NPS Calculator: Net Promoter Score With Margin of Error

This NPS calculator works two ways: type in how many promoters, passives and detractors you have, or paste the raw scores straight from your survey. Unlike a basic NPS score calculator, this net promoter score calculator also tells you how far you can trust the result and how many promoters you’re short of your target.

How to calculate NPS with the calculator

1. Pick how your data looks

   Done

   If your survey tool already gives you the three groups, keep “I know how many are in each group.” If you have a column of scores in Excel or Google Forms, choose “Paste the 0-10 scores.”

2. Enter the counts or paste the scores

   Done

   Scores can go one per line or separated by commas. Anything that isn’t a whole number from 0 to 10 gets ignored, and the calculator tells you how many values it dropped. You’ll also see the score distribution in a chart.

3. Read the result

   Done

   Your NPS shows up big and on the gauge, from −100 to 100, with the share of each group and the margin of error.

4. Set a target

   Done

   Type where you want to land in “Target NPS” and you’ll see how many new promoters you need, or how many detractors you’d have to win over.

NPS formula and a worked example

Net Promoter Score comes from one question: on a 0 to 10 scale, how likely are you to recommend us to a friend or colleague? Fred Reichheld of Bain & Company introduced it in Harvard Business Review in December 2003, in “The One Number You Need to Grow.” The NPS calculation is a simple subtraction:

NPS = % promoters (9 and 10) − % detractors (0 to 6)

Passives (7 and 8) don’t add or subtract, but they do count in the total. That’s why the score runs from −100 (all detractors) to 100 (all promoters). Here’s how to calculate NPS with the example the calculator loads:

Group	Responses	Share
Promoters	120	60%
Passives	50	25%
Detractors	30	15%
Total	200	NPS = 60 − 15 = 45

If the score points to something you need to fix, take it into your SWOT analysis as a strength or a weakness, with the number next to it.

NPS survey questions: wording, follow-ups and timing

The NPS question never changes: “On a scale of 0 to 10, how likely are you to recommend [company] to a friend or colleague?” An open follow-up comes right after it: “What is the main reason for your score?” Those are your NPS survey questions. The rest is timing, and it gives you two types of NPS:

• Transactional NPS: sent after a specific interaction, like a delivery or a support chat. It measures that moment.
• Relational NPS: sent to your whole customer base every so often, with no event behind it. It measures the overall relationship.

Say you run an online store: send the transactional survey three days after delivery and the relational one every six months to everyone who has bought. Keep the question and the channel identical each time so scores stay comparable, and calculate each type separately.

NPS vs CSAT vs CES: which metric to use

NPS measures how likely people are to recommend you. CSAT and CES measure other things, so don’t swap them.

Metric	Typical question	Typical scale	Best for
NPS	How likely are you to recommend us?	0 to 10	Loyalty and word of mouth
CSAT	How satisfied were you with this order?	1 to 5	One specific moment
CES (Customer Effort Score)	How easy was it to get this done?	Disagree to agree	Support, returns, checkout

CSAT tells you whether today went well. NPS tells you whether people would come back and speak well of you. A customer can rate an order 5 on CSAT and still never recommend you because of price or shipping times. So use both: CSAT after each order, NPS every few months. If the pain is the process itself (returns, payments, booking), add CES.

NPS margin of error: how many responses you need

An NPS from 20 responses isn’t worth the same as one from 1,000. Most free NPS calculator tools skip this part. This one gives you the 95% confidence interval using the adjusted-Wald method that Jim Lewis and Jeff Sauro (MeasuringU) recommend for NPS. It adds 3 to the total and 0.75 to both promoters and detractors. Then it runs the standard-error formula on the +1, 0 and −1 scores.

Same mix as the example (60% promoters, 15% detractors):

Responses	Margin of error	True NPS likely between
20	±31	+8 and +70
200	±10	+34 and +55
1,000	±5	+40 and +49

Put simply: if your NPS goes from 40 to 46 on 200 responses, you can’t tell yet whether you improved. Under 30 responses, the calculator flags the result as a rough read.

How many promoters you need to hit a target NPS

If you add k new promoters and nothing else changes, you hit target T when k ≥ (T × n − P + D) ÷ (1 − T), with T as a decimal. In the example, going from 45 to 50 takes 20 more promoters: (0.5 × 200 − 120 + 30) ÷ 0.5. Winning over detractors pays double, because each one leaves one side and lands on the other: 5 would do it.

To see what each new customer costs you and whether it pays off, the ROI calculator ties spend, revenue and margin together. There are more free marketing tools on the hub, too.

Net Promoter and NPS are registered trademarks, and Net Promoter Score is a service mark, of Bain & Company, Inc., NICE Systems, Inc. and Fred Reichheld.

Frequently asked questions about NPS

01

What is a good NPS score?

Anything above 0 means you have more promoters than detractors, and that’s the first bar to clear. Past that, be wary of benchmark tables with no source: NPS swings a lot by industry, country and the moment you ask. The useful comparison is with yourself, quarter over quarter, with the same question and the same channel, while watching whether the confidence interval actually moves up.

02

Is 70% NPS good?

First, NPS isn’t a percentage: a 70 is read as “70,” not “70%.” And a 70 means promoters outnumber detractors by 70 points, so at least 7 out of 10 people who answered gave you a 9 or a 10. That’s a strong signal of word of mouth. Before you celebrate, check the margin of error: with 40 responses, a 70 could really be anywhere in a wide range.

03

How do you calculate NPS in Excel?

Put the 0-10 scores in column A and use =(COUNTIF(A:A,">=9")-COUNTIF(A:A,"<=6"))/COUNT(A:A)*100. The first COUNTIF counts promoters, the second counts detractors and COUNT gives total responses, passives included. It works the same in Google Sheets. If you’d rather skip formulas, copy the column and paste it into the calculator: you also get the score distribution and the margin of error.

04

How do you calculate NPS on a 5-point scale?

Strictly speaking, you can’t. Net Promoter Score is defined on a 0 to 10 scale, with 9-10 as promoters and 0-6 as detractors, and there’s no official way to convert a 1 to 5 rating. If you already run a 5-point survey, call it a custom loyalty metric, keep the rules fixed over time, and switch to the 0-10 question when you want a number you can compare.