IT & Tech
IT teams are increasingly asked to justify decisions in numbers: what an outage costs, how much capacity is enough, whether a security control pays for itself. These courses teach those calculations in a spreadsheet you build yourself, with each step checked, so your estimates stand up when finance or management asks how you got there.
The 29 courses include cybersecurity risk quantification, cloud cost management, service levels and reliability, DevOps and QA metrics, capacity planning for servers, databases, containers and networks, storage and backup, IP subnetting, web performance, CDN economics, API quotas, software licences and asset refresh cycles. There is also a course on SQL concepts using spreadsheets.
IT & TechPut dollars on cyber risk: SLE, ARO and ALE, control cost-benefit, risk matrix and register, PERT loss ranges, vulnerability SLAs, phishing and incident metrics, on live auto-graded spreadsheets.
IT & TechBreak down the cloud bill, track unit costs, find the commitment break-even, rightsize, tier storage, allocate shared costs, forecast to month end and catch cost spikes, on live auto-graded spreadsheets.
IT & TechAvailability and the nines, MTBF/MTTR, SLA compliance, backlog and FCR, error budgets, capacity planning, change success and service desk staffing: 8 labs on one IT team's data.
IT & TechForecast like a data-driven agile team: velocity ranges, sprint capacity, release dates, burndown charts, cycle time, Little's law, WSJF, confidence buffers and cost per story point in 8 hands-on labs.
IT & TechLearn what SELECT, WHERE, ORDER BY, GROUP BY, HAVING, JOINs, DISTINCT, CASE WHEN and date functions do by building every query result yourself with spreadsheet formulas, on live auto-graded labs.
IT & TechLittle's Law, M/M/1 queueing delay, p95/p99 latency, transfer times, storage growth, servers for the peak, serial/parallel availability, the load-test knee and cost per 1,000 requests: 8 labs on one ticketing platform.
IT & TechMeasure software delivery from real-looking deploy and incident logs: deployment frequency, lead time, change failure and rework rate, time to restore, performance tiers, flow metrics with Little's law, SLO error budgets and a trend dashboard, every cell checked live.
IT & TechRun the numbers a test manager reports every day: execution status, defect density, defect removal efficiency, severity × priority matrix, defect ageing, test estimation, requirement coverage and a Go/No-go release checklist, every cell checked live.
IT & TechRun the energy numbers of a data centre hands-on: IT load and kWh, PUE and DCiE, stranded rack power, cooling tons, N+1 and 2N UPS capacity, savings and payback of PUE projects, location- and market-based carbon with CUE, and AI rack density against capacity, every cell checked live.
IT & TechLearn subnetting by calculating it: binary octets with DEC2BIN and BIN2DEC, IP addresses as 32-bit integers, CIDR masks and wildcards, network and broadcast addresses, usable hosts, equal subnets of a /24, VLSM plans and IPv6 /64 counts, every cell checked live.
IT & TechMeasure a SOC from synthetic logs: incident MTTD and MTTR with medians and percentiles, true-positive rate per detection rule, analyst workload and queues, CVSS bands and SLA compliance, patch coverage, phishing trends, risk-based prioritisation and a flagged KPI scorecard, every cell checked as you go.
IT & TechLCP, INP and CLS at the 75th percentile, good/needs-improvement/poor shares, page weight budgets, 3G/4G transfer times, CDN hit ratio, compression savings and the link to conversion: 8 labs on one fictional online shop.
IT & TechRun durations and p95, rows per second and GB per hour, freshness SLAs, failure and retry rates, backlog catch-up, storage growth and partition sizing, cost per TB and a data quality dashboard: 8 labs on one fictional company's ETL logs.
IT & TechHands-on labs for engineers and product people who run or consume APIs: requests per second vs limits, a token bucket step by step, fixed vs sliding windows, exponential backoff with jitter, 429 rates and retry success, quotas per plan tier, batching and caching savings, and cost per customer with a margin chart, every cell checked as you go.
IT & TechActive vs purchased seats, shelfware cost, tier right-sizing, annual vs monthly billing, true-ups at renewal, EDATE renewal calendars and notice deadlines, tool consolidation and spend per employee: optimise a company's SaaS licences in a live spreadsheet that checks every cell.
IT & TechRAID usable capacity and TB vs TiB, AFR and rebuild risk, backup windows, incremental vs differential volumes, GFS retention, dedupe and compression, cloud vs tape cost per TB-month and an RPO/RTO check with a chart: 8 labs on one post-production studio.
