Runtime

Prime Sandboxes pricing calculator: what your sandboxes cost, and on Runtime

Prime Sandboxes bill $0.02 per vCPU-hour and $0.0125 per GiB-hour of memory while a sandbox runs, busy or idle.

Runtime costs 58% less than Prime Sandboxes for an agent that waits on a model. 100,000 one-minute runs of a 2 vCPU, 4 GiB sandbox, each using 20 CPU-seconds, cost $63.89 a month on Runtime and $151.67 on Prime. Prime's CPU rate is lower than Runtime's, but it is charged for every vCPU the whole time, and its memory costs two thirds more. Rates checked 25 September 2026.

Price your workload

$63.89 a month on Runtime against $151.67 on Prime Sandboxes: 58% less.

ProviderA monthRuntime saves
Runtime$63.89—
Northflank$111.1042%
Cloudflare Sandbox$135.0453%
Fly Machines$143.5055%
Prime Sandboxes$151.6758%
Morph$166.6762%
Vercel Sandbox$212.4470%
Freestyle$224.9972%
CodeSandbox$247.6774%
E2B$276.0077%
Daytona$276.0077%
Blaxel$276.0077%
Fly Sprites$330.5681%
Modal$396.6084%
AWS Lambda MicroVMs$420.3385%
Runloop$532.5688%

CPU and memory at published list rates, checked 23 September 2026 to 25 September 2026. Plan fees, storage, network and free credits are left out.

How Prime Sandboxes bill

A Prime sandbox is billed while it runs, for the CPU, memory and disk it was given. Its defaults are 1 vCPU, 1 GiB and 5 GiB of disk, and it can grow to 16 vCPUs, 64 GiB and 128 GiB of disk.

Meter Prime, as published For 2 vCPUs, 4 GiB and 5 GiB of disk Runtime
CPU $0.02 per vCPU per hour $0.04 an hour $0.025 per vCPU-hour of CPU actually used
Memory $0.0125 per GiB per hour $0.05 an hour $0.0075 per reserved GiB-hour
Disk $0.0002 per GiB per hour $0.001 an hour Included while it runs

So the shape is $0.091 an hour on Prime, working or waiting. On Runtime it is $0.03125 an hour while it waits and $0.08 with both CPUs busy, so Runtime costs less at every level of use. The calculator keeps Prime's 5 GiB default disk for every shape.

Example workloads

A month of each, from the calculator above.

Workload Runtime Prime Sandboxes
Agent runs: 2 vCPU, 4 GiB, 60 s, 20 CPU-seconds, 100,000 a month $63.89 $151.67
Waiting agents: 2 vCPU, 4 GiB, 30 min, 180 CPU-seconds, 10,000 $162.50 $455.00
Tool calls: 1 vCPU, 2 GiB, 2 min, 30 CPU-seconds, 50,000 $35.42 $76.67
Every CPU busy: 2 vCPU, 4 GiB, 60 s, 120 CPU-seconds, 100,000 $133.33 $151.67

The first three rows save 54% to 64%. The last is the closest Prime comes: with the CPUs never resting, Runtime is 12% cheaper.

Rollouts that wait on a model

Prime built its sandboxes for agentic reinforcement learning, where thousands of rollouts each run a few tool calls between long waits for the policy model. That is the shape where measured CPU pays most: a rollout that computes for 20 seconds of every minute costs less than half as much on Runtime as on Prime. Runtime's forks help the same work, since one set-up environment becomes up to 10 running copies with memory included; Prime lists snapshots and forks as coming soon.

What the calculator leaves out

  • The end of launch pricing. Prime publishes these rates through 22 December 2026. Runtime's rates are fixed in each resource's quote.
  • Free start. Prime publishes none. Runtime gives 100 sandbox hours on the free trial, no card.
  • Network. Left out on both sides.

Price your own runs exactly

After a few runs on Runtime, the CLI prices those same sandboxes at Prime's published rates:

Terminalruntime compare --from prime

It reads your settled sandboxes from the last 30 days (--days up to 90). The full comparison is Runtime vs Prime Sandboxes, agent evals and SWE-bench shows evaluation runs on Runtime, and the sandbox cost calculator prices every provider for your shape.

Sources

Rival rates on this page were checked on 25 September 2026.

Claim 100 hours free