Measure how soil settles after tamping in beds. Compare volumes or densities quickly for planning. Reduce guesswork, order the right material, and save money.
| Date/Time | Method | Compaction factor | Shrinkage % | Loose needed (if target) | Notes |
|---|---|---|---|---|---|
| Add results to build an exportable list. | |||||
| Scenario | Loose Volume (m³) | Compacted Volume (m³) | Compaction Factor | Shrinkage % |
|---|---|---|---|---|
| Raised bed fill (screened loam) | 0.50 | 0.40 | 1.2500 | 20.00% |
| Path base (crushed gravel) | 1.20 | 1.00 | 1.2000 | 16.67% |
| Potting mix (light, fluffy) | 0.30 | 0.24 | 1.2500 | 20.00% |
Compaction changes pore space, settlement, and finished grade. A reliable factor helps you predict how much loose material becomes a stable layer after tamping. It reduces rework on raised beds, paths, and backfill where consistent thickness matters. It also supports better drainage decisions because overly dense soils can restrict infiltration and root growth. For turf areas, moderate compaction improves contact, but excessive compaction increases runoff and encourages shallow rooting during dry periods too often seasonally.
The most dependable approach is a small test section. Place loose soil in a box or framed area, level it, and record the loose volume. Compact using the same tool, lift thickness, and number of passes planned for the job, then remeasure the compacted height or volume. Repeat twice and use the average to smooth out operator variation.
When you can measure bulk density, compaction factor can be derived from the ratio of compacted to loose density. This is useful when volume is hard to track in irregular spaces. Keep moisture similar between readings to reduce drift, and note the soil texture. Sandy mixes often show smaller changes than high organic blends or fluffy potting media.
Once you know the factor, multiply your required compacted volume by the factor to estimate loose material needed. Add a contingency for waste, spreading losses, and edge trimming, especially on curved borders. For layered builds, calculate separate factors for base and topping. Document results by supplier, because loads can vary by screening and moisture.
Errors usually come from mixed materials, changing moisture, and inconsistent lift thickness. Compacting thick lifts can trap soft zones that settle later. Recheck measurements after rainfall or irrigation and confirm the surface feels firm under foot traffic. If results vary widely, repeat the test, correct your method, and average the most consistent factors before ordering.
It is the ratio of loose volume to compacted volume. A factor above 1.0 means the material settles and occupies less space after compaction.
Yes. Aggregate, sandy loam, and compost behave differently. Measure each layer using the same lift thickness and compaction method you will use on site.
Use a framed box or a marked area with known length and width. Measure loose and compacted depths with a ruler, then compute volume from area times depth.
Moisture affects particle lubrication and how easily soil rearranges. Very dry soil resists compaction, while overly wet soil can pump and lose strength, giving inconsistent readings.
Many garden fills fall between about 1.05 and 1.35, but organic mixes can vary more. Always test your specific material and method for better accuracy.
Add a small allowance for spillage, uneven subgrades, and trimming. For small projects, 5–10% is common, but adjust based on access, handling, and experience.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.