The density curves for Skydrol LD-4, Skydrol 500B-4, and Skydrol 7000 were digitized from The Lee Company's published "Specific Gravity of Typical Fluids vs. Temperature" chart, which reports specific gravity across a wide −80 °F to 320 °F range. Specific gravity was converted to density using a water reference of 999.01 kg/m³ at 60 °F, the same reference used site-wide, then linearly interpolated between digitized points.

This curve data was independently cross-checked against Eastman's own measured 25 °C (77 °F) density values published in the Skydrol product comparison brochure. The interpolated Lee Company curve lands within about 0.3 % of Eastman's measured value for 500B-4 and about 0.7 % for LD-4 — close enough to use with confidence across the full temperature range, though the brochure's single-point typical values remain the more precise reference at 25 °C specifically.

"Skydrol 7000" is an older/regional marketing name; it is included here because a validated full-range curve exists for it, but it may not be chemically identical to the current Skydrol 5 product line. No published temperature-vs-density curve is currently available for Skydrol PE-5 or the current Skydrol 5 formulation — only their single 25 °C data points are known — so those two grades are not included in this calculator.