Direct answer: at the Azure Retail Prices API on 9 November 2026 (eastus, Linux, USD, excluding tax/discounts), Azure App Service bills by “App Service plan × instance count”: B1 $0.017/hour (about $12.41/month), S1 $0.095/hour ($69.35/month), P1v3 $0.113/hour ($82.49/month), P1v4 $0.146/hour ($106.58/month), P2v3 $0.226 ($164.98), P3v3 $0.452 ($329.96). Three instances: B1 $37.23, S1 $208.05, P1v3 $247.47, P1v4 $319.74; ten instances: B1 $124.10, S1 $693.50, P1v3 $824.90, P1v4 $1,065.80. Selection rule: F1/Shared for development only; B1 for test/low traffic; S1+ for deployment slots/autoscale/backups and small production; P1v3/P1v4 for production; Isolated for network isolation/dedicated hardware; Container Apps for containerized microservices; Functions for events/short tasks.
This guide is for Azure application platform, SRE, .NET/PHP/Node developers and FinOps teams. It explains Linux B1/S1/P1v3/P1v4 prices, plan/instance/slot relationships, 1/3/10-instance TCO, the boundary versus Container Apps/Functions/AKS, hidden costs and a 90-day checklist. Prices come from the Azure App Service Linux pricing page and Azure Retail Prices API (eastus, 9 November 2026); plans/slots/features come from Microsoft Learn's hosting plans doc. Official price facts, editorial calculations and exclusions are kept separate. This is not procurement advice.
(1) Billing is at the plan level: one plan × instances; all apps/slots share the VMs, so scaling out adds linearly. (2) Features follow the tier: Standard+ adds deployment slots/autoscale/backups; Premium adds density/larger sizes; do not run production on B1. (3) Do not compare App Service directly with Container Apps/Functions: App Service is always-on PaaS, Container Apps bills vCPU/GiB-seconds, Functions bills executions/GB-seconds.
Plans and tiers: Free/Basic/Standard/Premium/Isolated
Free/Shared run on shared VMs with CPU quotas, development only; Basic is dedicated VMs with no deployment slots/autoscale/backups; Standard+ adds slots, autoscale, backups, custom domains/SSL; Premium v3/v4 offers higher density/larger sizes/more slots; Isolated provides network isolation/dedicated environment (ASE). Linux and Windows plans are priced separately, with Windows usually higher; all apps/slots share plan instances.
| Tier | Compute | Key features | Best for |
|---|---|---|---|
| Free/Shared | Shared VM/CPU quota | Basic hosting | Development/trials |
| Basic B1–B3 | Dedicated VMs | Custom domains/SSL; no slots/autoscale/backups | Test/low traffic |
| Standard S1–S3 | Dedicated VMs | Slots/autoscale/backups | Small production |
| Premium v3/v4 | Higher size/density | More slots/better performance | Production |
| Isolated | Dedicated ASE | Network isolation/dedicated hardware | Compliance/enterprise |
Source: Microsoft Learn, App Service hosting plans (9 November 2026). Editorial summary; specs/features follow official docs.
Unit prices: Linux B1/S1/P1v3/P1v4
Eastus Linux list prices: B1 $0.017/hour, B2 $0.034, B3 $0.067; S1 $0.095, S2 $0.19, S3 $0.38; P1v3 $0.113, P2v3 $0.226, P3v3 $0.452; P1v4 $0.146, P2v4 $0.292, P3v4 $0.584. At 730 hours/month: B1 $12.41, S1 $69.35, P1v3 $82.49, P1v4 $106.58, P2v3 $164.98, P3v3 $329.96. Windows plans are priced separately, usually higher.
| Plan | Price (USD/hour) | Monthly (730h) |
|---|---|---|
| B1 | 0.017 | 12.41 |
| B2 / B3 | 0.034 / 0.067 | 24.82 / 48.91 |
| S1 | 0.095 | 69.35 |
| S2 / S3 | 0.19 / 0.38 | 138.70 / 277.40 |
| P1v3 | 0.113 | 82.49 |
| P2v3 / P3v3 | 0.226 / 0.452 | 164.98 / 329.96 |
| P1v4 | 0.146 | 106.58 |
| P2v4 / P3v4 | 0.292 / 0.584 | 213.16 / 426.32 |
Sources: Azure Retail Prices API (eastus, Linux, 9 November 2026) and App Service Linux pricing page. Monthly prices use 730 hours; tax/discounts/reservations excluded.
