Which maths olympiad for a primary school child? The full map
Eligibility decides most of it. SASMO runs its own paper at every level from P1 to P6 and is the only one a parent can enter privately. NMOS is P5 only and never repeats. APMOPS and RMO are two-round contests that reward a year of training. Start with SASMO alone; add nothing until there is real preparation behind it.
The map, level by level
| Level | Good first contest | Add after a year of training | One shot only |
|---|---|---|---|
| P1 – P3 Lower primary |
SASMO — own paper for each grade. The only contest open at this age. | Nothing else yet. NMOS, APMOPS and RMO all begin at P4 or later. | — |
| P4 First year with a second option |
SASMO — still the natural entry point. | RMO Junior, but only with prior olympiad training. It is the hardest primary paper. | — |
| P5 Every contest open — the busiest year |
SASMO — if this is the first contest, sit only this one. | APMOPS Round 1 (Invitation round is P6 only); RMO Junior with a year of training behind it. | NMOS — P5 only. Sit it this year or not at all. |
| P6 Last year — and a PSLE year |
SASMO — one paper, no second round to plan around. | APMOPS + Invitation (only P6 reaches it: top 50 nationally); RMO Open, two rounds. | — |
Eligibility follows the 2025–2026 cycles — confirm with the organiser before registering.
Who registers matters more than most parents realise
NMOS, APMOPS and RMO are registered through the school. SASMO is the one a parent can enter directly as a private candidate.
This single fact resolves a great many agonised decisions. If your child's school does not register for NMOS, APMOPS or RMO, then those three are simply not on your menu and the choice collapses to one contest. Ask the maths department before you spend a term weighing options that were never available. More on the private-candidate route →
Start with one
A child sitting a first olympiad should sit one paper. Three contests in eight weeks teaches time pressure, not mathematics.
The P5 decision is the only one with a real deadline
NMOS is the only entry on the chart that cannot be deferred. Everything else comes round again next year, which means almost none of the urgency parents feel in P5 is real — except this one. Make that decision deliberately, and let the rest wait.
What we can't know
Eligibility follows recent cycles and organisers do revise it. Nothing here is a substitute for the organiser's own current page, and dates in particular should never be taken from a third party — including us.
Sources
- MathsKid “Which Olympiad Fits My Child” poster (PDF)
- Contest eligibility as published for the 2025–2026 cycles
Last verified: 2026-08-05
Curious where your child actually stands?
A 3-question check, escalating in difficulty, for one grade — no email needed to see the result.