ISKRIT / Site investigation & geotechnics / Relative density of sand
Site investigation & geotechnics
Relative density calculator: Dr, Id and density of packing (ASTM D4253 / D4254)
From the maximum and minimum index densities and the in-place dry density the tool computes relative density Dr, density index Id and the void ratios, then names the density of packing per the selected standard. Specific gravity is optional: Dr does not depend on it.
Data current as of 2026-08-24
Standards
ASTM D4253 (maximum index density, vibratory table) and ASTM D4254 (minimum index density and the calculation of relative density), EN ISO 14688-2 for the density of packing.
Input
Maximum and minimum index density, in-place dry density or moist density with water content. Specific gravity and sand coarseness optional.
Output
Dr, Id, e, emax, emin, density of packing.
What it does
- Relative density Dr from index densities or directly from emax and emin
- Density index Id reported separately: the two are routinely confused
- Void ratios in place, in the loosest and in the densest state
- Density of packing per ASTM and EN ISO 14688-2
The tool and the platform
The tool
- Relative density, void ratios and the density state of the sand
- Load samples from an Excel template, printable report
- Calculations are stored on the server and reopen next time, company letterhead with signatures
- Works instantly, no sign-up required
ISKRIT·Geo demo
The work of a whole department: roles, history and modules linked together.
- Relative density results are kept with the site samples
- The density state goes into the unit name
- One schedule across every sample on the site
Questions
What is the difference between relative density Dr and density index Id?
Dr is defined through void ratios: Dr = (emax − e)/(emax − emin). Id is linear in densities: Id = (rd − rd min)/(rd max − rd min). In terms of densities Dr = Id · rd max/rd, so Dr is never smaller than Id, and using one in place of the other understates how dense the soil really is. The tool reports both.
Do I need the specific gravity of solids?
Not for Dr: it cancels out of the formula. It is only needed to display the void ratios and to name the density of packing, which follows from the void ratio and the grain size.
ASTM D4253 and D4254 were withdrawn, what should I use?
ASTM withdrew both test methods in 2025 with no replacement, yet laboratories still run them and specifications still cite these designations. The relative density calculation itself did not change, so the tool keeps the original formulas and the original names.
Why did Dr come out negative or above 100 %?
The in-place dry density fell outside the index densities. That is a discrepancy between tests rather than a calculation error: the tool reports the value as it is, warns about it, and assigns no density class.