Variable Cost per Active License
What one actively used license costs per month: variable cost ÷ active licenses. Fixed costs are shown separately; teachers pay nothing (teacher-access cost stays on the Costs page); engineering tools and non-production are overhead.
How an active license is counted
An active license is a distinct student, with or without an account, on a licensed campus, who had actual usage in that month:
- 1
Usage that month only
Every graded result created in the calendar month (UTC) — scanned or online. Nothing carries over from earlier months.
- 2
Real activities only
An activity counts only if it received 10+ results that month; smaller ones (tests, dummies) are dropped.
- 3
Who the student is
Their account; otherwise the class-list entry (student number, else name); otherwise the name on the scanned sheet. Sheets with no name and no class-list entry are left out.
- 4
Licensed campus
The student's campus (or, without an account, the class teacher's) had a campus license live during the month. Pilot licenses count; DepEd partner universities (GradeChum in a Box) are excluded.
- 5
Each person once
Multi-page sheets, re-scans and students in several classes collapse to one. Class-list numbers and unique names on the campus merge into the matching account.
- 6
No dummies
Accounts on @codechum.com / @gradechum.com and test names (test, dummy, sample, demo, fake, qa, “Student 1”…) are excluded.
Name-only matches are the weakest identity — a misread name on a sheet can count one student twice.
$0.131
43,199 active licenses · 2026-10
▼ 24.6% vs 2026-09$5,648.33
2026-10 · 79% of user-serving
▲ 8.8% vs 2026-09$1,512.34
2026-10 · $0.035 / active license at this usage
▲ 4.3% vs 2026-09$1,228.28
Variable $339 · fixed $889 · on pace for ~$9,212
▲ 132.1% GCP vs same days last monthClick a month to open its line items below.
| Month | Active licenses | Variable | Fixed | Variable / license | All-in / license | Overhead | Total |
|---|---|---|---|---|---|---|---|
| 2026-11 month-to-date No note | 10,790 | $339.05 | $889.23 | $0.031 | $0.114 | $71.08 | $1,299.36 |
| 2026-10 No note | 43,199 | $5,648.33 | $1,512.34 | $0.131 | $0.166 | $499.69 | $7,660.36 |
| 2026-09 School year in full swing: active licenses jumped with the new term. Gemini 3.7 Flash is now the largest AI cost line. | 29,917 | $5,191.08 | $1,449.89 | $0.174 | $0.222 | $789.76 | $7,430.73 |
| 2026-08 Sem 1 starts; first month without the GCP promo credit. Variable cost is inflated by the processor idle-wait bug (~$1,355 on Aug 30–31 alone). | 11,254 | $3,968.43 | $1,365.53 | $0.353 | $0.474 | $809.85 | $6,143.81 |
| 2026-07 Last month covered by the GCP promotional credit (it ran out Aug 1–2); costs shown are before that credit. | 7,227 | $2,411.98 | $1,250.17 | $0.334 | $0.507 | $705.70 | $4,367.85 |
| 2026-06 Summer — low usage. GCP promo credit still covered the bill; costs shown are before that credit. No R2 usage split for this month (Cloudflare keeps ~13 weeks of analytics), so production R2 sits in the invoice remainder under overhead. | 6,845 | $1,221.44 | $1,206.14 | $0.178 | $0.355 | $633.61 | $3,061.19 |
| 2026-05 No note | 16,222 | $3,418.36 | $1,155.55 | $0.211 | $0.282 | $863.15 | $5,437.06 |
| 2026-04 No note | 18,043 | $3,227.26 | $1,181.87 | $0.179 | $0.244 | $2,843.20 | $7,252.33 |
| 2026-03AI estimated · no GCP infra No note | 17,182 | $3,064.01 | $991.80 | $0.178 | $0.236 | $415.08 | $4,470.89 |
| 2026-02AI estimated · no GCP infra No note | 13,587 | $1,597.94 | $867.48 | $0.118 | $0.181 | $726.93 | $3,192.35 |
| 2026-01AI estimated · no GCP infra No note | 1,841 | $514.28 | $814.08 | $0.279 | $0.722 | $779.39 | $2,107.75 |
| 2025-12AI estimated · no GCP infra No note | 8,306 | $944.44 | $836.34 | $0.114 | $0.214 | $78.50 | $1,859.28 |
| 2025-11AI estimated · no GCP infra No note | 9,047 | $1,525.88 | $825.07 | $0.169 | $0.260 | $33.47 | $2,384.42 |
| 2025-10AI estimated · no GCP infra No note | 10,075 | $641.09 | $830.85 | $0.064 | $0.146 | $72.28 | $1,544.22 |
Each student counts once, under the campus where most of their results are, so the counted rows add up to the month's active licenses. DepEd partner universities are shown but excluded; pilots are included. Est. variable cost = licenses × $0.178.
