Decking Ratio Calculator
Computes charged, inert, air, stemming and unassigned ratios from a collar-to-toe deck stack measured along the hole, refusing overlaps and showing gaps instead of calling them stemming.
Inputs
Charged, inert, air, stemming and unassigned ratios from a collar-to-toe deck stack — overlaps and out-of-hole intervals are refused, gaps are shown.
Enter the values and press Calculate.
Or load an example to see a worked result.
Before you rely on this: First-pass guide only. Verify safety-critical or regulated work against the relevant standards, your project requirements and a qualified professional.
How to use this calculator
- Enter the hole length measured along the hole from collar to toe, including subdrill.
- List each deck as type, from, to — explosive, inert, air or stemming — with depths from the collar. Or switch to the simple mode with one total charged length.
- Read the charged ratio, the other deck ratios, any unassigned gaps and, with a diameter and density, the explosive mass.
How it works
Charged ratio = Σ explosive deck lengths ÷ hole length. Inert, air, stemming and unassigned lengths are reported separately — a gap is never assumed to be stemming.
Overlapping decks and decks outside the hole are refused with their line numbers; zero-length intervals are excluded and listed.
Optional mass = density × π × d² ÷ 4 × charged length (kg/m³ and metres), assuming a full-diameter column with no voids.
Worked example
10 m hole, 7 m of explosive. 7 ÷ 10 = 70 % charged and 3 m uncharged. With stemming 0–3 m and explosive 3–9 m the ratio is 60 % and 1 m (9–10 m) is unassigned. With stemming 0–2.5, explosive 2.5–5, inert 5–6 and explosive 6–10 m the hole is 65 % charged, 10 % inert and 25 % stemming.
Frequently asked questions
Along-hole or vertical length?
Along the hole, collar to toe. For an angled hole that is longer than the vertical depth, and it includes subdrill — it is not the bench height.
Is all uncharged length stemming?
No. Uncharged length can be stemming, inert decks, air decks or simply unrecorded. The deck stack keeps them apart and shows any gap as unassigned.
How are overlaps handled?
They are refused. Each depth can belong to only one deck, so the tool names the overlapping lines instead of merging or trimming them silently.
What is decking?
Splitting the column into separate charges with inert or air decks between them. This tool accounts for the lengths; it does not advise on deck design, initiation or safety.
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Cite this tool
Zerdly. (2026). Decking Ratio Calculator. Retrieved from https://www.zerdly.com/tools/decking-ratio-calculator/
Tip: Enter any known values to calculate the remaining results.
Designed to run locally in your browser. Tool inputs are not intentionally stored by Zerdly unless stated otherwise.