Math2
Math2.org: Weights and Measures
This resource provides information on weights and measures, including unit conversion tables.
University of Waterloo (Canada)
University of Waterloo: Metric 4
Test your knowledge at metric conversion by answering 30 questions on distance, length, volume, and weight.
The Math League
The Math League: Metric Units and Measurement
This metric system tutorial is compared to the U.S. standard system so that students can comprehend the measurement of length, volume, mass and the like.
Other
Metric Conversion Calculator and Charts
Metric Conversions offers online calculators for making conversions, downloadable tables in many types of metric conversion (pdf format), and free conversion tools to put onto your website or dynamic pages.
Math Is Fun
Math Is Fun: Metric Area
The relationships between metric units of area are explained, with examples of how to calculate area.
Khan Academy
Khan Academy: Estimating Length (Mm, Cm, M, Km)
Practice estimating the length of real life objects using metric units. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Khan Academy
Khan Academy: Convert to Smaller Units (Mm, Cm, M, & Km)
Practice converting a metric measure of length to a smaller unit. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Science Made Simple
Science Made Simple: Online Metric Converter
Practice converting English units of measurement to metric units using this tool.
Math Is Fun
Math Is Fun: Metric Length
The different units used to measure metric length are described, with comparisons to real world objects. A wonderful number line also shows the relative sizes of things all the way from a quark to the universe in powers of ten.
Other
Science Made Simple: Area Conversions
This site, which is provided for by Science Made Simple, allows you to enter an amount into an area conversion calculator.
CK-12 Foundation
Ck 12: Measurement: Metric Length Comparison
[Free Registration/Login may be required to access all resource tools.] Convert metric lengths to the same unit and compare.