, m, km), weight (oz, lb, g, kg), and volume (tsp, tbsp, cup, floz, l, ml, gal).
Can I convert between weight and volume?
No, the two units need to be from the same category since weight and volume are not directly convertible without knowing a substance’s density.