Our take
Panasonic NN-SN643S is a 1.2-cu.-ft., 1,200-W household inverter microwave with sensor cook/reheat and a documented optional 27-in. trim kit. Its reviewed specs do not establish turntable diameter or current offer status.
Consider NN-SN643S if its 1.2-cu.-ft. cavity suits your cookware and you value the documented inverter and sensor functions. The manual lists 1,200 W of cooking output and separately gives 1,480 W input at 12.4 A. Use the manual's countertop clearances, or verify the separate 27-in. NN-TK621SSAP kit and cabinet requirements if choosing built-in installation..
If exact tray diameter or another cabinet width is decisive, compare a model whose manual documents those measurements and a matching trim-kit number. Verify the complete NN-SN643S suffix and the separate kit before ordering.
Pros & cons
What could work for you, and what to consider before buying.
What works in its favor
- The household manual documents inverter cooking, sensor cook/reheat and Inverter Turbo Defrost.
- A 1.2-cu.-ft. cavity and 1,200-W cooking output are documented for this exact model.
- The manual names an optional stainless 27-in. NN-TK621SSAP trim kit while also giving countertop instructions.
What to weigh up
- The optional trim kit is a separate width-specific installation part.
- The reviewed specification comparison does not state a numeric turntable diameter.
- The historic Amazon ASIN did not verify a current exact offer or seller condition.
The key details
| Model covered | NN-SN643S |
|---|---|
| Capacity | 1.2-cu.-ft. cavity. |
| Microwave output | 1,200-W microwave cooking output. |
| Cooking approach | Inverter cooking, sensor cook/reheat, Inverter Turbo Defrost, and ten power levels. |
| Installation options | 120 V/60 Hz; countertop placement documented; 1,480-W/12.4-A input; optional separate 27-in. NN-TK621SSAP trim kit. |
| Finish and turntable | Stainless steel; numeric turntable diameter is not documented. |
Performance figures are manufacturer claims. Source checked October 5, 2026. Regional models and included accessories can differ.
What the features mean for you
Read the exact NN-SN643S documentation
Panasonic's manual covers NN-SN643S within its household microwave family and includes model-specific electrical and trim information. Keep the S suffix intact when comparing it with nearby NN-SN models; shared series wording alone is not enough to transfer dimensions or accessories. That boundary matters when checking a seller label, ordering a replacement part, or applying a cabinet-kit instruction: confirm the complete code before treating a family-level reference as an exact match.
Use the 1.2-cu.-ft. figure as cavity capacity
Panasonic's dimensional comparison lists this model at 1.2 cu. ft. That number describes cavity volume, not the diameter of a dish that will rotate. The reviewed spec table does not supply a numeric turntable diameter, so check the actual tray and opening if large plates are central to your decision. A tall bowl or handled dish can also meet the interior walls even when its nominal width is under the tray diameter. Measure the container you use most, and leave room for it to turn freely rather than treating capacity as a plate-size promise.
Separate output from electrical draw
The operating instructions list 1,200 W of cooking output and separately list 1,480 W of power consumption at 12.4 A. The output figure is the microwave cooking rating; use the separate electrical details and installation instructions when planning the outlet and circuit. These numbers answer different questions: output belongs in a cooking-power comparison, while input and amperage are the figures to check against the appliance label and the available household branch circuit. Do not convert one rating into the other or assume a shared outlet is suitable without checking the manual.
Compare inverter and sensor controls
The manual documents inverter technology, sensor cook/reheat and Inverter Turbo Defrost. These are specific control and power-delivery features; they are useful distinctions from timer-and-power-level-only models without promising a particular result for every recipe or portion. For routine reheating, the named sensor programs give the user an automatic control choice, while the ten power levels still allow manual selection for other tasks. A buyer who prefers to enter a time and level can use those controls instead of relying on a preset. The manual establishes which options exist, not a measured advantage over another microwave.
Choose countertop or matched trim installation
Panasonic provides stable countertop placement instructions and also names optional stainless trim kit NN-TK621SSAP, 27 in. wide. The frame is a separate installation route, not evidence that the kit comes with the microwave. Confirm the kit, opening and clearances before cabinet installation. Buyers who will leave it on the counter should follow the same model manual's ventilation directions; those who plan a cabinet opening need to match both the kit width and the exact appliance suffix before cutting or ordering parts.
Treat product age and offer identity separately
Panasonic's support page labels the guide as a discontinued 2013 product document. That is product-history information, not evidence about current availability. Historical ASIN B00J5GH4HC returned a cache miss; use the tagged exact-model search and verify the full NN-SN643S label and seller condition. A search destination can show different suffixes or bundles, so confirm the product nameplate and any included trim accessory with the seller. The review does not infer a present price or stock status from the old document or ASIN.
What else to compare
If exact tray diameter or a different cabinet width is decisive, compare another model whose manual gives those measurements and a matching trim-kit number. For this model, verify the complete NN-SN643S suffix and the separate kit before ordering.
Before you buy
What are capacity and cooking output?
Panasonic's dimension comparison lists 1.2 cu. ft.; the manual lists 1,200 W output.
What does the manual list for electrical input?
It lists 1,480 W and 12.4 A at 120 V/60 Hz, separately from cooking output.
Does NN-SN643S use inverter technology?
Yes. Panasonic's exact manual documents inverter cooking and Inverter Turbo Defrost.
Are sensor functions included?
The manual lists sensor cook and sensor reheat for the exact NN-SN643S model.
Which trim kit is named?
The manual names optional stainless NN-TK621SSAP, a 27-in. kit that is separate.
Is the historical ASIN a current offer?
No current offer was verified; the old page returned a cache miss. Search the exact model with the tagged link.
Where can I check the current price?
Use the Amazon link for current offers. Check the exact model, seller, product condition, delivery, and return terms. This page does not display a live price or confirm stock.
Sources & review basis
We use the following manufacturer documentation for the product features above. Our suitability notes and buying advice are editorial judgments based on those features, not measured performance results.
- Panasonic NN-SN643S operating instructions ↗ — checked October 5, 2026.
- Panasonic household-use operating instructions name NN-SN643S, countertop placement, sensor functions, Inverter Turbo Defrost, 1,200-W output, 1,480-W/12.4-A electrical input and optional NN-TK621SSAP trim. ↗ — checked October 5, 2026.
- Panasonic dimensional comparison lists NN-SN643S at 1.2 cu. ft. ↗ — checked October 5, 2026.
- Panasonic support page identifies the NN-SN643 guide as a 2013 discontinued-product document; it is not current-offer evidence. ↗ — checked October 5, 2026.
- Historical exact-ASIN page returned a cache miss; it does not establish a current offer. ↗Paid link · We may earn a commission. — checked October 5, 2026.
The decision
Panasonic NN-SN643S is a 1.2-cu.-ft., 1,200-W household inverter microwave with sensor cook/reheat and a documented optional 27-in. trim kit. Its reviewed specs do not establish turntable diameter or current offer status.
Is it the right fit?
Check the exact model and today’s offers on Amazon.