Short answer: there’s no single allowance — it depends on the carrier and your fare class. Typical allowances for the main operators on Colombo (CMB) — Kuala Lumpur (KUL) are:

• SriLankan Airlines — Economy: usually a 30 kg checked allowance (SriLankan also publishes a piece-based table showing Economy as 2 pieces up to 23 kg each on some routings); Business: larger (40 kg or 2 × 32 kg by piece). Cabin baggage: 1 piece up to 7 kg (Business passengers allowed 2 pieces). (srilankan.com)

• Malaysia Airlines — Cabin: Economy 1 piece up to 7 kg (Business 2 pieces up to 14 kg total). Checked baggage is by weight and depends on fare family/ticket: economy fares commonly range from ~20 kg (lite/basic) up to 35 kg (higher fare families); Business fares are typically 40–55 kg. Check your fare class for the exact allowance. (malaysiaairlines.com)

• Batik Air Malaysia (formerly Malindo/Malaysia-based Batik) — Checked baggage varies by fare: Economy Value ~20 kg, Economy Flexi ~30 kg, Business 30–40 kg (see their baggage table). Cabin: Economy 1 piece up to 7 kg; Business allowances are larger. (malindo-airways.com)

• AirAsia (including long‑haul AirAsia X on some services) — Low‑cost model: most lowest fares do NOT include checked baggage. Cabin allowance normally 2 items combined up to 7 kg; checked bags (e.g., 20 kg) must be bought as an add‑on or with a bundled fare (Value Pack / Premium). (airasia.com)

Important: these are general summaries — exact allowance depends on the airline operating your specific flight, the fare family/ticket you bought, frequent‑flyer status, and whether the flight is codeshare/interline. I can look up the exact allowance for your ticket if you tell me the airline and fare family or show your booking reference.