Psu Watt Calculator
Picking a power supply starts with one number: how many watts your parts actually draw. This PSU watt calculator adds up worst-case draw per component, from CPU and GPU board power down to fans and drives, then recommends a PSU wattage with 25% headroom, shows the load percentage on that recommended unit, and optionally prices the yearly running cost at your electricity rate. CPU and GPU presets carry real published power figures, so you can skip the spec-sheet hunt. Presets now cover the RTX 50-series, RX 9000 series, Ryzen 9000 series and Core Ultra 200 series alongside the older generations.
Preset figures are published max board-power numbers, not measured gaming draw, so the estimate is deliberately conservative. The fixed 80W motherboard allowance is a planning figure, not your board’s exact draw. Yearly cost assumes full load; typical gaming loads land at 50–80% of that.
Quick Answer
A build with an Intel i7-14700K (219W), an RTX 4070 Super (220W), 2 RAM modules, 2 drives, 4 fans, and 50W of peripherals draws an estimated 615W. With 25% headroom (615 × 1.25 = 768.75), the tool recommends an 800W PSU that runs at about 77% load at full tilt. At $0.17/kWh and 6 hours a day, that load costs roughly $228.96 per year in electricity.
Key takeaways
- The estimate is deliberately conservative: presets use published power figures, not the lower power a system draws while gaming: GPU board power (TGP/TBP) and, for CPUs, AMD TDP or Intel maximum turbo power, matching the convention of the existing presets.
- The recommendation is load × 1.25, rounded up to the next 50W. That headroom absorbs GPU transient spikes, capacitor aging, and a future upgrade.
- Wattage is the headline, but the 80 Plus rating and the +12V rail decide running cost and reliability; a cheap no-name "800W" unit may not deliver 800W on the 12V rail.
- PSUs are most efficient near 50% load, so one step up from the recommendation is sensible future-proofing, while three times your load wastes money twice.
How to use the PSU watt calculator
Enter your parts, press Calculate, and read four numbers: estimated load, recommended PSU, load percentage, and optionally the yearly running cost. The results stay hidden until you calculate.
- Set CPU and GPU power: the worked example is pre-filled (i7-14700K at 219W, RTX 4070 Super at 220W). Pick your parts from the preset lists (now including RTX 50-series, RX 9000, Ryzen 9000 and Core Ultra 200 parts) to fill in their published power figures, or choose Custom and type your own figure.
- Count the rest: number of GPUs, RAM modules, storage drives, case fans, and a watt estimate for other peripherals such as a pump, RGB strips, or a capture card.
- Set the overclock headroom: leave None for a stock build. Light, Moderate, and Heavy add 10%, 20%, or 30% to the CPU + GPU figure only, because those two parts absorb nearly all of an overclock's extra draw.
- Optionally price the running cost: enter your electricity price per kWh and daily hours to add a yearly cost line. Leave both blank and the cost line simply does not appear.
The tool rejects negative entries with "Please enter valid positive values." and requires at least one of CPU or GPU wattage: with both at zero it asks you to "Enter at least your CPU or GPU wattage." Blank optional fields are treated as zero, not as errors.
Worked example: 615W load, 800W recommendation
An Intel i7-14700K (219W) plus an RTX 4070 Super (220W), with 2 RAM modules, 2 drives, 4 fans, and 50W of peripherals at stock settings, adds up as:
| Component | How it is counted | Watts |
|---|---|---|
| CPU | i7-14700K board power | 219 |
| GPU | RTX 4070 Super board power × 1 | 220 |
| Motherboard | Fixed planning allowance | 80 |
| RAM | 2 modules × 3W | 6 |
| Storage | 2 drives × 10W | 20 |
| Fans | 4 fans × 5W | 20 |
| Peripherals | As entered | 50 |
| Estimated system load | 615 |
Recommended PSU = 615 × 1.25 = 768.75, rounded up to the next 50W = 800W, which the system loads to about 77% at full tilt. With $0.17/kWh and 6 hours a day, the yearly cost line reads $228.96 (615/1000 × 6 × 365 × 0.17). Enter these values and the tool reproduces every figure exactly.
