SaaS Metrics 2.0 · Definitions

This page is a supplement to the the SaaS Metrics 2.0 blog post.

这一页是 SaaS Metrics 2.0 主篇的配套字典。

It provides detailed definitions for each of the key metrics used in that post.

它给出主篇里每一个核心指标的精确定义。

I am often asked for the details of how to compute the various elements, such as CAC and LTV.

我经常被问到:CAC、LTV 这些细节具体怎么算?

This post gives the formulae.

这篇文章给出公式。

CAC is defined as follows:

CAC 的定义如下:

There is a problem with using this formula in the early days, as you may several expensive people in the team that should scale to handle a far number of customers as you grow.

早期使用这个公式会有问题:团队里可能已经有几个高薪 hire,他们的产能其实是为未来扩张准备的——但现在客户量还小。

In that case, your CAC will be too high.

在这种情况下,你算出来的 CAC 会偏高。

I suggest doing a very simple adjustment to the Sales & Marketing expenses to take only a portion of those salaries and expenses in the early days.

我建议做一个非常简单的调整:早期只把销售和市场费用中的一部分计入。

That will give a better indication of how CAC will look in the future when you are at scale.

这能让你看到"未来规模化后 CAC 大致长什么样"——更有参考价值。

If you start with a cohort of 100 customers and apply a constant churn rate every month, you'll get an exponential decay, as shown in the following graph (which uses a 3% monthly churn rate):

如果一组 cohort 起步有 100 个客户,每月按一个恒定比率流失,衰减会是指数型的——下图用 3% 月流失为例:

Mathematically this can be simplified to the following formula to find the average Customer Lifetime:

数学上,这条曲线可以化简成下面这个简单公式来求平均"客户生命周期":

Note that if the Customer Churn rate is a monthly % or yearly %, then the Customer Lifetime will be for the same time period.

注意:Churn 率是月度百分比时,Customer Lifetime 就是月数;是年度百分比时,Customer Lifetime 就是年数——单位必须对齐。

Here is a monthly and annual example to illustrate the point:

下面是月度和年度两个例子来说明这一点:

a) If the Monthly customer churn rate is 3%, then the Customer Lifetime will be 1 / 0.03 which is 33 months.
b) If the Annual customer churn rate is 20%, then the Customer Lifetime will be 1 / 0.20 which is 5 years.

a) 月度客户流失率 3% → Customer Lifetime = 1/0.03 = 33 个月。
b) 年度客户流失率 20% → Customer Lifetime = 1/0.20 = 5 年。

For a more detailed blog post dedicated to the topic of how to calculate LTV, see the following blog post: What's your TRUE customer lifetime value (LTV)? – DCF provides the answer.

关于 LTV 怎么算,有一篇更详尽的专文:What's your TRUE customer lifetime value (LTV)? – DCF provides the answer。

The following provides a simple intro to the topic:

下面是对这个话题的一个简单入门:

In the situation where all customers have roughly the same ARPA, and where there is no expansion revenue expected over the lifetime of a customer, you can use this simple formula:

在所有客户 ARPA 大致相同、且预期生命周期内没有 expansion 收入的情况下,可以用这个简单公式:

which can also be expressed as follows:

也可以表达成下面这样:

Once again if ARPA is monthly, the churn rate should be monthly.

再次强调:ARPA 是月度的话,churn 也要用月度。

However in situations where you have widely differing ARPA across the customer base, this would not take into consideration the difference between losing a high value customer versus a low value customer.

但如果你的客户群里 ARPA 差异非常大,上面这个公式就没法区分"丢一个大客户"和"丢一个小客户"的差别。

So a more accurate formula would be:

所以一个更准确的公式是:

In the specific situation where you expect ARPA to change over the lifespan of the customer due to expansion revenue, this simple version of the formula will not work.

如果你预期客户的 ARPA 会随生命周期变化(因为有 expansion 收入),前面这个简单公式就不适用了。

We ran into this situation with ZenDesk, where there is a pretty reliable increase in revenue over the life of a customer.

我们在 ZenDesk 就遇到过这种情况——客户生命周期内,收入会比较稳定地增长。

Here's a graph showing what would happen if you had a cohort of 100 customers that initially started paying you $100 a month, but increased their payment by $5 every month. The monthly Customer Churn Rate is 3%:

下面这张图展示了这样一个场景:一组 100 个客户 cohort,起初每月付 $100,之后每月增加 $5;月度客户流失率 3%:

As you can see the expansion revenue initially is greater than the losses from churn, but over time the churn takes over and brings down the value of that cohort.

