Mesh & rebar designation decoder
What does SL72, A142, 6×6-W2.9 or #4actually mean — and what's the nearest code in another region? Pick a common one, or ask about any designation.
Ask Leeter AI ↓Square mesh — 6.75 mm bars at 200 mm both ways · 179 mm²/m · 2.81 kg/m² · sheet 6.0×2.4 m
Cross-region: ≈ UK A193 (comparable steel area — not officially equivalent)
How this is calculated
- 1Three national systems, three encodings
AS/NZS 4671 (AU/NZ) SL/RL: S = square pitch, R = rectangular, and the trailing L = Grade 500L ductility; the number is a catalogue code that loosely tracks wire size (SL72 is 6.75 mm, not 7.2). BS 4483 (UK/EU) A/B/C: the most self-describing — the number IS the main steel area in mm²/m (A142 = 142 mm²/m). ASTM A1064 (US) spacing×spacing–W/D: W = smooth, D = deformed, and the number = wire area in hundredths of a square inch (6×6-W2.9 = 0.029 in² wire).
- 2Derivation
Every value is reproducible: area per metre A = (π/4)·d²×(1000/pitch) mm²/m, and areal mass = A×7.85×(directions)/1000 kg/m². Check: SL72 → (π/4)·6.75² = 35.8 mm², ×5/m = 179 mm²/m, ×7.85×2 = 2.81 kg/m².
- 3US bar sizes
#n = n/8 inch nominal diameter — but only for #3–#8 (#4 = ½ in = 12.7 mm). #9–#18 break the rule and are defined by area, a common professional gotcha the tool now flags.
- 4Comparable, not equivalent
A cross-region match aligns steel area per metre only; it does not transfer the grade, ductility class, weldability or code acceptance — the three standards use different grades (AS/NZS 500L, BS 500A/B/C, ASTM 65–80 ksi) and test methods. SL62 (141 mm²/m) vs A142 (142 mm²/m) match within 1% yet are not interchangeable on a stamped drawing. Confirm the governing standard from your drawings.
Leeter provides the tool, not a warranty of the result. Every figure above is a planning estimate for reference only — confirm structural, code and customs decisions with your engineer, inspector or broker.
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