| University | Active licenses | Share | Est. variable cost |
|---|---|---|---|
| Cebu Institute of Technology - UniversityMain Campus | 4,227 | 61.8% | $754.28 |
| Mapua UniversityManila Campus | 944 | 13.8% | $168.45 |
| Our Lady of Fatima UniversityValenzuela Campus | 616 | 9.0% | $109.92 |
| Free UniversityMain Campus | 540 | 7.9% | $96.36 |
| Mapua Malayan Colleges LagunaMain Campus | 236 | 3.4% | $42.11 |
| St. Therese Private SchoolMain Campus | 158 | 2.3% | $28.19 |
| Mapua Malayan Colleges of MindanaoMain Campus | 74 | 1.1% | $13.20 |
| CodeChum AcademyMain Campus | 32 | 0.5% | $5.71 |
| ChumLabs AcademyW/ License Campus | 18 | 0.3% | $3.21 |
| Luray II National High SchoolDepEd · excludedMain Campus | 538 | excluded | — |
| DEPED Free UniversityDepEd · excludedMain Campus | 68 | excluded | — |
| Total · 9 universitiesexcludes 606 DepEd | 6,845 | $1,221.44 |
Variable and all-in apply the month's platform-wide cost per active license to this university's active licenses. Measured AI is this university's own AI usage: Langfuse production cost by teacher → campus (or email domain) → university, scaled to the billed AI line; unmatched traces are spread pro rata. Use variable cost to project added cost for a new school; fixed costs don't grow with one more school.
| Month | Active licenses | Variable cost | Variable / license | All-in cost | Measured AI | Measured AI / license |
|---|---|---|---|---|---|---|
| 2026-11 month-to-date | 6,123 | $192.40 | $0.031 | $697.01 | $65.40 | $0.011 |
| 2026-10 | 20,108 | $2,629.15 | $0.131 | $3,333.10 | $1,940.23 | $0.096 |
| 2026-09 | 17,887 | $3,103.68 | $0.174 | $3,970.55 | $2,751.20 | $0.154 |
| 2026-08 | 8,326 | $2,935.95 | $0.353 | $3,946.20 | $588.46 | $0.071 |
| 2026-07 | 3,337 | $1,113.71 | $0.334 | $1,690.96 | $1,136.92 | $0.341 |
| 2026-06 | 4,227 | $754.28 | $0.178 | $1,499.11 | $360.54 | $0.085 |
| 2026-05 | 12,630 | $2,661.44 | $0.211 | $3,561.12 | $2,041.10 | $0.162 |
| 2026-04 | 11,676 | $2,088.43 | $0.179 | $2,853.24 | $2,545.09 | $0.218 |
| 2026-03AI estimated | 13,157 | $2,346.24 | $0.178 | $3,105.71 | $2,034.73 | $0.155 |
| 2026-02AI estimated | 10,898 | $1,281.69 | $0.118 | $1,977.49 | $1,165.11 | $0.107 |
| 2026-01AI estimated | 470 | $131.29 | $0.279 | $339.13 | $4.23 | $0.009 |
| 2025-12AI estimated | 7,160 | $814.13 | $0.114 | $1,535.08 | $584.10 | $0.082 |
| 2025-11AI estimated | 5,745 | $968.96 | $0.169 | $1,492.89 | $329.05 | $0.057 |
| 2025-10AI estimated | 7,077 | $450.32 | $0.064 | $1,033.94 | $485.70 | $0.069 |
| Average · 13 complete months | 9,438 | $0.173 | $0.247 / license | $0.130 |
Averages are per active license, weighted by licenses, over complete months (month to date left out). Months marked AI estimated predate the GCP billing export (Mar 2026): their GCP infrastructure isn't counted and Vertex AI is Langfuse traced cost × 1.26, so their all-in cost is understated.
