Work out how many rolls of underground warning tape you need to cover your trench runs, and what it'll cost.
Calculate rolls needed
Advanced options (roll length & price)
How this calculator works
We multiply your trench length by the number of separate tape runs you need, add a wastage allowance for overlaps and offcuts, then divide by the roll length to get the number of rolls:
Rolls needed = (trench length × runs × (1 + wastage%)) ÷ roll length
Non-detectable underground warning tape is commonly supplied in 365m rolls at 150mm wide, while detectable tape with a metallic tracer wire (for locating buried non-metallic pipes from ground level) is often supplied in shorter 100m rolls. Adjust the roll length above to match your chosen product.
Installing underground warning tape correctly
Lay it during backfilling, not after
Warning tape should go down as the trench is backfilled — not laid on top of the finished surface, and not stuck directly to the pipe or cable. Best practice is to lay it loosely, roughly 300mm above the service line, so excavation tools reach the tape and give a clear warning before reaching the buried utility.
Colour coding
| Colour | Typically used for |
|---|---|
| Red | Electric cables |
| Yellow | Gas mains |
| Blue | Water pipes |
| Green | Sewer / drainage |
| Orange | Telecoms / fibre optic |
| Purple | Reclaimed water |
Detectable vs non-detectable
Non-detectable tape is a visual-only marker for excavators to see during digging. Detectable tape includes a metallic element that can be traced from ground level with a locating tool before you start digging — worth using where you need to confirm a route in advance.
Frequently asked questions
How deep should the tape be buried?
A typical burial depth is around 12–18 inches (roughly 300–450mm) above the service, though always follow the specific requirements of the utility owner or your site's method statement.
Can I use one tape colour for multiple services?
No — use the correct colour and wording for each service to avoid confusion for anyone excavating in the future. If a trench carries multiple services, lay a separate, correctly labelled tape run for each one.
What width should I use?
150mm tape is commonly used for lines down to around 36 inches deep, while narrower 50mm tape is often used for shallower utility lines up to about 12 inches. Check your project specification if one is provided.
Check out our other calculators!
Garage Floor Paint CalculatorCark Park Dimension & Layout CalculatorFirewood Quantity CalculatorCar Park Bay Lining Calculator