Which Rational suits
my kitchen?
The choice comes down to four questions: what size, 1/1 or 2/1, Pro or Classic, and new or used. Answer them in that order and the rest falls into place. This guide walks through them, using Rational capacity guidelines as the starting point.
By Jos Menting, JMGT Commercial Kitchen Equipment · Authorised Rational dealer · Last updated 1 August 2026
In short
Choose on meals served on your busiest day: up to about 100 a 6-1/1 (or the XS if space is tight), 80 to 150 a 10-1/1, 150 to 300 a 20-1/1. Move to 2/1 as soon as you work with large GN containers as a matter of routine. Choose the Pro with changing staff and the Classic with a fixed, experienced brigade. Only then decide new or used.
Step 1: what size fits your output?
Rational uses a guideline based on the number of meals a day. Take that as a starting point and then correct for how you actually work: many courses at once, many containers at once or a short service peak all call for one size more than the average would suggest.
| Model | Guideline meals per day | Typical kitchen |
|---|---|---|
| iCombi Pro XS (6-2/3) | Small volume, supplementary or compact | Bar, food truck, room service, small venue with little space |
| 6-1/1 | approx. 30 - 100 | Restaurant, lunchroom, bistro, small hotel |
| 10-1/1 | approx. 80 - 150 | Busy restaurant, hotel, staff restaurant |
| 20-1/1 | approx. 150 - 300 | Large-scale kitchen, care institution, catering |
| 6-2/1, 10-2/1, 20-2/1 | As above, with double GN size per level | Production kitchen, care, catering with large containers |
Capacity guidelines for 6-1/1, 10-1/1 and 20-1/1 according to RATIONAL. Practice depends on menu, courses and peak pattern.
Step 2: 1/1 or 2/1?
The figure after the dash is the gastronorm size of the racks. A 1/1 unit takes GN 1/1 containers of 530 by 325 mm, a 2/1 unit takes containers of 650 by 530 mm. At the same number of levels, 2/1 delivers roughly double the volume, at the cost of a considerably wider machine.
Rule of thumb: if you work with 1/1 containers and plates, stay with 1/1. If you routinely work with large containers, baking trays or whole batches, as in a care institution, catering kitchen or central production kitchen, 2/1 is more efficient per batch. Do not pick 2/1 because it sounds bigger: you also buy a larger footprint and a higher connected load.
Step 3: iCombi Pro or iCombi Classic?
This is not a difference in quality but in who steers the cooking process. The iCombi Pro continuously measures what happens in the cabinet and adjusts humidity, time and temperature itself. The iCombi Classic carries out exactly what you set, without automatic correction.
The Pro pays off above all where staff change or are less experienced: the unit keeps the result consistent regardless of who presses the button. The full comparison is here: iCombi Pro vs iCombi Classic.
Not sure whether you need a combi oven at all or rather a cooking system? Then read: iVario vs combi oven.
Step 4: electric or gas, and will it physically fit?
Electric or gas. Electric is the standard: simpler to install, no gas connection or flue needed and in line with how most kitchens are decarbonising. Gas remains relevant with existing gas infrastructure or a tight electrical supply. The connected load often decides it, so involve your installer early.
Physical fit. Look beyond the width of the unit: clearance beside it for service, height including extraction, the route in (doors, thresholds, corners), floor loading for 20-level models, power, water connection and drain. If space is genuinely tight, the iCombi Pro XS at 65.5 cm wide is the smallest full-featured option: iCombi Pro XS review.
The full technical requirements are set out here: installing a combi oven: power, water and drainage. Pay particular attention to water hardness: without softening in a hard water area you shorten the life of the unit considerably.
What we see most often when surveying kitchens
During kitchen checks and site surveys we see two sizing mistakes again and again. The first is buying too small on the basis of an annual average. A restaurant doing fifty covers midweek but a hundred and forty at the weekend buys a 6-1/1 and then works in two batches every weekend. That costs plate timing and calm in the kitchen, exactly in the hours where the margin is made.
The second is the opposite: a 20-level unit in a kitchen that rarely fills half of it, because growth was once anticipated. You then pay daily in heat-up and floor space for capacity that never runs. In that case a 10-1/1 with a second unit added later is almost always the better route, not least because you are not brought to a standstill when one machine is being serviced.
So the three things we always ask first: how many covers on your busiest day, how many courses come out of the unit at once, and how experienced is the team using it. In practice those three answers determine the model. Build year, list price and features come afterwards.
Step 5: new or used?
Only once size and specification are settled does this question make sense. A refurbished Rational cooks identically to a new one and costs considerably less; a new unit gives you the latest software generation and full manufacturer warranty. More on this: new vs used Rational and is a used Rational reliable.
Next step
Send us your covers on the busiest day and a photo of the intended spot, and we will advise on the model and check that it fits.
Frequently asked questions
What size Rational do I need?
Rational gives the following guideline: a 6-1/1 for roughly 30 to 100 meals a day, a 10-1/1 for roughly 80 to 150 meals and a 20-1/1 for roughly 150 to 300 meals a day. Base it on your busiest day rather than the average, and allow for how many courses and preparations have to be in the unit at once.
What is the difference between 1/1 and 2/1 models?
The number refers to the gastronorm size of the racks. A 1/1 unit takes GN 1/1 containers (530 x 325 mm), a 2/1 unit takes the double size (650 x 530 mm). At the same number of levels, capacity roughly doubles, but the unit is also considerably wider. 2/1 is mainly used in production, care and catering kitchens.
iCombi Pro or iCombi Classic: how do I choose?
The Pro takes work off your hands: it measures, adjusts and corrects during cooking. The Classic does exactly what you set. If you work with changing or less experienced staff and want consistent results, the Pro pays for itself. With a fixed, experienced brigade the Classic is an excellent and cheaper choice.
Electric or gas?
Electric is the standard: simpler to install, no gas connection or flue required, and in line with how most kitchens are decarbonising. Gas can be attractive with existing gas infrastructure or unfavourable electricity tariffs. Always assess this together with your installer, since the available connected load often decides it.
Will a Rational actually fit in my kitchen?
Beyond the width of the unit, consider clearance beside and above it, the doorway it has to pass through, floor loading for large models, the electrical supply, the water connection and the drain. The iCombi Pro XS, at 65.5 cm wide, is the smallest option and fits where a 6-1/1 no longer does.
Should I buy a larger model than I need today?
One size up is worth it if you expect growth or already run two batches on peak days. Two sizes up is usually wasted: you pay in purchase price, energy and floor space for capacity you do not use. Often a second small unit alongside an existing machine is more flexible than one very large unit.