Engineering Tools Platform

Precision
tools for
builders.

1,300+ engineering tools across electronics, PCB, IoT, 3D printing, and more — each with a production-ready API. Free on the web, paid only when you go programmatic.

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API Testing ToolProgrammingBIN ↔ Intel HEX / SREC ConverterIoT / ArduinoCron Expression BuilderProgrammingDay CalculatorGeneral UtilityDrone Flight Time CalculatorDrones / UAVDrone Thrust-to-Weight & Hover ThrottleDrones / UAVESP32 Deep-Sleep Battery LifeIoT / ArduinoEV vs Petrol Cost CalculatorGeneral UtilityResin Exposure Time CalculatorResin PrintingFEP / Vat Life TrackerResin PrintingFlexi Pay Tax SimulatorIndia SpecificFPV Link Budget & Range CalculatorDrones / UAVGit Diff ↔ Patch File ConverterProgrammingGST Reverse Charge (RCM) CalculatorIndia SpecificLiPo C-Rating & Voltage Sag CheckerDrones / UAVLLM API Cost CalculatorProgrammingMOSFET Junction TemperatureElectronicsPCB Trace Width CalculatorPCB DesignDrone Photogrammetry GSD & Mission PlannerDrones / UAVQR Code GeneratorGeneral UtilityRent vs Buy CalculatorGeneral UtilityResin Cost CalculatorResin PrintingResin Volume CalculatorResin PrintingUV Post-Cure CalculatorResin PrintingAPI Testing ToolProgrammingBIN ↔ Intel HEX / SREC ConverterIoT / ArduinoCron Expression BuilderProgrammingDay CalculatorGeneral UtilityDrone Flight Time CalculatorDrones / UAVDrone Thrust-to-Weight & Hover ThrottleDrones / UAVESP32 Deep-Sleep Battery LifeIoT / ArduinoEV vs Petrol Cost CalculatorGeneral UtilityResin Exposure Time CalculatorResin PrintingFEP / Vat Life TrackerResin PrintingFlexi Pay Tax SimulatorIndia SpecificFPV Link Budget & Range CalculatorDrones / UAVGit Diff ↔ Patch File ConverterProgrammingGST Reverse Charge (RCM) CalculatorIndia SpecificLiPo C-Rating & Voltage Sag CheckerDrones / UAVLLM API Cost CalculatorProgrammingMOSFET Junction TemperatureElectronicsPCB Trace Width CalculatorPCB DesignDrone Photogrammetry GSD & Mission PlannerDrones / UAVQR Code GeneratorGeneral UtilityRent vs Buy CalculatorGeneral UtilityResin Cost CalculatorResin PrintingResin Volume CalculatorResin PrintingUV Post-Cure CalculatorResin Printing
LLM API Cost CalculatorProgrammingMOSFET Junction TemperatureElectronicsUV Post-Cure CalculatorResin PrintingResin Volume CalculatorResin PrintingQR Code GeneratorGeneral UtilityGST Reverse Charge (RCM) CalculatorIndia SpecificPCB Trace Width CalculatorPCB DesignRent vs Buy CalculatorGeneral UtilityResin Cost CalculatorResin PrintingDrone Flight Time CalculatorDrones / UAVAPI Testing ToolProgrammingEV vs Petrol Cost CalculatorGeneral UtilityFlexi Pay Tax SimulatorIndia SpecificDay CalculatorGeneral UtilityESP32 Deep-Sleep Battery LifeIoT / ArduinoDrone Photogrammetry GSD & Mission PlannerDrones / UAVLiPo C-Rating & Voltage Sag CheckerDrones / UAVBIN ↔ Intel HEX / SREC ConverterIoT / ArduinoFEP / Vat Life TrackerResin PrintingResin Exposure Time CalculatorResin PrintingDrone Thrust-to-Weight & Hover ThrottleDrones / UAVCron Expression BuilderProgrammingGit Diff ↔ Patch File ConverterProgrammingFPV Link Budget & Range CalculatorDrones / UAVLLM API Cost CalculatorProgrammingMOSFET Junction TemperatureElectronicsUV Post-Cure CalculatorResin PrintingResin Volume CalculatorResin PrintingQR Code GeneratorGeneral UtilityGST Reverse Charge (RCM) CalculatorIndia SpecificPCB Trace Width CalculatorPCB DesignRent vs Buy CalculatorGeneral UtilityResin Cost CalculatorResin PrintingDrone Flight Time CalculatorDrones / UAVAPI Testing ToolProgrammingEV vs Petrol Cost CalculatorGeneral UtilityFlexi Pay Tax SimulatorIndia SpecificDay CalculatorGeneral UtilityESP32 Deep-Sleep Battery LifeIoT / ArduinoDrone Photogrammetry GSD & Mission PlannerDrones / UAVLiPo C-Rating & Voltage Sag CheckerDrones / UAVBIN ↔ Intel HEX / SREC ConverterIoT / ArduinoFEP / Vat Life TrackerResin PrintingResin Exposure Time CalculatorResin PrintingDrone Thrust-to-Weight & Hover ThrottleDrones / UAVCron Expression BuilderProgrammingGit Diff ↔ Patch File ConverterProgrammingFPV Link Budget & Range CalculatorDrones / UAV
Domains

