How to use the GCP Cost Calculator: step-by-step guide for WordPress users

This calculator is designed to provides a quick, editable estimate of common GCP charges. It bundles a simple input form with a dynamic breakdown and two Plotly.js charts: a cost breakdown pie and a monthly vs yearly bar chart. The interface is intentionally lightweight, responsive, and uses a white background to match most content areas.

What the calculator estimates

The tool focuses on core, repeatable costs that affect most cloud budgets:

• vCPU and RAM (per instance, hourly)
• Persistent disk storage (GB / month)
• Network egress (GB / month)
• Optional GKE node runtime
• A single discount field to model committed use or sustained discounts

Unit rates are defined near the top of the script so you can update them to match the latest GCP pricing for your region. Because cloud pricing changes frequently, use this calculator as a planning estimate rather than an exact bill.

How to use the inputs

The form fields are intentionally straightforward:

• Region: select a region to remember which pricing table to apply later (the default code ships with a few region names but unit rates must be edited manually).
• vCPUs and Memory: enter the size of one instance.
• Monthly VM hours: for always-on instances use ~730 hours; for dev/test lower as appropriate.
• Number of instances: useful for scaling an entire fleet.
• Persistent disk: total GB per instance.
• Network egress: monthly GB leaving the cloud (egress charges vary by destination and tier).
• GKE nodes: number of cluster nodes and runtime are included as node-hour costs.
• Commitment discount: apply a percentage to model committed use discounts or other contract savings.

After entering values click Calculate to update the totals and charts. Click Reset to revert inputs to defaults.

Reading the results and charts

At the top of the results pane you’ll see the estimated monthly cost. Below there’s a compact textual breakdown showing VMs, disk, egress, GKE, and discount amounts. The pie chart visualizes the relative share of each line item so you can quickly identify cost drivers. The bar chart compares the monthly estimate with a year projection (monthly × 12), which is helpful for budgeting and forecasting.

Customizing unit rates and logic

The code contains a small PRICES object where hourly and monthly unit rates live. Replace these placeholder numbers with current GCP prices or your negotiated rates:

• vcpu_per_hour and memory_per_gb_hour approximate VM compute.
• disk_per_gb_month models persistent disk.
• egress_per_gb is a simple egress charge—GCP has tiered and destination-based prices which you can encode for more accuracy.
• gke_node_per_hour is a quick way to include node runtime and can be swapped for full node instance pricing if preferred.

For advanced accuracy:

• Add region-based price tables and pick rates based on the selected region.
• Include sustained use discounts or preemptible/spot pricing paths.
• Extend the calculator to include other services (Cloud SQL, BigQuery, Pub/Sub, load balancers) by adding inputs and chart categories.

Why Plotly.js?

Plotly.js produces interactive, accessible charts that render in the browser without server-side processing. The built-in hover labels, automatic scaling, and responsive layout make it ideal for embedding inside a WordPress page. The charts aid comprehension and boost engagement (users stay longer when a visual summary matches their inputs).

Best practices for publishing

• Provide a short explanation above the calculator so visitors understand it’s an estimate.
• Keep unit rates updated and show a “last updated” timestamp near the tool.
• Encourage users to contact you for a tailored assessment or to validate pricing against their GCP invoice.
• If you publish multiple calculators (e.g., for different regions), create a short index or selector page to help users find the right tool.

Troubleshooting

If the charts do not render, confirm the Plotly CDN loads correctly and that your theme allows inline scripts. If numbers look off, double-check the PRICES object and the input values (hours, instances). Make incremental changes and validate outputs against a known invoice or the GCP Pricing Calculator for key services.

FAQ

Q: Is this an official Google tool?
A: No. This is a lightweight, user-maintained estimator intended for quick planning and teaching. For authoritative pricing consult Google Cloud’s official pricing pages and the GCP Pricing Calculator.

Q: Can it handle complex discounts and committed use?
A: The current build includes a single discount field. To model complex commitments, add region-specific discount brackets or implement a usage tier table in the script.

Q: Will this produce exact billing numbers?
A: No. This tool provides estimates. Real billing depends on negotiated rates, sustained-use discounts, network tiers, taxes, and additional products.

Q: Can I add more services like Cloud SQL or BigQuery?
A: Yes — extend the inputs, add unit rates, and add chart slices to reflect those services.

Q: Is Plotly free to use?
A: Plotly.js (the open-source JS library used here) is free for web embedding. Plotly’s commercial products have separate licensing.