IT & TechCrash-free users and sessions, crashes per 1,000 sessions by version, ANR and freeze rates, p50/p90 cold start, crash-cluster Pareto, staged-rollout halt rules, regression z-tests and a stability dashboard: 8 labs on one fictional app's releases.
IT & TechMillicores and Mi/Gi, requests vs limits, p95 right-sizing, pods per node, node counts with DaemonSets and N+1, first-fit bin packing, cost per service and autoscaler replicas through the day: 8 graded labs on one fictional cluster.
IT & TechTrack laptop age and warranty with DATEDIF and EDATE, measure failure rates by age, build TCO per device, find the best refresh cycle by equivalent annual cost, compare lease and buy, budget refreshes by year, price disposal and weigh longer life against CO2, every cell checked. Fictional 500-person company, illustrative figures.
IT & TechDefensive password maths in a spreadsheet: character sets and search spaces, entropy bits, diceware-style passphrases, time to crack under illustrative attack speeds, length vs complexity, policy comparison with blocklists and MFA, reuse risk across sites and lockout math.
IT & TechHex to RGB, sRGB linearisation, relative luminance, contrast ratios, AA/AAA for normal and large text, darkening a failing brand colour, a full palette contrast matrix with highlighting and a contrast report with a chart: 8 graded labs on one fictional design studio.
IT & TechRequest vs byte hit ratio, origin load and servers, tiered egress bills, cost with vs without a CDN, TTL and cache-key choices on Zipf popularity, latency gain, image savings and a commit-contract decision: 8 labs on one fictional media site.
IT & TechBits vs bytes and GiB, transfer times and the courier test, speed of light in fibre, bandwidth-delay product and TCP windows, the Mathis loss formula, header overhead and goodput, queueing delay and 95th-percentile WAN sizing: 8 labs on one fictional architecture firm.
IT & TechSize a production database the way DBAs do it: bytes per row and table size, B-tree index pages with fill factor, compound storage growth to the disk alert, IOPS and throughput from the query mix, cache hit ratio and buffer pool, replicas and backup retention, connection pools with Little's law and provisioned vs serverless cost, in 8 hands-on labs with illustrative numbers.
IT & TechConvert mA, µA, mAh and mWh, turn a state table into an average current, estimate battery life with temperature and self-discharge, price every radio message in mJ, chart sampling interval vs life, check peak current against internal resistance, budget a solar harvester and plan fleet battery swaps: 8 graded labs for a fictional sensor node.
IT & TechModel the economy of a fictional mobile RPG: currency faucets and sinks and inflation, exponential vs polynomial XP curves with a chart, drop rates and pity timers, completing a gacha collection, crafting cost trees, gem-pack pricing, player segments with ARPPU and ARPDAU and a reward table balanced to a target time-to-level: 8 graded labs with synthetic data and a responsible-design view.
IT & TechBuild a load inventory in W and VA, size a UPS with headroom on both ratings, estimate runtime, size battery strings for a target runtime, plan replacements for heat, size a generator for motor starts, model N+1 vs 2N availability and compare 10-year cost of ownership: 8 graded labs on a fictional server room.
IT & TechCalculate the parts for microcontroller projects: resistors, sensor readings, timing, PWM and a project power budget, with every cell checked as you go.
Work out what ads really earn in an app: impressions per user, fill rate, eCPM by format and country, rewarded video and the hybrid ads-plus-purchases model, with every cell checked as you go.
The annual loss expectancy formula, ALE = SLE × ARO with SLE = asset value × exposure factor, and how to value a safeguard. Worked example in Excel.
MTBF, MTTR and availability: MTBF ÷ (MTBF + MTTR), MTTA, the four meanings of MTTR and the downtime each number of nines allows. Excel example.
SQL JOINs explained with Excel: an INNER and a LEFT JOIN rebuilt with XLOOKUP, why unmatched rows vanish, NULL as "Unknown" and the duplicate-key trap.
Build a subnet calculator in Excel: IP to integer, CIDR to mask and wildcard, network and broadcast address, usable hosts, BITAND check. Excel example.
The WCAG contrast ratio formula, (L1 + 0.05) / (L2 + 0.05): hex to RGB, relative luminance, AA and AAA checks for six colour pairs. Excel example.
No. The courses use spreadsheet formulas only. They suit IT managers, engineers, analysts and students alike.
The labs use illustrative prices and figures, because real prices change often. The methods work with any provider's current rates.
Each course is a single purchase of $9.99. That covers every lesson and lab, the final exam and the certificate, with no subscription and nothing that renews.
Start with the recommended course and build your first result in the lab today.
