Free calculators
Engineering calculators and diagnostics
15 calculators for cloud, AI, engineering, cost and product decisions. They run in your browser, show the method and sources behind every number, and are free to use, cite and embed.
Every calculator includes
Numbers you can check
- The method, step by step
- Every default assumption, with its source
- What the model leaves out
- The date it was last reviewed
- Code to embed it on your own site
Results are estimates from the inputs and assumptions shown, not quotes or forecasts.
Cloud
3 calculatorsAWS cost savings calculator
Enter your monthly AWS bill and how it splits. The calculator applies five savings levers in order (rightsizing, Spot, Savings Plans, gp2 to gp3 and gateway endpoints) and shows the saving from each, a likely range and what it leaves out.
Reviewed OpenSOC 2 readiness self-assessment
Rate 20 example controls mapped to the AICPA Common Criteria, plus a few for each optional category you put in scope. See a score for each criteria family, a readiness band, a gap list with access, operations and change gaps first, and a timeline for a Type 1 or Type 2 report.
Reviewed OpenCloud migration cost and payback estimator
Sort your workloads by the 7 Rs migration strategies, enter the effort and your team's weekly cost, then the hosting cost before and after. The estimator adds up the one-time cost, including dual running, and shows the timeline and how many months of saving repay it.
Reviewed Open
AI
2 calculatorsAI token cost calculator
Enter requests per day and tokens per request, then compare up to four current models from Anthropic, OpenAI and Google, plus a custom price. It shows monthly, per-1,000-request and yearly cost, the effect of caching and batch, and what the same volume would cost on rented GPUs.
Reviewed OpenRAG feasibility assessment
Answer seven questions about your documents and requirements. The guide lists the pipeline work your project needs, from parsing and chunking to permission filtering, re-ranking and an evaluation plan, and places it in a complexity band from a points table shown in full.
Reviewed Open
Engineering
7 calculatorsTechnical debt scorecard
Answer 10 questions, two each on delivery, testing, data, security and knowledge. Each answer scores 0 to 3, giving a score out of 30, a band from critical to healthy, and the three weakest areas with a next step for each.
Reviewed OpenCore Web Vitals business impact calculator
Enter your field Core Web Vitals and your site's traffic, conversion rate, order value and margin. The calculator rates each metric against Google's thresholds, then shows what a conversion lift you choose would add in revenue and profit, how long the project takes to pay back, and the lift it needs to pay back within a year.
Reviewed OpenPostgreSQL connection and capacity check
Enter peak reads and writes, query time, your server and how the application connects. The check shows connection headroom, queries in flight (Little's law), a starting pool size, whether the hot working set fits in memory, and how an app cache changes database reads.
Reviewed OpenMicroservices readiness assessment
Answer thirteen questions about team size, release independence, delivery, observability and data. The assessment scores Need and Readiness out of 100, caps Readiness when core practices are missing, flags distributed-monolith risk and recommends a monolith, a modular monolith or incremental extraction.
Reviewed OpenDORA metrics benchmark
Answer the four software delivery questions from the DORA survey: deployment frequency, change lead time, change fail rate and recovery time. See which of DORA's four performance levels each answer is nearest, how 2025 respondents answered, and which metric to start with.
Reviewed OpenWorking-hours overlap planner
Pick your time zone and working day, then the other team's. The planner converts both to UTC for the date you choose, daylight saving included, and shows the hours you share, when they fall in each local time, and what moving the other team's day later would change.
Reviewed OpenAPI rate-limit and caching capacity planner
Enter your peak traffic, cacheable share, hit ratio and rate-limit policy. The planner shows the load left on your origin, the Redis throughput and shards you need, cache and limiter memory, and how one client is treated under fixed window, sliding window or token bucket limits.
Reviewed Open
Finance
2 calculatorsSoftware development budget calculator
Enter optimistic, most likely and pessimistic delivery weeks and the team you plan to use, with your own weekly rates. The calculator gives the PERT mean, an 80% estimate and the budget for each, plus the range McConnell's cone of uncertainty puts around an estimate at your project's stage.
Reviewed OpenIn-house vs contracted team cost calculator
Enter what an in-house engineer would cost you and a real quote for a contracted engineer. The calculator costs both over 12, 24 or 36 months, counts hiring time, ramp-up and replacements on each side, and shows the cost per productive engineer-month and the contracted price at which both cost the same.
Reviewed Open
Product
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