What does the signup conversion calculator do?

It estimates the annual dollar cost of signup friction. Enter monthly signup starts, current completion rate, number of form fields, presence of email verification or captcha, OAuth availability, and your LTV and CAC. It outputs the annual signups you currently get, the annual signups you would get with the friction removed, and the dollar delta.

How accurate is the calculator?

The per-field drop-off coefficient is 8% per field beyond the second, the conservative end of Baymard's aggregated 8-10pp range. Email verification gate drop is 12pp (midpoint of Auth0's 8-20pp). Captcha drop is 3pp. OAuth lift is 18pp (midpoint of the 15-25pp B2C / 8-15pp B2B social-login range). Outputs are directional estimates, not predictions for your specific flow.

Is the calculator free?

Yes. No signup required to use it; the page is fully client-side. No data leaves your browser; we do not store inputs.

Last verified June 2026 · 5 min read

Signup conversion calculator

Enter your funnel metrics. The calculator surfaces the dollar cost of each friction step: extra fields, email verify gates, captcha, OAuth lift. All math runs client-side. No data leaves your browser.

SIGNUP FLOW COST CALCULATOR

Monthly signup starts

Current completion rate (%)

Number of form fields

User LTV ($)

CAC per signup ($)

Email verification required?Captcha present?OAuth offered?

ANNUAL SIGNUPS

27,000

PER-EXTRA-FIELD COST/YR

$3.8M

POTENTIAL ANNUAL SAVINGS

$13.4M

by applying research-backed friction reduction (+28pp)

The dollar figure above is the upside of one change. Before you bank it, size the test that proves it. This sends your 45% baseline into the estimator into the duration estimator below.

EXPERIMENT PLANNING

A/B test duration estimator

Most signup-page tests run for too short a duration to detect the lift they claim. Enter your baseline rate, the relative lift you care about catching, and your daily traffic. The calculator returns sample size per variant, days needed, and an honest feasibility verdict.

Baseline conversion rate

Minimum detectable lift (relative)

Relative lift. 10% MDE on a 5% baseline means detecting a rise to 5.5%.

Daily users entering experiment

/day

Split 50/50 between control and variant.

Statistical power

80% is the standard default. 90% needs roughly 30% more sample but reduces false-negative risk.

SAMPLE SIZE PER VARIANT

31,232

62,464 total (31,232 control + 31,232 variant)

Days needed

Weeks needed

4.6

FEASIBLE

Reasonable duration. Aim to start on a Monday so the test ends on a clean weekly boundary.

Uses the standard two-proportion z-test sample-size formula with two-sided alpha = 0.05. Assumes 50/50 traffic split with no sequential testing. If you peek at results early, the false-positive rate is higher than the nominal 5% - use a sequential testing framework (e.g., Bayesian or always-valid CIs) instead of just a fixed-horizon design.

WORKED EXAMPLES

Three worked examples

B2C SAAS

Inputs: 10,000 monthly starts, 45% current rate, 4 fields, hard email gate, no captcha, no OAuth, $200 LTV, $40 CAC

Fields: 2 fields beyond the baseline of 2 = 16% drop component.
Gate: Email verify gate adds 12pp drop.
Captcha: Off.
OAuth: Off (no OAuth offered).

Headline: Removing the email gate and two redundant fields could lift conversion from 45% to roughly 60%; 10,000 starts at $200 LTV implies roughly $360K in additional annual LTV captured. Adding Google OAuth would add another approximately 15pp lift.

B2B SAAS

Inputs: 2,000 monthly starts, 30% current rate, 6 fields, soft verify, reCAPTCHA on, no OAuth, $1500 LTV, $200 CAC

Fields: 4 fields beyond the baseline of 2 = 32% drop component (B2B norms tolerate more fields, but not all 4 are earning their keep).
Gate: Soft verify only, no hard gate drop.
Captcha: reCAPTCHA v2: 3pp drop.
OAuth: Off (B2B corporate OAuth politics often justified).

Headline: Per the audit: 2 of the 4 extra fields are progressive-profile candidates; switching captcha to Cloudflare Turnstile and progressive-profiling the role + company-size fields could lift conversion from 30% to roughly 42%, worth approximately $540K annual LTV.

ECOMMERCE

Inputs: 20,000 monthly starts, 55% current rate, 3 fields, no verify gate, no captcha, OAuth on, $80 LTV, $20 CAC

Fields: 1 field beyond baseline = 8% drop component.
Gate: No verify gate (ecom typically defers verification until checkout).
Captcha: Off.
OAuth: On: Google + Apple Sign In lifting 18pp.

Headline: Conversion is already healthy. Marginal lift from removing the third field is approximately 8pp; at 20,000 starts and $80 LTV that is roughly $154K additional annual LTV. The bigger leverage is post-signup activation, not signup itself.

How the math works

The calculator applies six cited adjustments to the base completion rate.

Per-field drop: 8% per field beyond the second (Baymard aggregated checkout-form research, conservative end of 8-10pp).
Email verify hard gate: 12pp drop midpoint (Auth0 reports 8-20pp; we use the midpoint).
Captcha: 3pp drop (Cloudflare Turnstile and Google reCAPTCHA published benchmarks; reCAPTCHA v2 checkbox is 2-5pp, Turnstile is under 1pp, we use 3pp as a calculator-default mid-band).
OAuth lift: 18pp midpoint (aggregated social-login studies: +15-25pp B2C / +8-15pp B2B).
LTV multiplier: Your LTV input drives the dollar conversion. We do not haircut LTV for expansion revenue; that is your call.
CAC waste: Annual lost signups times current CAC; surfaces the second-order CAC cost of friction.

The four friction adjustments do not stack linearly; the calculator caps the combined drop at 35pp to keep outputs inside realistic ranges. Full source list at /methodology.

How to use the output

The headline number is directional, not a forecast. The right use is to support the decision to A/B test a specific change (drop a field, switch to verify-later, swap captcha provider, add OAuth) by attaching a defensible dollar figure to the upside. If the calculator says removing two fields is worth $360K, that does not mean you will see $360K next year; it means the upside is large enough to justify the engineering work to run the test.

For benchmark context per industry and segment, see /benchmarks and /signup-conversion-by-industry.

DIGITAL SIGNET CONSULTING

Need an outside eye on your signup funnel?

Digital Signet runs two-week signup-funnel audits. We map the drop-off at every step, attach the dollar cost to each field, and deliver the memo your growth team will sign.

See the engagement format