Bitrate Calculator OBS: How to Set Streaming Bitrate

This bitrate calculator for OBS works out the video bitrate you should set in OBS Studio based on your upload speed, resolution, and frame rate, and it also estimates the file size of a recording. You enter your internet upload speed (or a target bitrate), the resolution and frame rate you plan to use, and the length of the stream or recording. You get back the recommended video bitrate (in kbps) and the estimated file size or data usage for that session.

Formula

The calculator uses two main formulas: one for the recommended video bitrate and one for the estimated file size.

Video bitrate (kbps) = (Upload speed in Mbps × 1000 × 0.8) / (1 + audio share)

Here, upload speed is in Mbps (megabits per second). The factor 0.8 reserves 20% of your upload for overhead (TCP/IP, WebSocket, and OBS’s own overhead). The audio share is typically 0.15 (15%) of the total bitrate, which is a common assumption for a 160 kbps audio track when the video bitrate is around 1000 kbps or more. For simplicity, this calculator uses a fixed 15% audio share.

File size (MB) = (Video bitrate in kbps + Audio bitrate in kbps) × duration in minutes × 60 / 8 / 1000

This converts the bitrate (in kilobits per second) to megabytes by dividing by 8 (bits to bytes) and then by 1000 (kilobytes to megabytes). The result is the approximate file size for a recording or the total data used for a live stream.

Worked Example

Using the default values from the calculator: upload speed = 10 Mbps, resolution = 1080p, frame rate = 30 fps, and duration = 60 minutes.

Step 1: Calculate the total bitrate budget. 10 Mbps × 1000 = 10,000 kbps. Reserve 20% for overhead: 10,000 × 0.8 = 8,000 kbps.

Step 2: Account for audio. Video bitrate = 8,000 / (1 + 0.15) = 8,000 / 1.15 ≈ 6,956 kbps. Rounded to the nearest kbps, that’s 6,956 kbps.

Step 3: Audio bitrate is set at 160 kbps (a common OBS default).

Step 4: Estimated file size = (6,956 + 160) × 60 × 60 / 8 / 1000 = 7,116 × 3600 / 8000 = 25,617,600 / 8000 = 3,202.2 MB. Rounded to one decimal, that’s 3,202.2 MB, or about 3.2 GB.

So for a 10 Mbps upload, streaming at 1080p30 for 60 minutes, the calculator recommends a video bitrate of about 6,956 kbps and estimates a file size of about 3,202 MB (3.2 GB).

Why Bitrate Matters in OBS

Bitrate is the amount of data transmitted per second in your stream or recording. In OBS Studio, you set the video bitrate in Settings > Output (in Advanced mode) or in the simple output mode’s “Bitrate” field. The right bitrate balances quality and stability:

• Too high: Your stream may buffer, drop frames, or disconnect if your upload speed can’t keep up.
• Too low: The video will look blocky or blurry, especially during fast motion.
• For recordings: Higher bitrate means better quality but larger files. For streaming, the bitrate must fit within your upload capacity.

OBS uses a variable bitrate (VBR) option for recordings, which can help reduce file size, but for streaming, a constant bitrate (CBR) is usually recommended to maintain a stable stream.

How to Choose the Right Bitrate for Your Setup

Choosing the right bitrate depends on your upload speed, resolution, frame rate, and the platform you’re streaming to. Here are general guidelines:

• 720p at 30 fps: 2,500–4,000 kbps is typical.
• 720p at 60 fps: 3,500–5,000 kbps.
• 1080p at 30 fps: 3,500–5,000 kbps (or up to 6,000 on platforms that allow it).
• 1080p at 60 fps: 4,500–6,000 kbps (some platforms cap at 6,000).
• 1440p at 60 fps: 9,000–12,000 kbps.
• 4K at 60 fps: 20,000–40,000 kbps.

These are starting points. If you have plenty of upload speed, you can go higher, but remember that platforms like Twitch have a maximum recommended bitrate (often 6,000 kbps). YouTube allows higher bitrates, especially for 4K. Always check the platform’s current guidelines.

