Adobe的PDF（便携式文档格式(Document Format)）文件在 Internet 上随处使用，用于共享各种文档。PDF文件旨在包含在任何计算机或设备上以相同方式显示的文本格式和图片，无论其类型、硬件或使用的操作系统如何。这就是为什么PDF文件非常适合创建和发送例如法律文件的原因。然而，许多PDF文件的问题是它们通常太大而无法通过电子邮件在互联网上发送或上传到政府机构，这通常会施加文件上传大小限制。这就是为什么在本指南中，我们将回答这个常见问题：“如何使 PDF 文件变小以便上传？” ("How do I make a PDF file smaller so I can upload it?"). 事不宜迟，以下是在任何计算机或设备上免费压缩PDF文件的三种方法：(PDF)
1. 如何在任何平台上使用在线工具使PDF更小，包括(PDF)Windows、macOS、Android、iPhone
无论(Regardless)您使用的是 Windows 10 PC、Mac、Android智能手机，还是 iPhone，这种方法都行得通。您只需要访问 Internet 和 Web 浏览器。在您的计算机或设备上，启动您喜欢的网络浏览器并访问此网站：wecompress.com。
如果您使用的是计算机，请拖放要压缩的PDF文件。(PDF)或者，如果您使用的是智能手机或平板电脑，请单击或点击网站上的大+ plus按钮，浏览您的设备，然后选择PDF文件。
一旦您选择了PDF文件，网站就会开始上传它。等待(Wait)上传完成。
然后，该网站告诉您它正在“压缩您的文件”("Compressing your file")，这意味着它试图使PDF更小。等到(Wait)过程结束。
压缩结束后，网站会告诉您PDF(PDF)文件现在小了多少。然后，在这条信息的正下方，您可以单击或点击“下载(Download)”按钮以获取压缩的较小PDF文件。
但是请注意，某些PDF文件已经被压缩到最大可能，因此您不能使这些PDF文件变得比它们现在更小。在这种情况下，网站会简单地告诉你“文件不能被缩减”("File cannot be reduced")。
提示：(TIP:)还有许多其他网站可以让您将PDF文件缩小，例如smallpdf.com，它得到了我们的荣誉奖。谷歌(Google)搜索提供了很多可供选择的选项。尽管如此，在测试了其中许多之后，wecompress.com 是我们发现的最好和最容易使用的网站。
2. 如何在Windows中使用Free PDF Compressor应用程序使PDF文件更小
如果您有一台Windows计算机，并且您更愿意使用离线工作的桌面应用程序，我们推荐名为Free PDF Compressor的应用程序。除了可以压缩PDF(PDF)文件这一事实之外，它还有其他优点：它是完全免费的个人和非商业用途软件，它还支持不同的压缩设置。
首先从其官方网站获取免费 PDF 压缩器应用程序：(Free PDF Compressor)免费 PDF 压缩器(Free PDF Compressor)。单击或点击“下载镜像”(Download Mirror)按钮并将可执行文件保存在计算机上的某个位置。
运行freepdfcompressor_setup.exe文件并按照安装向导的步骤启动并运行它。然后，使用桌面或开始菜单中的快捷方式打开(Start Menu)Free PDF Compressor。这是你应该看到的：
单击或点击浏览(Browse)以浏览您的Windows计算机并选择要缩小的PDF文件。(PDF)然后，按下打开(Open)按钮。
Free PDF Compressor加载文件并自动为其指定一个输出文件(Output File)。这是创建的较小PDF文件的名称。如果您想使用其他名称并为其保存位置，请单击或点击另存为(Save As)并选择您喜欢的名称。
接下来，在“设置”(Settings)区域中，选择要用于缩小PDF的压缩类型。(PDF)您可以选择：
- 屏幕(Screen)- 低分辨率、仅屏幕查看质量、72 dpi 图像
- 电子书 - 中等分辨率、低质量、150 dpi 图像
- 打印机(Printer)- 高质量、300 dpi 图像
- 印前(Prepress)- 高质量、保色、300 dpi 图像
- 默认(Default)- 用途广泛，可能输出文件更大
Screen和eBook选项可生成最小的 PDF 文件，而Printer和Prepress可为您提供更大但质量更高的PDF文件。(PDF)选择要使用的配置文件后，单击或点击Compress。
压缩完成后，免费 PDF 压缩器(Free PDF Compressor)会让您了解它。单击(Click)或点击确定(OK)，您会发现输出是一个较小的PDF文件，位于您之前选择保存的位置。
就是这样：简单，对吧？
3. 如何在Mac上使用(Mac)Preview应用压缩PDF文件
在Mac上，事情就更简单了。使用“预览(Preview)”应用打开要缩小的PDF文件。(PDF)然后，打开文件(File)菜单并选择导出(Export)。
单击Quartz Filter并从列表中选择“减小文件大小” 。("Reduce File Size")
最后，按保存(Save)并创建较小的 PDF。
提示：(TIP:)我们注意到，当您尝试减小包含扫描图像的PDF文件的大小时，这种方法效果最佳。(PDF)
为什么需要缩小PDF ？
您(Did)是否必须通过电子邮件发送PDF并且它太大了？或者您是否需要将较小的PDF文件上传到不接受其平台上的大文件的机构？我们很好奇您想要缩小PDF文件的原因，所以请不要犹豫，在下面的评论部分告诉我们。
3 ways to make a PDF smaller
Adobe's PDF (Portable Document Formаt) files are used everywhere on the internet for sharing аll kindѕ of documents. PDF files are designed to include text formatting and pictures that are displayed the same way on any computer or device, regardless of its typе, hardware, or operating system used. That's why PDF files are excellent for creating and sending legal documents, for example. The issue with many PDF files, however, is that they are often too large to ѕend on the intеrnet via email or by υрloading them to government institυtions, which often impose file upload size limits. That's why, in this guide, we're going tо answer this common question: "How do I make a PDF file smaller so I can upload it?". Without further ado, here are three ways to compress a PDF file, for free, on any computer or device:
1. How to make a PDF smaller using an online tool, on any platform, including Windows, macOS, Android, iPhone
Regardless of whether you're using a Windows 10 PC, a Mac, an Android smartphone, or even an iPhone, this method just works. You only need to have internet access and a web browser. On your computer or device, launch the web browser you prefer and go to this website: wecompress.com.
If you're using a computer, drag and drop the PDF file you want to compress. Alternatively, if you're using a smartphone or a tablet, click or tap on the large + plus button from the website, browse through your device, and select the PDF file.
