Enter Welding and Job Details
Use the responsive form below. It displays three columns on large screens, two on smaller screens, and one on mobile.
Formula Used
The calculator applies common welding heat input relationships with an efficiency correction. These formulas help compare procedures, travel speeds, and expected thermal loading.
| Metric | Formula | Meaning |
|---|---|---|
| Arc Power | P = (V × I) / 1000 | Converts volts and amps into kilowatts. |
| Heat Input | HI = (V × I × 60 × η) / (1000 × S) | Returns effective heat input in kJ/mm when speed is in mm/min. |
| Arc Time | t = Total Weld Length / Travel Speed | Estimates active welding time for all passes. |
| Total Arc Energy | E = P × t(seconds) | Finds gross arc energy before efficiency correction. |
| Effective Workpiece Energy | Eeff = E × η | Estimates net heat transferred into the workpiece. |
Symbols: V = voltage, I = current, η = thermal efficiency, S = travel speed.
How to Use This Calculator
- Select the welding process or choose Custom for manual efficiency control.
- Enter voltage, current, and travel speed using the correct unit set.
- Input weld length and the number of passes for the complete joint.
- Add material, thickness, operator, and job details for reporting clarity.
- Press the calculate button to show the result section below the header.
- Review heat input, total energy, arc time, and classification together.
- Use CSV or PDF export buttons for documentation and handoff.
Example Data Table
This sample illustrates a practical welding setup and the resulting heat input metrics.
| Process | Voltage | Current | Speed | Efficiency | Length | Passes | Heat Input | Total Energy |
|---|---|---|---|---|---|---|---|---|
| GMAW / MIG | 24 V | 220 A | 300 mm/min | 0.80 | 500 mm | 1 | 0.845 kJ/mm | 422.400 kJ |
| FCAW | 29 V | 260 A | 350 mm/min | 0.85 | 600 mm | 2 | 1.099 kJ/mm | 1318.114 kJ |
| GTAW / TIG | 14 V | 150 A | 180 mm/min | 0.60 | 250 mm | 1 | 0.420 kJ/mm | 105.000 kJ |
Frequently Asked Questions
1. What does heat input mean in welding?
Heat input describes the thermal energy delivered per unit weld length. It helps predict penetration, cooling behavior, distortion risk, and possible metallurgical changes in the heat affected zone.
2. Why is thermal efficiency included?
Not all electrical arc energy enters the workpiece. Thermal efficiency adjusts for process losses, making comparisons between welding methods more realistic and better aligned with fabrication practice.
3. Which travel speed unit should I choose?
Choose the unit that matches your procedure sheet or machine display. The calculator converts mm/min, cm/min, and in/min internally before computing consistent heat input values.
4. Does higher heat input always improve penetration?
Not always. Higher heat input can increase fusion, but it may also increase distortion, enlarge the heat affected zone, and reduce cooling rates too much for some materials.
5. Can I use this for multi-pass welds?
Yes. Enter the single pass length and number of passes. The calculator expands total weld length, arc time, and energy so you can estimate the full joint heat load.
6. What is a good heat input range?
Acceptable values depend on material, thickness, welding code, consumables, and toughness requirements. Always compare this result with your qualified procedure, code limits, and metallurgical targets.
7. Why does travel speed strongly affect the result?
Heat input is inversely related to speed. Slower travel places more energy into each millimeter of weld, while faster travel spreads the same power over more length.
8. What do the CSV and PDF buttons export?
The CSV button exports the current result summary as spreadsheet-ready rows. The PDF button saves the visible result report, which is useful for job files and procedure reviews.