Fabric CU Usage

[tolgakurt]

Hi everyone.

I have some confusion about the capacity usage on Fabric.

I made a simple page where I can track my daily CU usage via Fabric Capacity Metric app. This page includes daily capacity usage and hourly distributions.

As far as I know, the amount of capacity I can use per day is (I am using Trial capacity. It provides 1920 CUs in 30 seconds. I calculate daily usage as follows: 1920x2x60x24 = ~5.5M CU per day)

On Fabric Capacity MEtric, it shows that I used 288k cU on 2025/05/26. In other words, about 5% of the capacity provided to me by the FT1 package (5.5M CU / 288K CU) is used, but in the other metric, cumulative CU, this ratio is 216%.

What is wrong here?

SS from report page:

[v-tsaipranay]

Hi @tolgakurt ,

Thanks for reaching out to the Microsoft Fabric Community. Also thank you @burakkaragoz  for your inputs.

You are correct the CUDetail table is the right place to look for per-interval CU usage, and aggregating from there gives you a good picture of daily CU consumption.

Regarding your main question:

• During the trial period (FT1), there is no billing, regardless of spikes or daily usage levels.
• In general Fabric capacity (including paid SKUs), you are not billed based on how much CU you consume on a given day.
• Instead, billing is based on the SKU tier (e.g., F64, F128) that your capacity is assigned to, and it’s charged per hour.
• Short-term usage spikes that do not cause capacity scale-up or reconfiguration will not trigger additional charges.

So, as long as you stay within your assigned capacity tier (even with some peak usage moments), there’s no extra cost beyond your base SKU rate. Monitoring daily average usage is still a good practice for long-term planning and sizing, especially when moving beyond the trial.

I hope this gives you an idea, if you need any further assistance, feel free to reach out.

If this post helps, then please give us Kudos and consider Accept it as a solution to help the other members find it more quickly.

Thankyou.

[burakkaragoz]

Merhaba @tolgakurt ,

Evet, bu metrikler ilk başta kafa karıştırıcı olabiliyor. Buradaki kritik fark şu: günlük CU kullanımı ve kümülatif CU farklı mantıklarla hesaplanıyor.

Senin günlük kullanım hesabın (1920 x 2 x 60 x 24) FT1 trial için doğru — bu sana teorik olarak günlük maksimumu veriyor. Ama cumulative CU metriği günlük olarak sıfırlanmaz. Bu metrik daha çok birikimli bir toplam gibi çalışır (raporun yapılandırmasına göre 7 ya da 30 günlük olabilir).

Yani 216% gibi bir oran görüyorsan, bu büyük ihtimalle birden fazla günün toplamı. Bu yüzden 26 Mayıs’taki 288K CU ile karşılaştırınca şişirilmiş gibi duruyor.

Cumulative CU görselindeki zaman aralığı filtresini kontrol etmeni öneririm. Eğer sadece tek bir günü göstermiyorsa, karşılaştırma yanıltıcı olur.

İstersen rapor filtrelerini nasıl ayarlayabileceğini ya da o görselin arkasındaki DAX formülünü birlikte inceleyebiliriz.

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Yeah this can be a bit confusing at first. The key thing here is that daily CU usage and cumulative CU are calculated differently.

Your daily usage calc (1920 x 2 x 60 x 24) is correct for FT1 trial — that gives you the theoretical max per day. But the cumulative CU metric doesn’t reset daily. It’s more like a rolling total or a sum over a longer period (like 7 or 30 days depending on the report config).

So when you see 216%, it’s probably summing up multiple days of usage, not just 26th May. That’s why it looks inflated compared to your daily usage.

You might wanna double-check the time range filter on the cumulative CU visual. If it’s not scoped to a single day, it’ll throw off the comparison.

Let me know if you want help adjusting the report filters or validating the DAX behind those visuals.

If my response resolved your query, kindly mark it as the Accepted Solution to assist others. Additionally, I would be grateful for a 'Kudos' if you found my response helpful.

[tolgakurt]

Merhaba.

Öncelikle yanıtın için teşekkür ederim 🙂

Aslında bu rapor için farklı bir kaynak kullanmadım. Fabric Capacity Metrics app üzerinden aynı verisetini kullanarak kendime yeni bir sayfa yaptım ve herhangi bir ek dax hesaplaması yapmadım. Default olarak hesaplanan metrikler üzerinden ilerledim.

Günlük kullanılan CU dikkate almak için CUDetail sayfasındaki toplam CU almam yeterli olacaktır o zaman doğru anladıysam.

Buradaki amacım şu : Şuan test aşamasındayım ve günlük ortalama kullanılan kapasiteyi bulmak istiyorum. Günün bazı saatlerinde kapasite kullanımları fazla olabiliyor ve threshold'u aşıyor. Ancak günlük toplama baktığım zaman kapasitenin maximum sınırına ulaşmıyorum. Bu durumda paket ücreti haricinde ekstra bir faturalandırma oluyor mu ? Yoksa günlük maximum kapasiteyi doldurmadığım sürece ek bir ücret ödememe gerek kalmayacak mı ?

Teşekkürler.

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Hello.

First of all, thank you for your answer.

Actually, I did not use a different source for this report. I created a new page for myself using the same dataset from the Fabric Capacity Metrics app and did not make any additional dax calculations. I proceeded with the metrics calculated by default.

If I understand correctly, it will be enough to get the total CU on the CUDetail page to take into account the daily used CU.

My goal here is as follows: I am currently in the testing phase and I want to find the daily average used capacity. Capacity usage can be high at some hours of the day and exceeds the threshold. However, when I look at the daily total, I do not reach the maximum limit of the capacity. In this case, is there an extra billing other than the package fee? Or will I not have to pay an additional fee as long as I do not fill the daily maximum capacity?

Thank you.

[burakkaragoz · Accepted solution]

Rica ederim, diğer kişilerin faydalanması için bundan sonrasına ingilizce devam edeceğim. 😊 

Yes, you're right. If you're using the CUDetail page and summing up the CU values per day, that gives you a good estimate of daily usage. No need for custom DAX if you're sticking with the default metrics.

Now about the billing part:

• Threshold breaches (like hourly spikes) don’t automatically mean extra charges.
• What matters is whether your total daily CU usage exceeds the daily quota (in your case, ~5.5M CU for FT1).
• As long as your daily total stays under that limit, you won’t be billed extra, even if some hours spike above the average.

So you’re safe unless your daily usage consistently goes over the quota. But it’s smart to monitor those spikes — they can become an issue if they start pushing your daily total up.