Common Mistakes and Misconceptions

One common mistake is confusing megabits (Mb) with megabytes (MB). Internet speeds are usually in megabits per second (Mbps), but file sizes are in megabytes (MB). 1 byte = 8 bits, so 10 Mbps = 1.25 MB/s. If you set your bitrate to 10,000 kbps (10 Mbps) on a 10 Mbps upload, you’ll have no room for overhead, causing dropped frames.

Another misconception is that higher bitrate always means better quality. Beyond a certain point, the human eye can’t see the difference, and you’re just wasting bandwidth. For 1080p30, 6,000 kbps is already very good; going to 10,000 kbps won’t look noticeably better on most screens.

Also, don’t forget that your upload speed is not the same as your download speed. Use a speed test that measures upload, and run it when your network is otherwise idle. If you have other devices using the internet, the available upload speed will be lower.

Limitations of This Calculator

This calculator provides a solid estimate, but it has limitations:

• It assumes a fixed 20% overhead. In reality, overhead can vary between 10% and 30% depending on your network, OBS settings, and platform.
• It assumes a fixed audio bitrate of 160 kbps. If you use 320 kbps audio (common for music streams), the file size will be slightly larger.
• It doesn’t account for the encoder’s efficiency. x264 (software) at a given bitrate may look better or worse than NVENC (hardware) at the same bitrate, depending on settings.
• It doesn’t consider the complexity of your content. Fast-moving games need more bitrate than static talking-head streams.

Use the result as a starting point, then test your stream and adjust based on the quality and stability you see.

Frequently Asked Questions

What bitrate should I use for OBS streaming?

For 1080p at 30 fps, use 3,500–5,000 kbps. For 1080p at 60 fps, use 4,500–6,000 kbps. If your upload speed is limited, drop to 720p at 30 fps with 2,500–4,000 kbps. Always keep at least 20% of your upload speed free for overhead.

How do I find my upload speed for OBS?

Run an internet speed test and note the upload speed (in Mbps). Make sure no other devices are heavily using the network during the test. Your available upload speed may be lower than the advertised speed, so it’s wise to run the test a few times and use the lowest result.

Does higher bitrate reduce stream lag?

No. Higher bitrate increases the amount of data sent, which can actually cause lag if your upload speed can’t handle it. Stream lag is usually caused by insufficient upload speed, unstable network, or encoder overload, not by low bitrate. Lowering the bitrate can sometimes reduce lag if the network is the bottleneck.

What is the maximum bitrate for Twitch and YouTube?

Twitch recommends a maximum video bitrate of 6,000 kbps for 1080p60. YouTube allows much higher bitrates, up to 40,000 kbps for 4K, but you don’t need that much for most content. Always check the platform’s current guidelines, as they can change.

How do I set bitrate in OBS Studio?

Go to Settings > Output. In Simple output mode, you’ll see a “Bitrate” field under Streaming. In Advanced mode, select the Streaming tab, choose your encoder, and set the “Bitrate” field. For recordings, you can set a separate bitrate in the Recording tab.

Why does my stream drop frames even though my bitrate is below my upload speed?

Dropped frames can occur due to network instability, high latency, or packet loss, not just raw bandwidth. Your upload speed may fluctuate, or your ISP may throttle streaming traffic. Try lowering the bitrate, using a wired connection, or contacting your ISP. Also, check OBS’s stats for dropped frames to see if it’s a network issue.

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in up | Upload speed | Mbps | 10 | 1
in res | Resolution | - | 1080p=1, 720p=2, 1440p=3, 4K=4 | 1
in fps | Frame rate | - | 30=1, 60=2 | 1
in dur | Stream/recording length | min | 60 | 1
out vbit | Recommended video bitrate | kbps | (up * 1000 * 0.8) / (1 + 0.15) | 0
out abit | Audio bitrate | kbps | 160 | 0
out size | Estimated file size | MB | (vbit + abit) * dur * 60 / 8 / 1000 | 1