How the estimate works
The tool adds up worst-case draw per part, multiplies CPU + GPU by the overclock factor, and then sizes the PSU at 1.25× the total, rounded up to the next 50W. The formula never changes; only your inputs do.
Recommended PSU = ceil(total × 1.25 / 50) × 50 | Load % = total / recommended × 100
Yearly cost = total / 1000 × hours × 365 × $/kWh (only when both price and hours are positive)
The 25% headroom is doing three jobs at once: it absorbs GPU transient spikes, which can briefly exceed rated board power for milliseconds; it covers capacitor aging, which slowly erodes a unit's effective capacity; and it leaves room for a future upgrade without a second PSU purchase. The rounding to 50W steps matches how PSUs are actually sold: nobody sells a 769W unit.
New-generation presets, and one caution: the RTX 50-series presets use NVIDIA’s published total graphics power (5090 575W, 5080 360W, 5070 Ti 300W, 5070 250W, 5060 Ti 180W, 5060 145W, 5050 130W); RX 9000 presets use AMD’s typical board power (9070 XT 304W, 9070 220W, 9060 XT 16GB 160W); Ryzen 9000 presets use AMD default TDP (9950X 170W, 9900X 120W, 9800X3D 120W, 9700X 65W, 9600X 65W); Core Ultra 200 presets use Intel maximum turbo power (285K 250W, 265K 250W, 245K 159W). These are reference figures: a factory-overclocked partner card can draw more than the reference board power, so if your card’s own spec sheet lists a higher figure, choose Custom and type that figure in. The 9060 XT 8GB variant is rated 150W, not 160W, so 8GB owners should also use Custom.
To put your electricity price in context, the cost per kWh calculator breaks down what a kilowatt-hour really costs you, and the cost of energy calculator compares running costs across appliances. If the wattage figure itself needs checking against volts and amps, the amp watt calculator converts between the three.
Choosing the right PSU, not just the right wattage
Wattage decides whether the system stays on; efficiency and build quality decide the running cost and whether the system survives. Three checks beyond the headline number:
- The 80 Plus rating: it certifies how much of the wall power becomes DC output instead of heat. At 115V and 50% load, the tiers run Standard 80%, Bronze 85%, Silver 88%, Gold 90%, Platinum 92%, and Titanium 94%, per the certification tables summarised in Seasonic's 80 Plus efficiency explainer. A Gold unit wastes less electricity as heat than a Bronze unit at the same wattage.
- Transient handling: modern GPUs spike well above their rated draw for milliseconds. Intel's ATX 3.0 specification formalised this with a power-excursion requirement (up to 200% of rated power for 100 microseconds on larger units), as covered in PCWorld's ATX 3.0 explainer and the ATX 3.0 vs 3.1 guide from Overclockers UK. If you are buying a current high-end GPU, an ATX 3.x unit is the safer choice; this is part of what the 25% headroom is buying you.
- Quality over the label: buy from established makers (Seasonic, Corsair, be quiet!, Super Flower and similar) and check professional reviews, because a cheap no-name "800W" unit may not deliver 800W on the 12V rail where it counts.
Do not oversize wildly, either. PSUs are most efficient near 50% load, which is a second reason for the headroom: a 615W peak on an 800W unit means typical gaming loads of 400–500W land around the efficiency sweet spot instead of pinned at the top of the range. But a 615W load on a 1600W PSU idles in the inefficient low-load region and wastes money twice, on the purchase price and on electricity.
What competing calculators miss
The well-known PSU calculators each optimise for a different user, and each has a blind spot:
- OuterVision: the most detailed component database and it does estimate yearly energy cost, but the sheer depth of sub-menus can overwhelm a first-time builder, and its detail can push the recommended wattage higher than a transparent parts-list estimate.
- Newegg's PSU calculator: fast and beginner-friendly, integrated with Newegg's product listings, but basic: a general estimate rather than a part-by-part build-up you can audit.