TCO: 1 / 3 / 10 instances
App Service plans bill per instance; scaling to 3/10 instances multiplies the monthly fee by 3/10: 1 instance B1 $12.41, S1 $69.35, P1v3 $82.49, P1v4 $106.58; 3 instances $37.23/$208.05/$247.47/$319.74; 10 instances $124.10/$693.50/$824.90/$1,065.80. Multiple apps/slots in the plan share these instances at no extra compute charge (but contend for CPU/memory).
| Plan | 1 instance | 3 instances | 10 instances |
|---|---|---|---|
| B1 | 12.41 | 37.23 | 124.10 |
| S1 | 69.35 | 208.05 | 693.50 |
| P1v3 | 82.49 | 247.47 | 824.90 |
| P1v4 | 106.58 | 319.74 | 1,065.80 |
Editorial calculation: hourly fee ×730 × instances; slots/egress/backups/certificates/tax/discounts excluded; apps/slots share plan instances.
Boundary with Container Apps / Functions / AKS
App Service fits always-on web/API, deployment slots/autoscale/custom domains and teams that prefer not to manage containers; Container Apps fits containerized microservices, bills vCPU/GiB-seconds and can scale to zero; Functions fits event-driven/short tasks, billed per execution/GB-second; AKS fits full Kubernetes/custom controllers. App Service's “always-on” means idle is billed; Container Apps/Functions can be cheaper when scaled to zero.
| Scenario | Prefer | Check first |
|---|---|---|
| Always-on web/API/slots | App Service | Plan/instances/slots/autoscale |
| Containers/microservices/scale to zero | Container Apps | vCPU/GiB-seconds, requests |
| Events/short tasks | Functions | Executions/GB-seconds, cold start |
| Full K8s/custom controllers | AKS | Control plane/nodes/operations |
| Compliance/network isolation | Isolated/ASE | ASE cost/network |
| Development/trials | Free/Shared or B1 | Quota/no slots |
Editorial selection framework, not a vendor recommendation; features/compliance/regional availability follow official docs and business requirements.
Hidden costs: seven items beyond the plan
Common add-ons: instances/autoscale (linear per instance), deployment slots (Standard+; shared plan but consume CPU/memory), backups (Standard+ storage/frequency), egress (cross-region/public), custom domains/certificates (standard SSL free; IP SSL/advanced certs extra), ASE/Isolated (dedicated environment is expensive), logs/App Insights (ingestion/retention) and WebJobs/diagnostic logs (consume plan resources).
| Cost item | Trigger | Control |
|---|---|---|
| Instances/autoscale | Traffic/rules | Headroom for peaks; scale down |
| Deployment slots | Standard+ multiple slots | Use for release process |
| Backups | Standard+ | Frequency/retention by RPO |
| Egress | Cross-region/public | Same region/compression/CDN |
| Certificates/IP SSL | Custom domain/advanced certs | Standard SSL/managed certs |
| ASE/Isolated | Network isolation | Only for compliance needs |
| Logs/WebJobs | Diagnostics/background | Sampling/on demand |
Sources: App Service pricing/hosting plans docs (9 November 2026). Editorial summary; billing follows official pages and bills.
How to choose: dev, production, isolation and containers
Development/trials: Free/Shared or B1; small production: S1 (slots/autoscale/backups); production: P1v3/P1v4 with instances scaled by traffic; network isolation/dedicated hardware: Isolated/ASE; containers/microservices: Container Apps; events/short tasks: Functions. Choose the tier by “always-on/scale-to-zero, slots/autoscale, compliance/isolation,” then calculate monthly cost by instances.
| Scenario | Prefer | Check first |
|---|---|---|
| Development/trials | Free/Shared, B1 | Quota, no slots/autoscale |
| Small production/slots | S1 | Instances, slots, backups |
| Production/higher density | P1v3/P1v4 | Instances, autoscale |
| Network isolation/compliance | Isolated/ASE | ASE cost/network |
| Containers/microservices | Container Apps | vCPU/GiB-seconds, scale to zero |
| Events/short tasks | Functions | Executions/GB-seconds |
Editorial selection framework, not a vendor recommendation; features/compliance/regional availability follow official docs and business requirements.