Summer — low usage. GCP promo credit still covered the bill; costs shown are before that credit. No R2 usage split for this month (Cloudflare keeps ~13 weeks of analytics), so production R2 sits in the invoice remainder under overhead.
Vertex AI2 lines$1,170.66
- $901.43grading (production)Variable
Langfuse: 77.0% of traced AI cost is production
- $269.23evals, staging & localOverhead
Langfuse: 77.0% of traced AI cost is production
Cloud Run21 lines$352.53
- $142.37gradechum-api-productionVariable
- $98.66gradechum-overall-processorVariable
- $59.59gradechum-api-canaryVariable
- $20.89gradechum-api-stagingOverhead
- $8.21gradechum-overall-processor-stagingOverhead
- $4.42gradechum-api-feature-cOverhead
- $3.63questionnaire-to-gradechum-v3Variable
- $3.13gradechum-api-feature-aOverhead
- $2.74gradechum-files-com-webhookFixedalways-on
- $2.64gradechum-api-feature-bOverhead
- $2.13gradechum-answersheet-downloadVariable
- $1.67questionnaire-pdf-generator-v2Variable
Compute Engine16 lines$268.46
- $63.83gradechum-internal-analyticsOverhead
- $58.12gradechum-kiosks-managerFixed
- $51.56gradechum-kiosk-netbirdFixed
- $28.45Serverless VPC connectorsFixed
- $19.99vpn-proxyOverhead
- $18.51gradechum-server-statuschecksOverhead
- $8.10gradechum-e2e-serverOverhead
- $6.74gradechum-e2e-static-ipOverhead
- $6.03gradechum-kiosks-manager-ipFixed
- $2.17snapshots of gradechum-internal*Overhead
- $2.12snapshots of gradechum-server-st*Overhead
- $1.84snapshots of gradechum-e2e-serve*Overhead
Sentry1 line$250.00
- $250.00Error monitoring planFixed
Flat $250/month (user, 2026-09-25) — monitors the production API, processor and mobile app
Langfuse1 line$232.29
- $232.29AI tracing planFixed
Invoice 2026-06-09: $232.29
Files.com1 line$199.00
- $199.00Scan intake planFixed
Assumed flat $199/month
Neon2 lines$184.58
- $135.36Production DB, job queue & webhook stateFixed
Neon consumption history × Launch prices · fixed: mostly the always-on compute floor
- $49.22Internal dashboards, dev & other productsOverhead
Neon consumption history × Launch prices · fixed: mostly the always-on compute floor · 14 projects
Cloudflare3 lines$160.41
- $100.41Rest of invoice (R2 + Argo/Workers usage, not split)Overhead
Invoice 2026-06-12: $195.41 total · R2 analytics no longer retained, so usage can't be split by product
- $35.00gradechum.com plan & certificatesFixed
Current subscription list price
- $25.00Other zones (chumlabs.co)Overhead
Current subscription list price
Postmark1 line$60.00
- $60.00Transactional emailFixed
Assumed flat $60/month
Networking2 lines$53.13
- $52.32NAT, load balancer & ArmorFixed
Cloud Memorystore for Redis1 line$46.26
- $46.26Cloud Memorystore for RedisFixed
Artifact Registry1 line$38.96
- $38.96Artifact RegistryFixed
Gemini API (API key)1 line$24.54
- $24.54Gemini API (API key)Overhead
Cloud Storage1 line$9.45
- $9.45Cloud StorageVariable
Secret Manager1 line$6.28
- $6.28Secret ManagerFixed
Cloud DNS1 line$1.22
- $1.22Cloud DNSFixed
Cloud Scheduler1 line$1.01
- $1.01Cloud SchedulerFixed
Cloud Monitoring1 line$0.91
Cloud Logging1 line$0.85
BigQuery1 line$0.43
Cloud Vision API1 line$0.21
Cloud Pub/Sub1 line$0.01
For vendors without an automated feed. GCP (including AI) is synced automatically.