- Cooler Master: a clean breakdown with a recommended wattage range and a list of its own units, but it asks you to know every part's wattage yourself before it can help.
- be quiet!: quick and simple, good enough for a rough idea, but far less precise than the part-by-part tools.
- The gap this page fills: one-click CPU and GPU presets, now covering the current RTX 50, RX 9000, Ryzen 9000 and Core Ultra 200 generations as well as older parts, with real published power figures instead of a blank form, the complete arithmetic shown step by step so you can check it by hand, the load percentage on the recommended unit, and an optional yearly running-cost line, all without an account or a product catalogue steering the answer.
Frequently asked questions
Most single-GPU gaming builds land between 400W and 700W of estimated load, which maps to 550W to 1000W PSUs after the 25% headroom. Enter your exact parts above for a precise figure: the recommendation changes with every component.
Usually yes with an efficient CPU: a Ryzen 7 7800X3D (120W) plus an RTX 4070 Super (220W) totals about 516W of load, which maps to a 650W unit after headroom, running at 79% load. A hungrier 181W CPU pushes the same build to a 750W recommendation, so check the tool with your exact parts.
Expect shutdowns or reboots under load, especially during GPU transient spikes, which briefly exceed rated board power. In the worst case, an overloaded cheap PSU can fail and damage components. Size with headroom rather than to the exact load.
It certifies at least 90% efficiency at 50% load on 115V (87% at 20% and 100% loads). A Gold unit converts more of the wall power into DC output and wastes less as heat than a Bronze unit at the same wattage, which lowers the running cost.
The 80W is a fixed planning allowance covering the board itself plus chipset, VRMs, and the small devices that hang off it. It is deliberately conservative: real boards draw less at idle, but sizing against the worst case keeps the recommendation on the safe side.
One step up from the recommendation (for example 850W instead of 750W) is reasonable future-proofing, and PSUs are most efficient near 50% load. Three times your load is not: efficiency drops at very low loads, and you pay for capacity you never use.
Yes. Use the overclock headroom option: heavy overclocks add up to 30% to the CPU + GPU figure, which often pushes the recommendation up one PSU size. A 253W CPU plus a 450W GPU, for example, moves from a 1000W recommendation at stock to 1250W at heavy OC, even with no other parts drawing power.
Enter your electricity price per kWh and daily hours above. The estimate assumes full load, so real gaming loads typically cost 50–80% of the figure shown. At $0.17/kWh and 6 hours a day, the 615W worked example costs about $228.96 per year.
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References
- Seasonic. PSU Efficiency: 80 PLUS and Cybenetics Explained, with the full 115V/230V certification tables. Accessed October 24, 2026.
- PCWorld. ATX 3.0 Explained: Why Intel Just Gave Power Supplies a Major Overhaul, on power excursions and transient handling. Accessed October 24, 2026.
- Overclockers UK. ATX 3.0 vs ATX 3.1: What You Need to Know About PSUs, covering the 200% excursion requirement and the 12VHPWR connector. Accessed October 24, 2026.
- CCL Online. ATX 3.0 PSUs Explained: Will You Need One? Accessed October 24, 2026.
- Tom's Hardware forums. How 80+ Efficiency in PSUs Works, with the official 80 PLUS program description. Accessed October 24, 2026. NVIDIA. GeForce RTX 50 Series graphics card specifications (total graphics power for the RTX 5090, 5080, 5070 Ti, 5070, 5060 Ti, 5060 and 5050). Accessed October 24, 2026. AMD. Radeon RX 9000 Series specifications (typical board power for the RX 9070 XT, RX 9070 and RX 9060 XT). Accessed October 24, 2026. AMD. Ryzen 9000 Series processor specifications (default TDP for the Ryzen 9 9950X, 9900X, 7 9800X3D, 9700X and 5 9600X). Accessed October 24, 2026. Intel. Core Ultra 200S Series processor specifications (maximum turbo power for the Core Ultra 9 285K, Ultra 7 265K and Ultra 5 245K). Accessed October 24, 2026.