# Sandbox resources and pricing | Modal Docs

- **URL:** https://modal.com/docs/guide/sandbox-resources
- **Summary:** Configure CPU, memory, and other resources for Modal Sandboxes. Modal's usage based pricing and ability to burst beyond requests enable cost-efficient resource allocation.

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Sandbox resources and pricing
=============================

This page covers resource configuration and pricing for Modal Sandboxes. For general documentation on CPU and memory options, see [Reserving CPU and memory](https://modal.com/docs/guide/resources)
.

Pay for what you use 

Modal Sandboxes are billed by the second based on whichever is higher: your resource request or your actual usage.

Sandboxes can burst beyond their CPU and memory requests when additional resources are available on the underlying host. Your request guarantees a minimum level of resources, but when spare capacity exists, your Sandbox can use more. You pay for `max(request, actual)`.

See [Billing](https://modal.com/docs/guide/resources#billing)
 in the resource guide for more details.

Configuring resources 

Set CPU and memory requests using the `cpu` and `memory` parameters when creating your Sandbox. The `cpu` parameter specifies physical CPU cores (1 core = 2 vCPUs), and `memory` specifies MiB:

PythonJavaScriptGo

    import modal
    
    app = modal.App.lookup("my-app", create_if_missing=True)
    
    sb = modal.Sandbox.create(
        cpu=0.5,
        memory=512,
        app=app,
    )

    import { ModalClient } from "modal";
    
    const modal = new ModalClient();
    const app = await modal.apps.fromName("my-app", { createIfMissing: true });
    const image = modal.images.fromRegistry("python:3.13-slim");
    
    const sb = await modal.sandboxes.create(app, image, {
      cpu: 0.5,
      memoryMiB: 512,
    });

    package main
    
    import (
    	"context"
    
    	modal "github.com/modal-labs/modal-client/go"
    )
    
    func main() {
    	ctx := context.Background()
    	mc, _ := modal.NewClient()
    
    	app, _ := mc.Apps.FromName(ctx, "my-app", &modal.AppFromNameParams{
    		CreateIfMissing: true,
    	})
    	image := mc.Images.FromRegistry("python:3.13-slim", nil)
    
    	sb, _ := mc.Sandboxes.Create(ctx, app, image, &modal.SandboxCreateParams{
    		CPU:       0.5,
    		MemoryMiB: 512,
    	})
    }

For details on default values and maximum limits, see [Reserving CPU and memory](https://modal.com/docs/guide/resources)
.

### Resource limits 

You can set upper limits to cap how much a Sandbox can burst. This is particularly useful when an AI agent controls what runs inside the Sandbox, as it prevents misbehaving or adversarial workloads from consuming unbounded resources:

PythonJavaScriptGo

    sb = modal.Sandbox.create(
        cpu=(0.5, 4.0),       # Request 0.5 cores, limit to 4 cores
        memory=(512, 2048),   # Request 512 MiB, limit to 2048 MiB
        app=app,
    )

    const sb = await modal.sandboxes.create(app, image, {
      cpu: 0.5,
      cpuLimit: 4.0,
      memoryMiB: 512,
      memoryLimitMiB: 2048,
    });

    sb, _ := mc.Sandboxes.Create(ctx, app, image, &modal.SandboxCreateParams{
    	CPU:            0.5,    // Request 0.5 cores
    	CPULimit:       4.0,    // Limit to 4 cores
    	MemoryMiB:      512,    // Request 512 MiB
    	MemoryLimitMiB: 2048,   // Limit to 2048 MiB
    })

See [Resource limits](https://modal.com/docs/guide/resources#resource-limits)
 for details on how CPU and memory limits behave.

Tuning your requests 

For maximum cost-efficiency, base your requests on observed usage percentiles rather than peaks: around p50–75 for CPU and p90–95 for memory.

If your observed usage is consistently higher than your request, you may run into resource contention on the host. This can manifest as OOM errors or CPU throttling.

The goal should be to set requests that correspond to your base load while letting bursting handle occasional spikes.

1.  Start with default values for CPU and memory.
    
2.  Run your typical workload and observe actual resource usage in the [Modal dashboard](https://modal.com/apps)
     to understand your baseline needs.
    
3.  Set your request to match the resource level your workload consistently needs.
    

GPU Sandboxes 

You can also run Sandboxes with GPUs. See [GPU acceleration](https://modal.com/docs/guide/gpu)
 for available GPU types and configuration.

Unlike CPU Sandboxes, GPU Sandboxes are subject to [preemption](https://modal.com/docs/guide/preemption)
. Design your GPU workloads to handle interruptions gracefully.

Additional resources 

*   [Sandbox pricing](https://modal.com/pricing#sandboxes)
    : current pricing for Sandboxes
*   [Reserving CPU and memory](https://modal.com/docs/guide/resources)
    : CPU, memory, and disk configuration
*   [Billing](https://modal.com/docs/guide/billing)
    : billing cycles, budgets, and cost attribution

[Sandbox resources and pricing](https://modal.com/docs/guide/sandbox-resources#sandbox-resources-and-pricing)
[Pay for what you use](https://modal.com/docs/guide/sandbox-resources#pay-for-what-you-use)
[Configuring resources](https://modal.com/docs/guide/sandbox-resources#configuring-resources)
[Resource limits](https://modal.com/docs/guide/sandbox-resources#resource-limits)
[Tuning your requests](https://modal.com/docs/guide/sandbox-resources#tuning-your-requests)
[GPU Sandboxes](https://modal.com/docs/guide/sandbox-resources#gpu-sandboxes)
[Additional resources](https://modal.com/docs/guide/sandbox-resources#additional-resources)

See it in action

[Reserving CPU and memory](https://modal.com/docs/guide/resources)

[Sandboxes overview](https://modal.com/docs/guide/sandboxes)

[Sandbox pricing](https://modal.com/pricing#sandboxes)