Reference

Changelog

What's new. Tools land here automatically — each tool's `added` date is its release stamp.

2026-05-26
  • Day Calculator — v1.0.0 · Calculate the exact number of days, weeks, months, or years between two dates, or add/subtract time from a date, with options to exclude weekends and holidays.
  • Git Diff ↔ Patch File Converter — v1.0.0 · Convert raw git diff output to downloadable .patch files or compare code snippets to generate patches 100% client-side. Find common git diff commands.
  • Rent vs Buy Calculator — v1.0.0 · Compare the long-term financial outcome of buying vs renting and investing the difference. Highly flexible, globally customizable with market presets.
2026-05-25
  • Drone Flight Time Calculator — v1.0.0 · Realistic flight-time estimate for any multirotor — uses hover efficiency (g/W), pack voltage, ESC efficiency, usable-capacity derating and a flight-style multiplier instead of the naive mAh ÷ current formula.
  • Drone Thrust-to-Weight & Hover Throttle — v1.0.0 · Compute thrust-to-weight ratio and hover throttle for any multirotor using the correct square-law throttle ↔ thrust relationship — not the linear approximation most calculators get wrong. Recommends a motor thrust to hit a target TWR.
  • FPV Link Budget & Range Calculator — Friis equation (ITU-R P.525) · v1.0.0 · Compute theoretical and practical line-of-sight range for any FPV video or control link using the Friis equation. Accounts for TX power, antenna gains, receiver sensitivity, system losses and fade margin, plus 60% Fresnel zone clearance for long-range planning.
  • LiPo C-Rating & Voltage Sag Checker — v1.0.0 · Verifies whether a LiPo pack can actually sustain your drone's continuous and burst current draw. Computes voltage sag from per-cell internal resistance and warns when manufacturer C-ratings are overstated.
  • Drone Photogrammetry GSD & Mission Planner — v1.0.0 · Compute ground sample distance, ground footprint, flight-line spacing, trigger interval and motion-blur speed limit for drone mapping missions. Add an area and battery flight time to get total image count, flight lines, mission duration, battery swaps and SD card size.
2026-05-20
  • EV vs Petrol Cost Calculator — v1.1.0 · Compare the real ownership cost of an EV and a petrol vehicle using the numbers buyers already know: price, claimed range, mileage, local fuel rates, daily driving, currency and ownership period.
2026-05-19
  • BIN ↔ Intel HEX / SREC Converter — v1.0.0 · Convert firmware images between raw binary, Intel HEX, and Motorola S-record. Validates checksums, preserves sparse address maps, handles linear and segmented Intel HEX addressing, and emits a raw hex preview for inspection.
  • Resin Exposure Time Calculator — Jacobs working-curve · v1.0.0 · Layer and bottom exposure plus Jacob's-curve cure depth from resin critical energy, penetration depth, printer LED power and layer height. Flags under-cure (delamination) and over-cure (brittle, blooming).
  • FEP / Vat Life Tracker — v1.0.0 · Estimate remaining FEP film life from accumulated print hours, average layer exposure, bottom-layer abuse and vat film type. Bottom exposures and high LED power age the film faster — both are factored in.
  • Resin Cost Calculator — v1.0.0 · Per-print cost from resin used, bottle price, electricity and consumables — with a wastage uplift so failed prints don't surprise you. Returns total cost plus effective ₹ per ml and ₹ per gram.
  • Resin Volume Calculator — v1.0.0 · Estimate how much resin a print will consume from the model volume, support overhead, raft and failure-buffer percentages — plus how much to pour into the vat including the FEP coverage minimum.
  • UV Post-Cure Calculator — v1.0.0 · Estimate post-cure time in a wash-and-cure station from part thickness, resin type, UV intensity, wavelength match and rotation. Flags under-powered stations and over-cure brittleness.
2026-05-17
  • API Testing Tool — v1.0.0 · Free in-browser API testing tool (Postman alternative). Fire HTTP requests (GET, POST, PUT, DELETE, etc.) against any URL straight from your browser with custom headers and body.
  • Cron Expression Builder — v1.0.0 · Build a cron expression part-by-part, get a plain-English description, and preview the next five scheduled runs in your timezone. Handles ranges, lists, step values, and named days.
  • Flexi Pay Tax Simulator — Finance Act 2025 · IT Act 1961 · v1.0.0 · Compare Old vs New tax regime for FY 2025-26 (Finance Act 2025). Handles HRA, flexi bucket (food, NPS, LTA, mobile, uniform, prof-dev), 80C/80D/80CCD1B/24B, 87A rebate and surcharge tiers. Returns total tax, monthly TDS, effective rate, and a regime pick.
  • LLM API Cost Calculator — v1.0.0 · Estimate monthly API cost for any LLM workload across Anthropic and OpenAI models. Includes prompt-cache and batch-API math so you see what you actually pay — not just the headline rate.
  • QR Code Generator — v1.0.0 · Generate a QR code from text, URL, or any payload. Pick foreground colour, background colour (or transparent), error correction level, margin and size. Returns SVG, base64 data URL, and ASCII preview.
2026-05-16
  • ESP32 Deep-Sleep Battery Life — v1.0.0 · Project lifetime for an ESP32 (or any duty-cycled MCU) running on battery. Computes average current and lifetime from sleep current, wake current, wake duration, cycle period, and battery derating.
  • GST Reverse Charge (RCM) Calculator — CGST Act §9(3) / IGST Act §5(3) · v1.0.0 · Compute the GST liability under the Reverse Charge Mechanism — the supplier doesn't collect tax, the recipient self-assesses it. Splits CGST/SGST or IGST, and flags Input Tax Credit eligibility.
  • MOSFET Junction Temperature — v1.0.0 · Compute MOSFET junction temperature from drain current, RDS(on), thermal resistance, ambient temperature and duty cycle. Flags marginal and danger conditions against the configured Tj-max.
  • PCB Trace Width Calculator — IPC-2221 · v1.0.0 · IPC-2221 compliant trace width for a given current, temperature rise, copper weight, and layer position. Returns width in millimetres and mils plus cross-sectional area.