Custom calculation workbooks, trackers and automations — built to your standards, documented, and owned by you.
Every engineering team has that spreadsheet — the one nobody fully trusts, with the formula someone changed in 2019. We build the opposite: bespoke Excel tools engineered like deliverables — inputs validated, calculations locked and referenced to the standard clause, assumptions documented, results presented as a printable report your checker can sign off.
And not just calculators: project trackers, cable schedules, drawing registers and management dashboards — with Power Query, VBA and database integration where it genuinely earns its keep.
Three illustrative extracts from tools we've built — generic example data, same structure as the real project versions:
| A | B | C | D | |
|---|---|---|---|---|
| 1 | CABLE CLEAT SPACING CALCULATOR — IEC 61914 / BS EN 61914 | |||
| 2 | 1. INPUTS (blue cells) | |||
| 3 | Peak fault current, î | 40.0 | kA | From protection study |
| 4 | Formation | Trefoil, 3 × 1C | — | Dropdown — sets coefficient K |
| 5 | Cable outer diameter | 32.0 | mm | From cable datasheet |
| 6 | Cleat rated withstand, Fₖ | 3.0 | kN | Manufacturer test cert |
| 7 | 2. RESULTS (locked) | |||
| 8 | Force between conductors | 8.50 | kN/m | = 0.17 × î² / d (N/m) |
| 9 | Maximum cleat spacing | 353 | mm | = Fₖ / force per metre |
| 10 | Recommended spacing | USE 300 mm CENTRES ✓ | mm | Rounded to rung pitch |
1Blue cells are the only thing you touch. Everything else is locked, so the tool survives being passed around a project team.
2Every result traces to a clause. Formulas reference the standard (IEC 61914, BS 8519, BS 7671…) and the source of each input is stated on the sheet.
3Manufacturer data built in. Cleat, cable and fixing libraries live on hidden data sheets — pick from a dropdown instead of retyping datasheets.
4A verdict, not just a number. The sheet answers the actual question ("what spacing do I install?") and prints as a calculation report with a notes & assumptions page.
On fire-rated escape routes and life-safety circuits, every containment support must survive the fire condition — BS 8519 limits the drop rod stress far below its ambient capacity, and a bracket that passes at ambient can fail the 2-hour case. This tool takes the services load and the bracket geometry, builds the load from first principles, and runs every failure mode in one pass:
| A | B | C | D | |
|---|---|---|---|---|
| 1 | BRACKET CALCULATION — TRAPEZE DROP ROD (BS 8519:2020 E.1) | |||
| 2 | 1. INPUTS (blue cells) | |||
| 3 | Services load (cables + containment) | 49.0 | kg/m | Itemised or combined entry |
| 4 | Hanger spacing, Lₕ | 1.2 | m | Spacing along the run |
| 5 | Drop rod length / bearer length | 1.0 / 1.0 | m | Trapeze geometry |
| 6 | Fire / service condition | Ambient | — | Dropdown: Ambient / 0.5 / 1 / 2 h — sets σmax per BS 8519 Table E.1 |
| 7 | Safety factor, γₖ | 1.3 | — | Project / Eurocode basis |
| 8 | 2. LOAD BUILD-UP (locked) | |||
| 9 | Total mass (services + bearer + rods) | 62.3 | kg | = Wₛₓₜ × Lₕ + bearer + 2 rods |
| 10 | Unfactored / design load | 0.61 / 0.79 | kN | F = m × g; Fₓ = F × γₖ |
| 11 | 3. CHECKS (locked) | |||
| 12 | 1 — Drop rod stress (M12) | PASS ✓ | — | Req. 3.1 mm² ≤ 76.3 mm² at minor dia |
| 13 | 2 — Bearer / strut capacity | PASS ✓ | — | 0.61 kN ≤ 1.45 kN rated at span |
| 14 | 3 — Channel nut shear (2 nuts) | PASS ✓ | — | 0.40 kN/nut ≤ 3.0 kN rated slip |
| 15 | 4 — Concrete anchor pullout (2 anchors) | PASS ✓ | — | 0.40 kN/anchor ≤ 1.0 kN design value |
| 16 | OVERALL STATUS | ALL CHECKS PASS ✓ | — | Prints as a signed calc sheet |
1One dropdown drives the fire case. Selecting Ambient / 0.5 / 1 / 2 h changes the allowable rod stress per BS 8519 Table E.1 and every check re-runs instantly — no separate "fire version" of the spreadsheet to keep in sync.
