Cost Model

Pricing of compute leases

Lease pricing is fully deterministic. The cost is computed from the resource dimensions and duration using integer arithmetic with milli-XUSD precision. The ledger validates that every lease block carries the exact cost produced by this formula -- no negotiation, no rounding errors.

#Formula

The cost is calculated in two steps: a per-hour rate in milli-XUSD, then converted to whole XUSD:

text

perHourMilli = vCPUs x 20 + ceil(memoryMB / 1024) x 10 + diskGB x 1hours        = ceil(duration / 3600)costMilli    = perHourMilli x hourscost         = ceil(costMilli / 1000)     // minimum 1

In Go:

1func LeaseCost(vcpus, memoryMB, diskGB, duration uint64) (uint64, error) {2    hours := (duration + 3599) / 36003    memGB := (memoryMB + 1023) / 10244    perHourMilli := vcpus*LeaseVCPURate + memGB*LeaseMemGBRate + diskGB*LeaseDiskGBRate5    costMilli := perHourMilli * hours  // overflow-checked via safeMul6    cost := (costMilli + 999) / 1000   // ceiling divide7    if cost == 0 { cost = 1 }8    return cost, nil9}

#Rate table

Resource	Rate	Unit
vCPU	20 milli-XUSD	per vCPU per hour
Memory	10 milli-XUSD	per GB per hour (rounded up to nearest GB)
Disk	1 milli-XUSD	per GB per hour

#Derived values

Value	Formula	Description
Cost	See above	XUSD debited from consumer
Stake	`cost / 5` (min 1)	XUSD locked by provider as collateral
XE Reward	Same as cost formula	XE emitted to provider on settlement

The stake uses integer division: a cost of 7 yields a stake of 1 (7/5 = 1 in integer arithmetic). The minimum stake is 1 XUSD regardless of cost.

#Constants

text

const (    LeaseVCPURate     = 20       // milli-XUSD per vCPU per hour    LeaseMemGBRate    = 10       // milli-XUSD per GB memory per hour    LeaseDiskGBRate   = 1        // milli-XUSD per GB disk per hour    LeaseStakeDivisor = 5        // stake = cost / 5    LeaseMinDuration  = 60       // minimum 1 minute    LeaseMaxDuration  = 31536000 // maximum 365 days)

#Examples

vCPUs	Memory	Disk	Duration	Per-Hr Milli	Hours	Cost Milli	Cost (XUSD)	Stake
1	1024 MB	1 GB	60s	20+10+1=31	1	31	1	1
1	512 MB	5 GB	120s	20+10+5=35	1	35	1	1
2	2048 MB	20 GB	3600s	40+20+20=80	1	80	1	1
4	8192 MB	100 GB	3600s	80+80+100=260	1	260	1	1
2	4096 MB	50 GB	86400s	40+40+50=130	24	3120	4	1
8	16384 MB	200 GB	86400s	160+160+200=520	24	12480	13	2
4	8192 MB	100 GB	2592000s	80+80+100=260	720	187200	188	37

ExampleWorked example: 2 vCPUs, 4 GB RAM, 50 GB disk for 24 hours

diagram

Per-hour milli = (2 x 20) + ceil(4096/1024) x 10 + 50 x 1               = 40 + 40 + 50               = 130 milli-XUSD/hour Hours          = ceil(86400 / 3600) = 24 Cost milli     = 130 x 24 = 3120 Cost           = ceil(3120 / 1000) = 4 XUSDStake          = 4 / 5 = 0 → min 1 = 1 XUSDXE Reward      = 4 XE (on settlement)

#Validation

The ledger enforces the following invariants:

Check	Rule
Cost matches formula	`block.Amount == LeaseCost(vcpus, memoryMB, diskGB, duration)`
Stake matches formula	`lease_accept.Amount == cost / LeaseStakeDivisor` (min 1)
XE reward matches formula	`lease_settle.Amount == LeaseCost(vcpus, memoryMB, diskGB, duration)`
Duration in range	`60 <= duration <= 31,536,000` seconds
Resources non-zero	At least one resource dimension must be > 0
No overflow	Multiplication uses `safeMul()` with overflow detection via `bits.Mul64`
Integer arithmetic	All calculations use `uint64` -- no floating point