As soon as you select the PDF file, the website starts uploading it. Wait for the upload to finish.
Then, the website tells you that it's "Compressing your file", which means that it tries to make the PDF smaller. Wait until the process is over.
Once the compression is over, the website tells you how much smaller the PDF file is now. Then, right under this piece of information, you can click or tap on the Download button to get your compressed, smaller PDF file.
Note, however, that some PDF files are already compressed to maximum possible, so you can't make those PDF files smaller than they already are. In such a situation, the website tells you simply that "File cannot be reduced".
TIP: There are many other websites that let you make PDF files smaller, like smallpdf.com for example, which gets an honorable mention from us. A Google search renders plenty of options to choose from. Still, after testing many of them, wecompress.com was the best and easiest to use website that we've found.
2. How to make PDF files smaller in Windows, using the Free PDF Compressor app
If you have a Windows computer, and you'd rather use a desktop app that works offline, we recommend the one called Free PDF Compressor. Besides the fact that it can compress PDF files, there are also other great things about it: it's completely freeware both for personal and non-commercial use, and it also supports different compression settings.
Start by getting the Free PDF Compressor app from its official website: Free PDF Compressor. Click or tap on the Download Mirror button and save the executable file somewhere on your computer.
Run the freepdfcompressor_setup.exe file and follow the steps of the installation wizard to get it up and running. Then, open Free PDF Compressor using its shortcut from your desktop or Start Menu. This is what you should see:
Click or tap on Browse to navigate through your Windows computer and select the PDF file that you want to make smaller. Then, push the Open button.
Free PDF Compressor loads the file and automatically designates an Output File for it. That's the name of the smaller PDF file that's created. If you'd rather use another name and save location for it, click or tap on Save As and choose the ones you prefer.
Next, in the Settings area, select the type of compression you want to use to make the PDF smaller. You can choose between:
- Screen - low resolution, screen-view-only quality, 72 dpi images
- eBook - medium resolution, low quality, 150 dpi images
- Printer - high quality, 300 dpi images
- Prepress - high quality, color preserving, 300 dpi images
- Default - a wide variety of uses, possibly larger output file
The Screen and eBook options result in the smallest PDF files, while the Printer and Prepress get you larger PDF files but with higher quality. Once you've selected the profile you want to use, click or tap on Compress.
As soon as the compression is done, Free PDF Compressor lets you know about it. Click or tap OK and you'll find the output to be a smaller PDF file, in the location where you chose to save it earlier.
That's it: simple, right?
3. How to compress a PDF file using the Preview app on a Mac
On a Mac, things are even more simple. Open the PDF file that you want to make smaller, using the Preview app. Then, open the File menu and select Export.
Click on Quartz Filter and select "Reduce File Size" from the list.
Finally, press Save and your smaller PDF is created.
TIP: We noticed that this works best when you're trying to reduce the size of PDF files that contain scanned images.
Why did you need to make your PDF smaller?
Did you have to send a PDF via email and it was simply too big for that? Or did you need to upload a smaller PDF file to an institution that doesn't accept large files on its platform? We're curious about the reasons you had for wanting to make PDF files smaller, so don't hesitate to let us know in the comments section below.