2Four failure modes, one verdict. Rod stress, bearer capacity, channel nut slip and anchor pullout are checked together, because the weakest link governs — a bracket is not "PASS" until all four are.
3Manufacturer values, referenced. Strut capacities, nut slip loads and anchor design values come from published tables held on data sheets — the calc states where each number came from.
4Scales across a project. Each bracket detail is a copy of the sheet; the original tool this example is based on runs dozens of bracket details in a single workbook, one summary page for the checker.
A ladder full of cleated single-core or SWA cables has two questions: is the ladder overloaded, and do the cleats physically fit? The second one is routinely missed — a cleat is wider than its cable, so on close-spaced cables the cleats collide on the rung, and nobody discovers it until the installer does. This tool checks the weight and the geometry together:
| A | B | C | D | |
|---|---|---|---|---|
| 1 | CABLE LADDER LOADING & CLEAT ARRANGEMENT | |||
| 2 | 1. INPUTS (blue cells) | |||
| 3 | Cable | 4C × 120 mm² Cu/XLPE/SWA | — | OD 44.9 mm, 6.44 kg/m from datasheet |
| 4 | Number of cables | 7 | no. | Per site sketch |
| 5 | Cleat (two-bolt LSF) | 92 mm wide | — | From manufacturer library |
| 6 | Clear gap between cables / rung pitch | 5 / 300 | mm | Design spacing; ladder rung pitch |
| 7 | 2. RESULTS (locked) | |||
| 8 | Ladder loading | 45.1 | kg/m | = 7 × 6.44 — check vs ladder SWL |
| 9 | Cleat fit on shared rung | CLASH | — | Cleat 92 mm > cable pitch 49.9 mm |
| 10 | Arrangement | STAGGER — ALTERNATE RUNGS, S = 600 mm ✓ | — | Drawn live on the diagram sheet |
1Weight and geometry in one pass. The loading check (cables per metre vs ladder safe working load) and the cleat-fit check share the same inputs, so they can't drift apart.
2Clash detection. The tool compares cleat width against the cable pitch (OD + design gap). Here 92 mm > 49.9 mm — cleats cannot share a rung, so it staggers them onto alternate rungs and recalculates the effective spacing per cable.
3A live drawing, not a description. The workbook redraws the plan view below as the inputs change — the installer sees exactly which rung each cleat lands on.
4Cable and cleat libraries. OD, weight and cleat dimensions come from built-in manufacturer-typical data sheets, replaceable with datasheet values for the actual cable.
This is the plan view the workbook produces for the example above:
A single-purpose calculator (one calculation, one standard) typically runs £400 – £1,500. Multi-sheet suites with manufacturer libraries, VBA automation or database integration typically run £1,500 – £5,000+, scoped individually. As with our design services pricing, you get a fixed quote before we start.
Common questions about commissioning bespoke Excel tools.
You do. We hand over an unlocked workbook with the formulas visible, a notes sheet documenting assumptions, standard clauses and limitations, and no licence strings attached. Your team can extend it or we can maintain it — your choice.
Yes. Most calculators can be built formula-only, which runs in any corporate environment including Excel Online and SharePoint. We use VBA or Office Scripts only where genuinely needed — batch processing, report generation, or data imports — and agree that with you first.
Every tool ships with worked test cases checked against hand calculations or published examples from the relevant standard, and the assumptions sheet states exactly what the tool does and does not cover. For safety-critical calculations we recommend an independent check, which we can arrange or your engineer can do against the documented method.
Usually yes. We can tidy, verify and extend an existing workbook — adding proper input validation, locked calculation areas, manufacturer data tables, and printable report sheets — often faster than starting from scratch.
Yes. Using Power Query and standard connectors, workbooks can pull from and publish to SQL databases, SharePoint lists and CSV exports from other systems — useful for cable schedules, drawing registers and progress trackers that several people update.