Free online calculators for civil and structural engineers. Convert units between metric and imperial systems, scale SI prefixes, convert coordinates between decimal and DMS formats, and learn how to work with scientific notation.
Unit converter
Convert between imperial and metric units across 10 categories — length, area, volume, mass, pressure, speed, temperature, force, energy, and angle.
Open calculator →
SI prefix scaler
Scale values between SI prefixes — from yotta (10²⁴) to atto (10⁻¹⁸). Instantly convert mm to m, kN to N, MPa to Pa, and any other prefix combination.
Open calculator →
Degrees & minutes
Convert between decimal degrees and DMS (degrees, minutes, seconds). Also converts radians to degrees and calculates road slope percentage and grade.
Open calculator →
Scientific notation guide
Step-by-step guide to converting values in scientific notation to SI units. Learn how to handle mm³, kN, MPa and other common engineering units correctly.
Read guide →
Frequently asked questions
What units does the engineering unit converter support?
The converter supports 10 categories: length (inch, foot, mile, mm, cm, m, km), area, volume (including cubic mm and cubic feet), mass, pressure (psi, kPa, MPa, bar), speed, temperature (°F, °C, K), force (lbf, kip, N, kN), energy, and angle.
How do I convert psi to MPa?
1 psi = 0.006895 MPa. Open the Unit converter, select Pressure category, choose psi as the From unit and MPa as the To unit, then enter your value. The result appears instantly.
How do I convert mm³ to m³?
1 mm³ = 10⁻⁹ m³. This is because mm = 10⁻³ m, and when cubed: (10⁻³)³ = 10⁻⁹. Use the SI prefix scaler to convert any cubic unit combination quickly.
What is the difference between decimal degrees and DMS?
Decimal degrees express a coordinate as a single number (e.g. 48.8566°). DMS splits it into degrees, minutes, and seconds (e.g. 48° 51′ 23.76″). Both represent the same location — use the Degrees & minutes converter to switch between them.