Calculator
Example data table
| # | Shape | Length | Depth | Top width | Bottom width | Method | Allowance | Solution needed (approx.) |
|---|---|---|---|---|---|---|---|---|
| 1 | Rectangular | 30 m | 0.15 m | 0.15 m | 0.15 m | Fill trench | 8% | ~729 L |
| 2 | V-shaped | 20 m | 0.20 m | 0.18 m | 0.06 m | Apply by length (5 L/m) | 10% | ~110 L |
| 3 | Rectangular | 120 ft | 6 in | 6 in | 6 in | Apply by length (0.4 gal/10ft) | 12% | ~5.4 gal |
Formula used
- Rectangular cross-section: Area = width × depth.
- V-shaped (trapezoid) cross-section: Area = ((top width + bottom width) ÷ 2) × depth.
- Trench volume: Volume = cross-section area × length.
- Liters: liters = m³ × 1000. US gallons = liters ÷ 3.78541.
- Allowance: adjusted volume = base volume × (1 + allowance% ÷ 100).
- Length method: solution = (rate in L/m) × length, then allowance.
- Area method: solution = (rate in L/m²) × (length × top width), then allowance.
- Concentrate helper: concentrate (mL) = (mL/L) × solution liters.
How to use this calculator
- Pick a trench shape that matches your excavation.
- Select the unit you used when measuring the trench.
- Enter length, depth, and top width. Add bottom width for V-shaped.
- Choose an estimation method: fill, by length, or by area.
- If using length/area, enter the rate from your label or plan.
- Add an allowance to cover uneven soil and small losses.
- Press Calculate to see results under the header.
- Download CSV or PDF to document your plan.
Why trench volume accuracy matters
Accurate volume estimates help you stage enough diluted termiticide for a continuous barrier and avoid leftover mix. Underestimating can leave dry pockets in loose backfill or absorbent beds. Overestimating increases cost, handling, and disposal risk. This calculator converts field dimensions into liters and US gallons to support consistent planning. Use the allowance slider to reflect site losses.
Choosing a trench shape and measurements
Garden-edge trenches are often rectangular with a flat spade, but they may be V-shaped with trenching tools. Choose the profile that matches the soil cut you see. Measure length along the full run, including corners. Check depth in several spots and use a realistic average. Measure top width and, for V-shapes, the bottom width. For long runs, measure in segments and sum totals.
Interpreting solution methods and rates
The fill method treats the trench as a container and estimates the liquid needed to wet the whole excavation. Many labels specify linear rates, such as liters per meter or gallons per 10 or 100 feet. Use the length method to align with those directions. If dosing is based on surface coverage, the area method applies a rate to length × top width.
Allowance, soak-in, and mix planning
Soil texture, organic matter, and compaction influence soak-in. A modest allowance covers irregular walls, minor collapse, and absorption before backfill. Keep the margin conservative and validate with a short test section. The concentrate helper multiplies your mL per liter factor by total solution to estimate milliliters required. Always verify dilution and restrictions on the label. Mix only what you can apply safely within the allowed time.
Documenting work and keeping records
Good records improve crew communication and repeatable results. Note trench geometry, method, rate units, and allowance so future visits can mirror the approach. CSV exports support spreadsheets for job costing, while PDFs attach cleanly to service reports. Add brief site notes—standing water, heavy mulch, or prior treatments—because conditions can change absorption and staging needs.
FAQs
1) Should I use the fill method or a labeled rate?
Use the method that matches your product label or site specification. Fill is a volume-based estimate, while length and area methods follow rate-style instructions. When in doubt, default to the label.
2) What allowance percentage is reasonable?
Many crews start with 5–12% for irregular edges and soak-in, then adjust after a short test section. Very sandy or highly absorbent soils may need a higher margin.
3) How do I measure a trench around corners and steps?
Break the run into straight segments, measure each segment, then add them together. Include returns at steps, posts, and utility penetrations if they will be treated.
4) Why does the V-shaped option ask for bottom width?
A V-shaped trench has sloped sides, so the cross-section is a trapezoid. Bottom width captures how narrow the trench is at the base, which changes area and volume.
5) Does the concentrate helper replace label mixing instructions?
No. It only multiplies your entered mL-per-liter factor by the computed solution volume. Always confirm dilution, application limits, and safety requirements on the product label.
6) Can I export results for job reports?
Yes. CSV works well for spreadsheets and cost tracking, while PDF is easier to attach to a service record. Exports use your most recent calculation stored in the session.