Open SLM Leaderboard

A leaderboard for sub-150M parameter language models, evaluated using LM-eval harness or a custom benchmark script available here ArithMark-3.0.

To support our work and help us keep this leaderboard up to date, please consider giving the space a like and follow!

Notable New Releases

Short notes on new models and leaderboard shifts.

26/08/2026 update
Open SLM UI gets a catalogue refresh

The leaderboard UI now brings filter leaders, animated benchmark expansion, Intelligence Index fit scores, and paged release notes into one clearer workspace.

Leaderboard Update · UI
12/07/2026 change
Leaderboard Math Changes

ArithMark-3 is now the primary math benchmark for ranking, weighting subject to change. ArithMark-2 remains available in the expanded columns.

Leaderboard Change · Math
19/06/2026 new
Axiomic Labs GPT-S2 takes <10M #1 spot

Built on Axiomic Labs' T-X4 refresh-gated XSA stack, GPT-S2-5M pushes into the sub-10M bracket and lands at the top, dethroning SLM-10M.

Axiomic Labs · 5.4M params

Leaderboard

Zero-shot evaluation. Higher is better for all columns. Click any header to sort.

Model size
Compare # Model Params Int Index HellaSwag ARC-Easy ARC-Challenge PIQA ArithMark-3 Avg Fit Std Devs ArithMark-2

Compare

Models you add from the leaderboard line up side by side here. None selected

Up to 6 models at a time

Scores

Top scores for the active size and benchmark filters.

Benchmark

Top Intelligence Index Scores

Efficiency

Score vs parameter count (log scale). Shaded zone = above regression line.

Intelligence Index vs Log Parameters

Org Leaderboard

Average standard deviations above or below the Intelligence Index-vs-size fit line.

# Organization Models Fit Std Devs Mean Int Index Best Model vs Fit

Rules

Eligibility, evaluation, and submission requirements for the Open SLM Leaderboard.

RULE 01

Stay below 150M parameters

The leaderboard is for language models with fewer than 150 million parameters.

RULE 02

Train it from scratch

The submitted model must be pretrained from scratch by you or your organization.

RULE 03

Publish open weights

Model weights must be openly available and point to a genuine training checkpoint, not a merged model.

RULE 04

Use the listed evaluations

Provide zero-shot results for the listed benchmarks using LM-eval harness or the linked custom ArithMark script.

RULE 05

Results are verified

Submitted results are independently checked by the leaderboard team before they are merged.

RULE 06

Submit through the Space

Open a PR or discussion with the benchmark results in the leaderboard Space.

Add your model

Open a PR or discussion on this Space with your model's results for the given benchmarks. They will be independently verified by our team and then your PR will be merged. Your model must be pretrained by you from scratch, open weights and be a training checkpoint (not merged) to qualify Open a PR →

How the Intelligence Index is calculated

Each benchmark is first adjusted for its random-chance floor, so chance performance maps to 0 and perfect performance maps to 100.

N(score, chance) = 100 × (score − chance) ÷ (100 − chance)
Int Index = (HellaSwag + ARC + PIQA + 0.65 × ArithMark-3) ÷ 3.65
HellaSwagweight 1.00
chance 25
Combined ARCweight 1.00
chance 25
PIQAweight 1.00
chance 50
ArithMark-3weight 0.65
chance 25

Combined ARC is the mean of ARC-Easy and ARC-Challenge before normalization. When a component is unavailable, its weight is removed from both the numerator and denominator; at least two components are required. Scores below chance may be negative. ArithMark-2 is displayed separately and is not included in the index.