可以看到:初期 expansion 收入大于流失损失,但随着时间推移,流失逐渐占主导,把 cohort 价值拉下来。

I asked my partner, Stan Reiss, to help with the math to calculate LTV in this more complex situation.

我请了 Matrix 的合伙人 Stan Reiss 帮我推这种更复杂情况下 LTV 的公式。

Here is what he came up with:

他给出的版本如下:

Variables:
a = initial ARPA per month × GM %
m = monthly growth in ARPA per account × GM% (note this is a $ figure, not a percentage)
c = Customer Churn Rate % (in months)

变量:
a = 初始月 ARPA × GM%
m = 每月每账户 ARPA 增长 × GM%(注意:这是美元数,不是百分比)
c = 月度客户流失率 %

(This formula makes an assumption that revenue increases at a roughly fixed rate every month for the entire lifetime of the customer.

(这个公式假设:整个生命周期内,收入每月按一个大致固定的速率增长。

That probably doesn't hold true for many SaaS businesses, but the goal is to get a rough idea, not to have the absolute perfect answer.)

这对很多 SaaS 公司其实不成立——但目标是拿到一个大致估值,不是绝对精确答案。)

But there are other complexities such as as the following:

还有其他更复杂的情况,比如:

· Your churn doesn't follow an exponential decay curve
· Your customers don't follow a simple linear revenue expansion

· 你的流失不遵循指数衰减曲线
· 你的客户不是简单的线性扩展

To handle these more complex cases, please refer to this more detailed post on how to calculate LTV: What's your TRUE customer lifetime value (LTV)? – DCF provides the answer.

要处理这些更复杂的情况,请参考另一篇详细讨论 LTV 的文章:What's your TRUE customer lifetime value (LTV)? – DCF provides the answer。

Our guideline for a successful SaaS business is that this number should be higher than 3.

我们对一家成功 SaaS 公司的经验法则是:这个比值应该 > 3。

(The guideline assumes you are using the simpler LTV formula that does not include a Gross Margin adjustment, and that you have a Gross Margin of 80% or higher.)

(这条经验法则假设你用的是不含 GM 调整的简单 LTV 公式,且毛利率在 80% 或以上。)

To be perfectly accurate, this should include a Gross Margin adjustment as follows:

要做到完全准确,应该加上 Gross Margin 调整,如下:

Months to recover CAC gives you a very good sense of how much capital you will burn if you start growing the business.

Months to recover CAC 能让你很清楚地看到:开始扩张生意时你会烧掉多少现金。

The lower this number, the less capital you will consume.

这个数字越低,你消耗的资本越少。

In our guidelines provided in the SaaS Metrics 2.0 Blog post, we suggest that Months to Recover CAC should be less than 12 months.

我们在 SaaS Metrics 2.0 主篇里给出的经验法则是:Months to Recover CAC 应当少于 12 个月。

That guideline was written back in 2011, when it was hard to raise capital.

这条法则写于 2011 年——当时融资还很难。

Since then the investment community has realized the power of the SaaS business model, and many SaaS companies have gone public and performed well.

从那以后,投资圈认识到了 SaaS 商业模式的威力,很多 SaaS 公司也上市并表现良好。

As a result, it is now possible to raise much larger amounts of capital, and therefore you can afford to have a longer time to recover CAC than just 12 months.

所以现在你能融到的资金量大得多——CAC 回收期可以接受比 12 个月更长。

In many enterprise businesses, where there is a Land and Expand model, Months to recover CAC can be around 20 months, and the model works fine.

很多企业级生意是 Land-and-Expand 模式——CAC 回收期 20 个月左右照样跑得通。

In practice, it is very rare to find Months to recover CAC as less than 12.

实际操作中,很少见到 CAC 回收期能压到 12 个月以内。

If you are able to manage the business to have good values for these metrics, you will know that you are building a healthy SaaS business.

如果你能把这四个指标都管到好的水平上,就能确认自己在建一家健康的 SaaS 公司。

Sales Efficiency and the "Magic Number" metrics are different ways of evaluating pretty much the same thing as Months to Recover CAC.

Sales Efficiency 和 "Magic Number"——它们和 Months to Recover CAC 衡量的几乎是同一件事,只是表达方式不同。

The thought process behind both of these metrics is to figure out how efficient is a business's sales and marketing spend.

这两个指标背后的思考都是:这家公司在销售和市场上的支出有多高效?

To do that these metrics ask the question: for every dollar of spend on sales and marketing, how much new revenue does that bring in?

