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Axiom Lab

Video File Size & Bitrate Calculator (1080p, 4K, H.264, H.265, ProRes)

Estimate exact video file size (MB/GB) and target bitrate (Mbps) before exporting a 15-second product TVC, a 60-second pitch video, or a 9:16 vertical reel for email, Slack, Shopify, or WeChat.

By Axiom Lab · Published · Updated

Standard presets:
Estimated H.264 MP4 size
92.2 MB
Estimated H.265 size
53.5 MB
Aspect ratio & 90% title-safe
16:9 (1728×972)

Channel attachment limit & legibility check

• Standard Email Attachment (< 25 MB): OVER LIMIT ⚠️ Share via link or lower bitrate
• WeChat / Slack Direct File (< 100 MB): PASS ✅ Instant mobile playback
• Title-Safe Margin (90% inner frame): 1728 × 972 px (margin 96px / 54px)
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How video file size is calculated from bitrate, resolution, and duration

Uncompressed pixel dimensions do not determine final MP4 file size on their own—total bitrate (video Mbps + audio kbps) multiplied by duration does. The exact formula is File Size (MB) = ((Video Bitrate in Mbps + Audio Bitrate in Mbps) × Duration in Seconds) ÷ 8, where dividing by 8 converts megabits (Mb) into megabytes (MB).

Switching from H.264 (AVC) to H.265 (HEVC) cuts file size by roughly 35–45% at equivalent visual quality, whereas Apple ProRes 422 intermediate masters require 120–147 Mbps at 1080p30 (roughly 1.1 GB per minute). Use the calculator above to verify whether your export will fit under Slack, Discord, WeChat, or email attachment limits.

Exporting lightweight 15-second TVC product videos and 60-second pitch films

If you are embedding a 15-second product video on a Shopify/Amazon listing or attaching a 60-second pitch film in an investor email link, oversized files cause buffering on mobile networks and kill conversion rates.

Axiom Lab Studio (/create/product for 15s TVC product films and /create/project for 60s pitch films) automatically masters 1080p deliverables at an optimal 8–12 Mbps H.264 profile—keeping a 15-second product TVC under 18 MB and a 60-second project film under 75 MB with crisp typography.

Video Bitrate & File Size Reference Table (15s TVC, 60s Pitch Video & 1-Min Master)

Resolution & FPSCodec ProfileRecommended Bitrate15s Product TVC Size60s Pitch Video Size
1080p (1920×1080) @ 30fpsH.264 (Web / Social MP4)8 Mbps + 192 kbps AAC~15.4 MB~61.4 MB
1080p (1080×1920 9:16) @ 30fpsH.265 / HEVC (Mobile Reel)5 Mbps + 192 kbps AAC~9.7 MB~38.9 MB
4K UHD (3840×2160) @ 30fpsH.264 (High-Profile Master)35 Mbps + 320 kbps AAC~66.2 MB~264.9 MB
1080p (1920×1080) @ 30fpsApple ProRes 422 (.mov)147 Mbps + PCM Audio~275.6 MB~1.10 GB

Frequently asked questions

What is the exact formula to convert Mbps bitrate and duration into megabytes (MB)?

Because 1 Byte equals 8 bits, divide your total bitrate in megabits per second (Mbps) by 8 to get megabytes per second (MB/s), then multiply by duration in seconds: File Size (MB) = (Total Mbps ÷ 8) × Seconds. For example, an 8 Mbps video running 60 seconds is (8 ÷ 8) × 60 = 60 MB.

How large should a 15-second product video or 60-second pitch video be for fast web playback?

For instant loading on product pages, trade-show loops, and mobile chats, keep a 15-second 1080p product video between 10 MB and 20 MB (5–10 Mbps H.264), and a 60-second 1080p pitch film between 45 MB and 75 MB.

Why does frame rate (60fps vs 30fps) increase video file size?

Doubling the frame rate from 30fps to 60fps doubles the number of frames encoded per second, requiring roughly 1.5× to 1.8× higher bitrate to maintain the same per-frame compression quality without macroblocking.

Can I generate a properly compressed 15-second product TVC or 60-second pitch video directly?

Yes. Click the Studio button to bring your brief into Axiom Lab (/create/product for 15-second Cinematic, Tech, or Lifestyle product TVCs, or /create/project for 60-second project films).

Expand platform upload file-size limits (WeChat, Slack, Shopify, Amazon, LinkedIn, Email)

Platform Video Upload Limits & Recommended Export Settings

Before exporting your video or choosing a delivery channel, check the maximum file size and bitrate ceiling enforced by major messaging apps, e-commerce storefronts, and social feeds.

Matching your target platform's native bitrate prevents aggressive server-side re-compression that blurs small UI text and subtitle edges.

Distribution ChannelMax File Size LimitPreferred Aspect RatioOptimal Bitrate (1080p)Recommended Axiom Lab Workflow
Shopify / Amazon Product Main Video500 MB (best under 25 MB for speed)16:9 or 1:1 / 9:166–10 Mbps H.264 MP4Product Video (/create/product · 15s TVC)
WeChat Chat / Channels (9:16 Card)25 MB (direct chat) / 2 GB (Channels)9:16 Vertical (1080×1920)5–8 Mbps H.264 MP4Founder Card (/create/name_card · 30–90s)
Slack / Discord / Deal-Room Clip50 MB–1 GB (depending on tier)16:9 Landscape (1920×1080)8–10 Mbps H.264 MP4Project Video (/create/project · 60–90s)
TikTok / Instagram Reels / Shorts287 MB–4 GB9:16 Vertical (1080×1920)8–12 Mbps H.264 MP4Expert Interview Reel (/create/profile_card)

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