What "premium" class sizes actually mean
Premium international schools (Tanglin Trust Singapore, HKIS Hong Kong, Dulwich College Beijing, Marlborough College Malaysia, ACS group London, etc.) target maximum class sizes of 18-22 students with full-time teaching assistants in primary years. Most schools publish target class sizes; actual class sizes can occasionally exceed targets when school is at capacity. Worth asking specifically during admissions visits. current actual class sizes (not just published targets) are the relevant data.
Typical class sizes by tier
Premium tier (USD 25,000+): primary 16-22, secondary 18-22, sixth-form 12-18. Most schools have full-time teaching assistants in primary years. Specialist subject teachers (music, art, PE) from year 1 onwards.
Upper-mid tier (USD 15,000-25,000): primary 18-25, secondary 20-25, sixth-form 14-22. Teaching assistants typically present in primary years but ratios less generous than premium tier.
Mid tier (USD 8,000-15,000): primary 22-28, secondary 22-28, sixth-form 16-25. Teaching assistant coverage variable. Specialist subject coverage from year 3-4 onwards.
Budget tier (under USD 8,000): primary 26-34, secondary 28-34, sixth-form 22-32. Teaching assistant coverage limited or absent. Specialist subject coverage variable.
How class sizes vary by curriculum
British-curriculum schools tend to have smaller class sizes than American-curriculum equivalents at similar fee tiers. IB Continuum schools typically have small primary classes (PYP focuses heavily on small group work) but standard secondary class sizes. American-curriculum schools sometimes run larger classes at upper-mid fee tier. CBSE/Indian-curriculum budget schools commonly run 32-40 per class.
The teaching assistant factor
Premium primary classes typically feature a class teacher PLUS a full-time teaching assistant. This effectively halves student-to-adult ratio for many activities (small group reading, math support, etc.). For families paying premium fees, full-time teaching assistant presence is one of the most material differences from mid-tier alternatives. Worth asking explicitly: is there a TA? Is the TA full-time? Across all year groups or only some?
Why class size matters for primary years
Class size matters most for primary years (ages 4-11) where individual attention drives reading, math fluency and social skill development. Premium small classes plus TA support enables differentiated instruction (high-achieving students extended, struggling students supported) within mainstream classroom. Larger classes (28+) can deliver competent education but typically with less differentiation and individualised attention.
Why class size matters less in sixth-form
Sixth-form (IB, A-Level, AP) classes are typically smaller across all tiers because students specialise: only 8-15 students take a particular A-Level Physics class even at large schools. Premium sixth-form class sizes (12-18) and budget sixth-form class sizes (16-25) are less divergent than primary years. The IB Diploma class structure naturally constrains sizes through subject specialisation.
Local-curriculum public schools. different dynamics
NZ state schools (Auckland Grammar, Mount Albert) typically run 25-30 per class; UK state schools 28-32; Australian state schools 25-30. Bavarian state Gymnasium 25-30. Singapore state schools 30-40. These class sizes are larger than premium internationals but smaller than budget international tier. and at zero-to-modest cost for residents.
Asking the right questions
Worth asking specifically: What is current actual class size in [year level] for the upcoming academic year? Are class sizes capped, or do they expand if demand increases? Is there a teaching assistant? Full-time or part-time? What's the staff turnover rate? How are class allocations made for siblings or splits? Are there ability streams or mixed ability classes?