R-value or rvalue may refer to:

• R-value (insulation) in building engineering, the efficiency of insulation of a house
• R-value (soils) in geotechnical engineering, the stability of soils and aggregates for pavement construction
• R-factor (crystallography), a measure of the agreement between the crystallographic model and the diffraction data
• R₀ or R number, the basic reproduction number in epidemiology
• In computer science, a pure value which cannot be assigned to
• In statistics, the Pearson product-moment correlation coefficient, or simply correlation coefficient
• In solid mechanics, the Lankford coefficient

• L-value (disambiguation)
• R rating (disambiguation)
• R-factor, a plasmid that codes for antibiotic resistance
• ASHRAE refrigerant designations, commonly known as R-numbers