90-day checklist
Use the first 90 days to close “apps/traffic → plan → instances/slots → pilot → cutover → review.” Weeks 1-2: inventory apps, CPU/memory, peaks, slot/backup needs; weeks 2-4: choose B1/S1/P1v3/P1v4 and instance count; weeks 4-6: deploy a pilot and test autoscale/slot swap; weeks 6-8: configure custom domain/SSL/backups/logs; weeks 8-10: cut over and monitor; weeks 10-12: cost review, tune instances/plan. Do not run production on B1 long term.
FAQ
How is App Service billed?
By App Service plan × instance count; apps/slots share instances. Linux B1 $0.017/h ($12.41/month), S1 $0.095 ($69.35), P1v3 $0.113 ($82.49), P1v4 $0.146 ($106.58).
What is the difference between B1 and S1?
B1 is a low-spec dedicated VM with no slots/autoscale/backups; S1+ adds slots, autoscale and backups, suitable for small production. S1 is about $69.35/month vs B1 $12.41/month.
P1v3 or P1v4?
Both are Premium tier; P1v4 is $0.146/h ($106.58/month) vs P1v3 $0.113/h ($82.49/month), with newer specs/performance. Choose by benchmark and regional availability.
How are extra instances billed?
Linearly: 3 instances = monthly ×3, 10 = ×10. B1 10 instances about $124.10/month; S1 about $693.50; P1v3 about $824.90.
Do deployment slots cost extra?
Slots share plan instances with no extra compute charge, but consume CPU/memory; Standard+ supports slots. Many slots may require a larger plan/more instances.
App Service or Container Apps?
Always-on web/API with slots/autoscale → App Service; containerized/microservices/scale to zero → Container Apps. App Service bills while idle; Container Apps compute is zero at zero replicas.
App Service or Functions?
Event-driven/short tasks → Functions (executions/GB-seconds); always-on web/API → App Service. Functions Flex 1M executions about $10.70/month; App Service S1 about $69.35/month.
How much more is Windows?
Windows and Linux are priced separately and usually higher; this article uses Linux list prices. Check the pricing page/Retail API for Windows.
Research method and limitations
This article separates “official price facts” from “editorial calculations.” Linux B1/B2/B3, S1/S2/S3, P1v3–P3v3 and P1v4–P3v4 hourly prices come from the Azure App Service Linux pricing page and Azure Retail Prices API (eastus, 9 November 2026); tiers/slots/autoscale/backups/Isolated come from Microsoft Learn's hosting plans doc. TCO, hidden costs and the 90-day checklist are editorial.
Eight limitations: (1) only eastus/Linux list prices, excluding Windows/tax/discounts/reservations; (2) 730 hours and 1/3/10 instances; (3) slots/egress/backups/certificates/ASE/logs combinations are excluded; (4) no real autoscale/slot-swap/performance benchmark; (5) App Service Environment/Isolated billing details are not covered; (6) 1/3-year reservation discounts are not modeled (API has reservation meters—verify on the pricing page); (7) all runtimes/regional differences are not covered; (8) prices/features change, so recheck official pages and bills before purchase.
Sources and basis
- Microsoft Azure, App Service Linux Pricing: azure.microsoft.com/en-us/pricing/details/app-service/linux. B1/S1/P1v3/P1v4 and tier prices. Accessed 9 November 2026.
- Azure Retail Prices API (App Service Linux, eastus): prices.azure.com/api/retail/prices. 0.017/0.095/0.113/0.146, S2/S3, P2/P3. Accessed 9 November 2026.
- Microsoft Learn, App Service hosting plans: learn.microsoft.com/azure/app-service/overview-hosting-plans. Tiers/slots/autoscale/backups/Isolated. Accessed 9 November 2026.
Data cut-off 9 November 2026; prices/availability follow the Azure official page and bill; this is not procurement, commercial or legal advice.