iPhone & iPad · iOS 17+

How long will
your transfer take?

Enter a file size and connection speed. Get an instant, accurate answer — down to the second.

Download Free

Everything you need,
nothing you don't.

A focused utility that does one thing well.

Instant results

Rolling-digit display updates as you type — days, hours, minutes, seconds.

KB to TB, binary & SI

Toggle between KiB/GiB (OS-accurate) and KB/GB (ISP standard) with one tap.

Speed presets

One-tap chips from 1 Mbps to 10 Gbps. Or type any custom value manually.

Compare two providers

Enter two speeds, see both results side by side. Great for evaluating ISP upgrades.

Real-world accuracy

Sliders for protocol overhead (TCP/IP) and ISP efficiency (advertised vs. actual).

Light, dark & system

Native SwiftUI, iOS 17+. Optimized for iPhone and iPad in portrait mode.

See it in action.

Real transfer times at common speeds.

50 GiB file at 1 Gbps 7 min 24 sec home fiber
50 GiB file at 100 Mbps 1 hr 15 min typical cable
4.7 GB iOS app at 25 Mbps 25 min 4 sec LTE average
33 750 MiB backup at 500 Mbps 9 min 0 sec fast fiber
1 TB archive at 2.5 Gbps 53 min 20 sec 10GbE NAS

Completely private.

DownClock works entirely on-device. No network requests, no data collection, no account required.

The only thing stored locally is your appearance preference (light/dark/system).

0Accounts
0Ads or trackers
0Network requests

Support

Have a question or found a bug? Email us.

Common questions
Why does my result differ from the actual transfer time?
Enable Protocol Overhead and adjust ISP Speed Efficiency for a more realistic estimate. Real speeds are affected by network congestion, server limits, and connection quality.
What's the difference between GiB and GB?
1 GiB = 1,073,741,824 bytes — used by operating systems. 1 GB = 1,000,000,000 bytes — used by ISPs and storage manufacturers. Toggle Binary Units to switch.
Does DownClock work offline?
Yes, completely. All calculations happen on-device with no network connection required.

Privacy Policy

Last updated: May 2026

Overview

DownClock does not collect, store, or transmit any personal data.

Data we collect

None. DownClock does not:

  • Collect names, emails, or any identifying information
  • Track usage, sessions, or in-app behavior
  • Use advertising SDKs or analytics
  • Make any network requests
  • Access contacts, location, camera, or device sensors

Local storage

Only your appearance preference (light/dark/system) is saved locally via Apple's UserDefaults API. This data never leaves your device.

Third-party services

None. DownClock uses no third-party SDKs, crash reporting, or advertising integrations.

Children's privacy

DownClock does not collect data from anyone, including children under 13.

Contact

Questions? support@downclock.app