Every niche,
fully armed.

We build where others don't look — underserved engineering domains with zero good tooling online. Until now.

Electronics
200 tools
🔧
PCB Design
100 tools
🖨
3D Printing
150 tools
🔌
IoT / Arduino
100 tools
⚛️
Physics / Eng
150 tools
💻
Programming
200 tools
🇮🇳
India Specific
150 tools
🛠
General Utility
150 tools
💎
Resin Printing
40 tools
🛸
Drones / UAV
60 tools
⚔️
Browse all 10 domains
1,300+ tools and counting
Browse all
Featured tools

Built to be used,
not just listed.

Every tool runs instantly in your browser, free, and ships with a clean JSON API for production. Here's a slice across the catalog.

MOSFET Junction Temperature

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.

Electronics
PCB Trace Width Calculator

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.

PCB DesignIPC-2221
BIN ↔ Intel HEX / SREC Converter

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.

IoT / Arduino
API Testing Tool

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.

Programming
Flexi Pay Tax Simulator

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.

India SpecificFinance Act 2025 · IT Act 1961
Day Calculator

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.

General Utility
Resin Exposure Time Calculator

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).

Resin PrintingJacobs working-curve
Drone Flight Time Calculator

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.

Drones / UAV
Cron Expression Builder

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.

Programming
Browse all tools →
api.toolsamurai.com / v1
// PCB trace width calculator
POST /electronics/pcb-trace-width
Authorization: Bearer sk_live_•••••••••
{
"current_A": 3.5,
"temp_rise_C": 10,
"layer": "outer"
}
── 200 OK ──────────────
{
"ok": true,
"result": {
"trace_width_mm": 0.856,
"standard": "IPC-2221"
}
}
API

One key.
Every tool.

REST endpoints, clean JSON. Drop engineering intelligence into your app in minutes. No SDK required — just HTTP.

Pricing

Fair. Simple.

Designed for indie builders and teams. Start free, upgrade when you ship something real.

Free
₹0/mo
Everything to explore and prototype with no pressure.
  • 500 API calls / month
  • All tools, web & API
  • JSON responses
  • Community support
Get free key
Coming soon
Team
₹4,999/mo
White-label and scale across your entire product suite.
  • Unlimited API calls
  • White-label embedding
  • Custom tool requests
  • SLA guarantee
  • Dedicated support
FAQ

Questions,
answered.

Is ToolSamurai free?

Every tool runs free in your browser — no signup, no usage limits, and no ads on the calculators. The paid tier exists only for programmatic API access at scale.

Do the tools have an API?

Yes. Every tool has a matching JSON API at /api/v1/{domain}/{slug}. The free key includes 500 calls a month; paid tiers scale to 50,000+ and unlimited.

How accurate are the calculators?

Each tool documents the formula and the standard it follows, and ships with a test suite — nominal, edge, and invalid cases — that runs in CI before the tool goes live.

What makes ToolSamurai different?

We build the underserved corners of engineering — Indian standards like IS 456 and IS 875, modern PCB rules like IPC-2152, and full resin-printing workflows — that are usually paywalled or scattered across broken pages.

Can I use the results commercially?

Yes. The tools are free to use for personal and commercial work. For production integrations, the JSON API and (soon) white-label embedding cover that use case.