Simmodlr is a free, browser-based discrete-event simulation tool. Model queues, resources, and service processes — no install, no code, results you can rely on.
Free · No install · Runs entirely in your browser · simmodlr.app
Queueing formulas assume steady-state averages. Real systems don't work that way — and the gap between the formula and reality grows fast as utilisation rises.
A server at 90% utilisation has roughly nine times more wait time than one at 50% — not 80% more. The formula gives you the wrong number by a wide margin.
Exponential service times and empirical service times produce different queue dynamics. Point estimates hide variance. Confidence intervals reveal it.
When stages share resources, blocking and starvation emerge that no formula predicts. Simulation models these interactions event by event.
No software to install. No data to upload. The simulation engine runs entirely in your browser — open a tab and start modelling.
Define arrivals, queues, activities, and resources using structured editors or the Visual Designer canvas. Describe a scenario in plain text and let the AI generate a starting model.
Run a single simulation or a replicated experiment. Set warm-up periods, termination conditions, and replication counts. Parallel Web Workers run replications simultaneously across your CPU cores.
Confidence intervals, utilisation breakdowns, and run comparisons are generated automatically. The AI Insights panel reads your actual results and produces narrative interpretation and specific recommendations.
Three stages, fully integrated. Build your model, run the experiment, understand the results — all in one place, all in your browser.
Describe your system in plain English and let the AI build a starting model for you — then refine it visually on the drag-and-drop canvas, or through the structured editors. No modelling experience required to get started. No coding required at any point.
Run a single simulation or a full replicated experiment. The engine is proven and handles real-world complexity correctly — results you can rely on, not just plausible-looking numbers.
Confidence intervals, not just averages. The AI reads your actual results and tells you what they mean — what's working, what isn't, and what to try next.
An emergency department receives patients at an average rate of 12 per hour. High-acuity patients (30%) go directly to a priority queue; low-acuity patients (70%) route to a secondary queue.
With 3 clinicians shared across both queues, the department runs at approximately 87% utilisation. The spreadsheet estimate says mean wait is around 14 minutes.
Running 30 replications with warm-up removal, the simulation tells a different story — and the AI Insights panel identifies the structural problem driving it.
"Low-acuity wait variance is high — the CI spans 19 minutes. The shared queue is creating instability under load. Recommend modelling a dedicated low-acuity stream before committing to current staffing."
You do not need a background in simulation. You need a real problem and an honest answer.
A decision is coming — a new service, a change in staffing, an investment in capacity. You need numbers you can defend, not a back-of-envelope estimate. Simmodlr gives you a model you can run, tweak, and present — built in hours, not weeks.
Queues are building. Waits are longer than they should be. Something isn't working but it's not obvious where the problem actually is. Simulation lets you see inside the system — test changes safely before touching anything real.
You're studying operations, engineering, or healthcare systems — or teaching it. Commercial simulation tools are expensive and slow to learn. Simmodlr is free, runs in a browser, and doesn't hide how it works.
No account needed to explore. Sign up free to save models and run replicated experiments.
Free · No credit card · Browser-native · simmodlr.app