它们用同一个问题来衡量:每花 1 美元销售市场费用,带来多少新增收入?

There are two versions of Sales Efficiency, Gross and Net.

Sales Efficiency 有两个版本:Gross(总)和 Net(净)。

Gross Sales Efficiency simply looks at Gross New ARR (which does not include churn), while Net Sales Efficiency measures Net New ARR, which is reduced by Churn.

Gross Sales Efficiency 只看 Gross New ARR(不算流失);Net Sales Efficiency 用 Net New ARR(扣掉流失之后)。

Here are the two formulae:

两个公式如下:

Gross New ARR = New ARR from new customers + Expansion ARR from existing customers.

Gross New ARR = 新客户带来的 New ARR + 存量客户带来的 Expansion ARR。

You could think of this as the output from sales and marketing without paying any attention to how well the company does at retaining and growing those customers.

你可以把它理解为:销售和市场的"产出"——完全不考虑公司在留存和扩展这些客户上做得好不好。

We use the prior quarters spend on sales and marketing with the thought that there is likely to be a delay between the spending of money and effort on sales and when the deal closes.

我们用上一季度的销售市场支出——因为花钱、做销售动作和真正成交之间往往有时间差。

However if your business has a short sales cycle you could use the same quarter's sales and marketing spend.

但如果你的销售周期很短,可以直接用同一季度的 S&M 支出。

Net New ARR = New ARR from new customers + Expansion ARR from existing customers – Churned ARR.

Net New ARR = 新客户 New ARR + 存量客户 Expansion ARR − 流失 ARR。

So Net Sales Efficiency measures not just Sales and Marketing, but also how effective the company is at retaining and growing those customers.

所以 Net Sales Efficiency 不只衡量销售市场,还衡量公司在留存和扩展客户上做得有多好。

The shortcoming of Sales Efficiency is that it does not take into consideration Gross Margin %.

Sales Efficiency 的一个短板,是它没考虑毛利率。

A business with a high gross margin of say 80% is a dramatically better business than a business with the same Sales Efficiency number but a Gross Margin % of only 40%.

一家毛利 80% 的公司,跟一家 Sales Efficiency 数字相同但毛利只有 40% 的公司——前者好得多。

If we ignore Gross Margin, a Sales Efficiency of 1, implies that Months to recover CAC is 12 months.

忽略毛利的话,Sales Efficiency = 1 意味着 Months to recover CAC = 12 个月。

As Sales Efficiency drops to 0.5, your Months to recover CAC increases to 24 months.

Sales Efficiency 降到 0.5,Months to recover CAC 就升到 24 个月。

I tend to prefer "Months to recover CAC" as the name of the metric is self-explanatory, which makes everyone clear what it is that you are measuring.

我个人更喜欢 "Months to recover CAC" 这个名字——它本身就是自解释的,大家一听就知道你在测什么。

It also has one other advantage, which is that it takes into consideration Gross Margin %.

它还有另一个优势:加 GM 调整版本能把毛利考虑进去。

The one problem with both Months to recover CAC and Sales Efficiency is that public SaaS companies do not reveal these metrics.

Months to recover CAC 和 Sales Efficiency 这两个指标都有一个问题:公开上市的 SaaS 公司不会披露它们。

Given that it would be nice to find a way to create a standardized metric that could be used to benchmark all SaaS companies, Scale Ventures came up with the idea of modifying Sales Efficiency to create what they called the Magic Number.

既然想要一个能对所有 SaaS 公司做横向对比的标准化指标,Scale Ventures 就改造 Sales Efficiency 创造了他们称之为 Magic Number 的指标。

This is very similar to Net Sales Efficiency.

这跟 Net Sales Efficiency 非常相似。

It replaces Net New ARR in the current quarter, with the increase in GAAP Revenue in the current quarter multiplied by 4 to bring it closer to ARR (which is an annual number, not a quarterly number).

它把"当季 Net New ARR"替换成"当季 GAAP Revenue 增量 × 4"——因为 ARR 是年化数字,而季度收入要 × 4 才大致对应。

Anyone is now able to compute a metric that is now very close to Net Sales Efficiency using data that all public SaaS companies report, and therefore we have a standardized benchmark.

这样任何人都能用公开 SaaS 公司披露的数据,算出一个非常接近 Net Sales Efficiency 的指标——于是我们就有了标准化的横向对比基准。

There are two shortcomings of the Magic Number that are worth knowing:

Magic Number 有两个值得知道的短板:

1. It does not take into consideration Gross Margin %. We have already pointed out that if you have low gross margins, you really need to have much higher sales efficiencies to make up for that.

