Calculator Inputs
Example Data Table
| Build profile | Heat load | Fan size | Target delta | Typical outcome |
|---|---|---|---|---|
| CPU-only quiet loop | 180 W | 120 mm | 8 °C | 240 to 360 radiator |
| Midrange CPU plus GPU | 420 W | 120 mm | 10 °C | 360 radiator with margin |
| High-end gaming loop | 650 W | 140 mm | 10 °C | 420 or 560 radiator |
| Heavy overclocked workstation | 900 W | 140 mm | 7 °C | 560 plus 280 radiator |
Formula Used
This tool estimates radiator capacity from a tuned per-section baseline. One 120 mm section starts at 125 W at a 10°C coolant-air delta.
Per-section capacity at 10°C = 125 × size factor × thickness factor × RPM factor × FPI factor × configuration factor × airflow factor
Per-section capacity at target delta = Per-section capacity at 10°C × (target delta ÷ 10)
Required sections = ceil((heat load × (1 + safety margin)) ÷ per-section capacity at target delta)
Estimated coolant delta with installed sections = (heat load ÷ installed capacity at 10°C) × 10
The model is an engineering estimate. Real performance changes with fan curves, shrouds, dust filters, case pressure, radiator brand, coolant flow, and thermal paste quality.
How to Use This Calculator
- Enter the sustained heat load from your CPU, GPU, and other loop components.
- Set your room temperature and target coolant-to-air delta.
- Choose radiator fan size, speed, thickness, and fin density.
- Select push, pull, or push-pull, then estimate case airflow quality.
- Enter how many radiator sections you already have installed.
- Add a safety margin for seasonal heat, dust, and future upgrades.
- Submit the form and review required sections, margin, and coolant estimates.
- Use the chart to compare expected dissipation at different deltas.
FAQs
1. What heat load should I enter?
Use sustained CPU and GPU power, not PSU capacity. Add pumps or motherboard heat only when they meaningfully warm the coolant.
2. Is one 120 section per 100 watts always correct?
No. It is a quick rule only. Fan speed, radiator thickness, ambient temperature, and target coolant delta can shift the needed area a lot.
3. Why does ambient temperature matter so much?
Radiators reject heat to room air. Warmer intake air reduces the temperature difference that drives heat transfer, so the same radiator removes less heat.
4. Does push-pull always improve cooling?
Usually it helps, especially on denser or thicker radiators. The gain is real, but it is not a clean doubling of performance.
5. Are thicker radiators always better?
Not always. Thick cores can add capacity, but they also need enough airflow and pressure. Weak fans may waste that extra depth.
6. What coolant delta is a good target?
Quiet builds often target 7 to 10°C. Performance-focused loops may accept 10 to 15°C. Lower deltas need more radiator area.
7. Why can real results differ from this estimate?
Real loops vary by radiator design, fan curve, filter restriction, case recirculation, flow rate, coolant mix, and sensor accuracy.
8. Should I oversize my radiator setup?
Oversizing usually improves noise and summer performance. It also gives room for dust buildup, warmer rooms, and future component upgrades.