Modal pricing calculator: what your sandboxes cost, and on Runtime

Modal bills sandboxes $0.1419 per physical core-hour (two vCPUs) and $0.0240 per GiB-hour, on the higher of what was requested or used.

Runtime costs 84% less than Modal 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 $396.60 on Modal, $332.71 less. Runtime needs no CPU request sized in advance: it bills what your code uses. Rates checked 23 September 2026.

How Modal bills

Modal publishes per-second rates. A sandbox is billed for whichever is higher, the CPU and memory it requested or what it used, so a requested core is billed while it waits. Modal counts CPU in physical cores, and one physical core is two vCPUs.

Meter	Modal, as published	Converted
CPU	$0.00003942 per physical core-second	× 3,600 = $0.1419 per core-hour, $0.0710 per vCPU-hour
Memory	$0.00000667 per GiB-second	× 3,600 = $0.0240 per GiB-hour

For 2 vCPUs (one core) and 4 GiB that is $0.1419 + $0.0960 = $0.2380 an hour, busy or not. Runtime charges $0.025 per vCPU-hour of measured CPU, floor a twentieth of a vCPU, and $0.0075 per reserved GiB-hour: $0.03125 an hour waiting and $0.08 an hour fully busy.

Example workloads

A month of each, CPU and memory only, from the calculator above.

Workload	Runtime	Modal
Agent runs: 2 vCPU, 4 GiB, 60 s, 20 CPU-seconds, 100,000 a month	$63.89	$396.60
Every CPU busy: 2 vCPU, 4 GiB, 60 s, 120 CPU-seconds, 100,000	$133.33	$396.60
Chat code sessions: 2 vCPU, 4 GiB, 5 min, 30 CPU-seconds, 20,000	$54.17	$396.60
Data analysis: 4 vCPU, 16 GiB, 60 min, 2,880 CPU-seconds, 2,000	$280.00	$1,336.03

The chat-session row shows the difference most clearly: five-minute sessions that use 30 CPU-seconds each cost Modal the same as one-minute runs, because it bills the request for the whole session. On Runtime they cost $54.17, 86% less. With every CPU busy, Runtime still saves 66%.

A smaller CPU request lowers Modal's figure, but it also caps what the sandbox can use when it needs more. Runtime has no request to trade off: a sandbox can use every vCPU it has and pays only for what it used.

Modal sandboxes run for up to 24 hours, with snapshots to carry state beyond that. A Runtime sandbox runs on leases of up to an hour, extended as often as needed, so a long session is priced the same way as a short one: by the CPU it used and the memory it reserved.

What the calculator leaves out

• Plan fees. Modal's Starter plan is $0 and includes $30 of compute a month; the Team plan is $250 a month. Runtime has no plan, only prepaid credit from $10.
• Free credit. The calculator does not subtract Modal's $30 a month of Starter compute; it prices list rates. Runtime starts with 50 sandbox hours on the free trial, no card.
• Storage and network. Left out on both sides. A paused Runtime sandbox keeps its files, memory and running processes for $0.08 per GB a month.

Price your own runs exactly

The CLI prices the sandboxes you have run on Runtime at Modal's published rates, the same vCPUs, memory and running time:

Terminalruntime compare --from modal

It reads the last 30 days of settled sandboxes (--days up to 90) and says what you save a month. Switching from Modal? Record it with runtime switch --from modal before your first top-up, and that top-up is matched, up to $100 (switching credit).

The rest of the comparison, isolation included (Modal uses gVisor; Runtime a microVM with its own kernel), is in Runtime vs Modal. Modal alternatives, E2B vs Modal and Modal vs Vercel Sandbox compare it with the others.

Sources

• Modal pricing, checked 23 September 2026
• Modal resources and billing
• Runtime pricing

Rival rates on this page were checked on 23 September 2026.