1. 它没考虑毛利率。我们前面提过——毛利低的话,你需要远高的销售效率才能补回来。

2. It does not take into consideration the mix between Subscription Revenue and Services Revenue, which is far less valuable, and typically lower margin.

2. 它没区分订阅收入和服务收入——后者价值低得多、毛利也通常低很多。

In a traditional, non-SaaS, software business, Bookings are one of the most important metrics.

在传统的、非 SaaS 的软件生意里,Bookings 是最重要的指标之一。

However it turns out that in a SaaS business, you need to look closely at what is the right way to measure Bookings.

但在 SaaS 生意里,Bookings 怎么衡量才合适,需要仔细推敲。

To understand the nature of the problem, let's say that in one month we sign two deals: both sign up for the same product, at $1,000 per month, but one signs up for one month commitment, and the other signs up for 12 months.

要理解问题本质,设想这样一个例子:某月签了两单——都是 $1,000/月的同一个产品,但一个客户只签 1 个月,另一个签 12 个月。

In that situation, how should you compute Bookings?

这种情况下,Bookings 怎么算?

An interesting thing can happen with those same two customers: the customer who signed up for only one month at a time, might stay with you for four years, but the customer who signed up for one year, might leave at the end of that one year.

这两个客户之后可能发生意想不到的事:那个按月签的客户可能跟你待 4 年;而那个一次性签了 12 个月的客户,可能合同到期就走。

So what initially looked like the more valuable booking turns out over time to be the less valuable booking.

所以"看起来更有价值"的那单,长期来看反而价值更低。

This is the most important metric to run a SaaS business by from month to month, quarter to quarter.

这是 SaaS 公司月度、季度运营时最重要的指标。

It takes in to consideration most of the key elements that you need to drive to grow your business:

它把你推动业务增长所要关注的大部分核心要素都考虑了进去:

Net New ARR is the sum of the following three components:

Net New ARR 由下面三个分量之和构成:

To really understand what is going on in your SaaS Business, you should look at the following components:

要真正搞清楚你 SaaS 公司里发生了什么,该看的是下面这几个分量:

a) What happened with new customers:
· New ARR from new customer contracts

a) 新客户那边发生了什么:
· 新客户合同带来的 New ARR

b) What happened in your installed base:
· Renewals
· Churned ARR
· Expansion bookings

b) 存量客户那边发生了什么:
· 续约(Renewals)
· 流失 ARR
· 扩展签单

The sum of all of the above:
· Net New ARR

三者之和:
· Net New ARR

Since there can be some confusion around the difference between bookings, billings and revenue, here is a simple example to help clarify them:

Bookings、Billings、Revenue 之间的差别经常让人困惑——下面这个简单例子能把它们讲清楚:

Imagine you signed a new contract with a customer with a one year term, specifying that you provide your service to them for $1,000 per month, with an upfront payment of six months:

假设你跟一个客户签了 1 年合同——$1,000/月,客户预付 6 个月:

· Your bookings would be $12,000 (the entire contract value)
· You would bill $6,000 in the first month, then $1,000 per month from the seventh month onwards.
· You would recognized $1,000 in revenue for each month of the contract. (This is dictated by GAAP accounting policy.)

· Bookings = $12,000(整个合同价值)
· 第 1 个月开 $6,000 账单,第 7 个月开始每月开 $1,000
· Revenue 每月只确认 $1,000——共 12 个月(GAAP 会计准则规定)

For the example above, the balance sheet and income statement impact of these items is as follows:

上面这个例子里,这些项目对资产负债表和利润表的影响如下:

· Bookings do not affect either the balance sheet or the income statement.

· Bookings 既不影响资产负债表,也不影响利润表。

· When you bill $6,000 in the first month, but can only recognize $1,000 in revenue (income statement), and the other $5,000 goes into deferred revenue on the balance sheet (a liability).

· 第一个月开了 $6,000 账单,但 revenue 只能确认 $1,000(进利润表)——另外 $5,000 进资产负债表的 Deferred Revenue(一个负债项)。

· Each month thereafter until another $1,000 can be recognized as revenue (income statement), and that reduces the deferred revenue liability on the balance sheet.

· 之后每个月,$1,000 转成 revenue(进利润表),同时资产负债表上的 Deferred Revenue 负债减少 $1,000。

The following shows the metrics to understand Churn:

下面是理解流失(Churn)相关的指标: