Browse and search our growing collection of engineering tools.
OpenAI Cost
Calculate the exact cost of OpenAI API calls by model. Enter input and output tokens to estimate GPT-4o, o1, and GPT-3.5 pricing instantly — no sign-up required.
JSON Size
Instantly calculate the byte size and KB of any JSON string. Validates syntax in real time. Essential for API payload optimization and size limit checks.
Rate Limit
Calculate total API requests allowed in any time window from your rate limit. Enter RPS and duration to plan capacity and avoid 429 throttling errors.
Base64 Size
Calculate Base64 encoded size from original bytes. See the exact output size and ~33% overhead — instant results for API payloads, images, and JWT tokens.
Cron Next Run
Calculate the next run times for any cron expression instantly. Enter your cron schedule and start time to see exactly when your job will execute next
Latency Budget
Calculate your latency budget across service components. Allocate ms targets for each layer and instantly see remaining headroom or where you're over budget
Cache Hit Rate
Calculate cache hit rate instantly — enter total requests and cache hits to get hit %, miss %, and origin load. Works for CDN, Redis, Memcached, and browser caches.
QPS
Calculate QPS (queries per second) from request volume and time window. Estimate average and peak throughput for API capacity planning — no sign-up required
Throughput
Calculate throughput in requests per second and MB/s from total requests and time window. Instant API and system capacity planning — no sign-up required.
Concurrency
Calculate required API concurrency using Little's Law. Enter RPS and average response time to size connection pools, thread pools, and worker counts instantly.
Bandwidth Cost
Calculate bandwidth cost by entering monthly transfer volume and price per GB. Instant egress cost estimates for AWS, GCP, Azure, Cloudflare, and major CDN providers.
Storage Cost
Use this storage cost calculator to estimate monthly and total cloud storage spend. Enter data size, price per GB, and duration for an instant result.
Transfer Cost
Calculate data transfer cost by provider with this free data transfer cost calculator. Enter volume, price per GB, and free tier to get instant egress estimates.
Payload Size
Estimate API payload size in bytes, KB, or MB. Enter record count and average record size to calculate request payload, gzip estimate, and daily data volume.
HTTP Request Size
Calculate HTTP request size in bytes instantly. Enter method, URL length, headers, and body to estimate total payload size for API calls, gateways, and load balancers.
Regex Performance
Regex performance calculator — analyze any pattern for ReDoS risk, O(n) to O(n3) time complexity, and estimated execution time per run in milliseconds.
SQL Query Cost
Estimate SQL query costs on BigQuery, Athena, or Redshift Spectrum. Enter data scanned and query volume to instantly project your monthly database spend.
Pagination Perf
Calculate pagination performance for offset vs cursor-based queries. Enter total records, page size, and page number to see query time slowdown instantly.
Index Size
Index size calculator: instantly estimate how large a B-tree database index will grow given row count, key size, page size, and fill factor — no DBA needed.
Thread Pool Size
Calculate the optimal thread pool size for your application using CPU cores, utilization target, and I/O wait time. Based on the Brian Goetz formula.
Queue Throughput
Calculate worker queue throughput instantly — enter worker count, task duration, and queue size to see tasks/sec rate and queue drain time for any worker pool
Retry Backoff
Calculate exponential retry backoff delays for your API calls. Enter initial delay, multiplier, and max retries to see per-attempt wait times and total retry budget instantly.
Timeout
Calculate the optimal timeout value for API calls and network requests. Enter P99 latency and a safety multiplier to get a recommended timeout instantly.
Response Time
Estimate API response time by combining network latency, server processing, payload transfer, and middleware overhead — results in milliseconds, no sign-up needed
Compression Ratio
Calculate compression ratio instantly — enter original and compressed file sizes to get the ratio, space savings percentage, and bytes saved. Works for any format
Upload Time
Use this file upload time calculator to estimate how long any upload takes — enter file size and connection speed for an instant result, no sign-up needed.
Download Speed
Download speed calculator — enter file size (MB) and connection speed (Mbps) to estimate exact download time. Works for any file type or network speed
TLS Handshake
Calculate TLS handshake time for TLS 1.2 and TLS 1.3 by entering your network RTT and certificate validation overhead. Optimize HTTPS latency before shipping.
CDN Cost
Calculate your monthly CDN cost by data transfer and requests. Estimate CloudFront, Cloudflare, and Fastly pricing instantly — no sign-up required.
Lambda Cost
Calculate AWS Lambda monthly costs by memory, duration, and invocations. Estimate execution and request charges instantly — no sign-up required.
K8s Resources
Calculate Kubernetes resource requests and limits across pods. Enter replicas, CPU millicores, and memory MiB to plan cluster capacity and avoid OOMKill or throttling.
Pod Capacity
Calculate how many pods fit on a Kubernetes node using CPU and memory requests. Instantly find your scheduling bottleneck — no cluster access required.
CPU Usage
Estimate CPU usage percentage from requests per second, CPU time per request, and core count. Free cpu usage estimator for backend capacity planning.
Memory Usage
Calculate memory usage for any dataset or data structure. Enter item count, bytes per item, overhead %, and replicas to get total RAM requirements instantly.
Disk IOPS
Calculate disk IOPS from seek time, RPM, block size, and transfer rate. Instantly estimate HDD and SSD storage performance — no sign-up required.
RAID Capacity
Calculate RAID storage capacity for RAID 0, 1, 5, 6, and 10 arrays. Enter disk count and size to see usable capacity and storage efficiency instantly
Cache TTL
Use the cache TTL impact calculator to estimate hit rate, origin load reduction, and monthly bandwidth savings for your CDN or application cache configuration
Event Rate
Calculate the event processing rate for your pipeline. Enter worker count, per-event latency, and total events to get throughput and queue drain time instantly
Queue Delay
Calculate message queue delay with this free calculator. Enter queue depth, consumer rate, and latency to estimate end-to-end delay instantly — no sign-up
Batch Processing Time
Batch processing time calculator: given item count, processing rate, and workers, calculate total job duration instantly in seconds, minutes, or hours
API Pagination
Calculate total pages, fetch time, and request count for paginated API calls. Enter total records, page size, and rate limit to plan your data sync instantly.
Token Bucket
Calculate token bucket rate limits instantly. Enter bucket capacity, refill rate, and request cost to find max RPS, burst capacity, and wait time for blocked requests.
Leaky Bucket
Calculate leaky bucket rate limiting: effective throughput, drop rate, and bucket fill time from incoming request rate, leak rate, and bucket capacity.
Hash Collision
Calculate hash collision probability for any hash function size. Enter item count and bit width to estimate birthday problem collision risk instantly.
Encryption Overhead
Encryption overhead calculator: measure AES-256-GCM, AES-128-GCM, AES-256-CBC, and ChaCha20 ciphertext size, overhead bytes, and encryption time in ms
Session Size
Calculate session size in tokens for LLM API calls. Enter system prompt, turn count, and message lengths to find context window usage and overflow limits.
Log Storage Cost
Calculate log storage cost by daily volume, retention, and compression ratio. Estimate monthly spend for S3, GCS, or any object storage — no sign-up needed.