Vesting Schedules Explained: Cliff, Acceleration, and 83(b)

Startup equity vesting can be confusing. This guide explains standard vesting schedules, how cliff periods work, the difference between single and double trigger acceleration, and why your 83(b) election deadline matters more than you think.

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Table of Contents

1. What is a Vesting Schedule?
2. The Standard 4-Year Vesting Schedule
3. How the Cliff Period Works
4. Vesting Frequency: Monthly vs Quarterly vs Annual
5. Acceleration: Single vs Double Trigger
6. Understanding the 83(b) Election
7. Calculating Your Vesting
8. Key Takeaways

What is a Vesting Schedule?

A vesting schedule determines when you actually own the equity you've been granted. You don't get all your shares upfront—you earn them over time by staying with the company.

This protects both sides:

• The company — If you leave early, they can reclaim your unvested shares and give them to someone else
• You — Your shares can't be taken away arbitrarily once they vest. You own them.

The Standard 4-Year Vesting Schedule

The industry standard for startup equity is 4-year vesting with a 1-year cliff.

You vest 1/48th of your shares each month (about 2.08% per month), or 25% per year.

Time at Company	Shares Vested	Unvested Shares
Day 1	0	100%
11 months	0	100%
12 months (cliff)	25%	75%
24 months	50%	50%
36 months	75%	25%
48 months	100%	0%

How the Cliff Period Works

The cliff is a waiting period before your vesting starts. During this time, you earn 0 shares—regardless of how much time you've put in.

Once you hit the cliff at 12 months, you immediately vest a lump sum of 25% of your shares. After that, you vest monthly or quarterly depending on your schedule.

Vesting Frequency: Monthly vs Quarterly vs Annual

After the cliff, how often do your shares vest?

Frequency	How It Works	Pros/Cons
Monthly	Vest ~2.08% each month	Pros: Fair, less risk on departure Cons: More administrative work
Quarterly	Vest ~6.25% every 3 months	Pros: Common, balanced Cons: Risky to leave mid-quarter
Annual	Vest 25% at year-end	Pros: Simple administration Cons: Bad for employees—leaving at month 23 means you get only year 1 vested

Acceleration: Single vs Double Trigger

Acceleration provisions allow some or all of your unvested shares to vest immediately if certain events occur. These are typically negotiated for executives and founders.

Single-Trigger Acceleration

Single-trigger acceleration means one event causes immediate vesting of a portion of your unvested shares.

A "Change of Control" is usually an acquisition or merger. Single-trigger acceleration provides a safety net if the company is sold before your shares vest.

Double-Trigger Acceleration

Double-trigger acceleration requires two events for acceleration to occur:

1. First trigger: Change of Control (acquisition/merger)
2. Second trigger: Termination without cause or constructive termination

This is more common and company-friendly. If the company is acquired but you stay employed, you don't get accelerated vesting. You only get it if the acquisition and you're let go.

Understanding the 83(b) Election

The 83(b) election is a tax filing that can save you massive amounts of money on startup equity. But you have to file it within 30 days of receiving your grant—or it's gone forever.

How Equity Taxation Works

When you receive stock options, you don't owe tax immediately. You pay tax when you exercise your options (buy the shares) and when those shares are sold.

The tax you pay depends on the difference between:

• Strike price — What you pay to buy the shares
• Fair Market Value (FMV) — What the shares are worth when you exercise

What 83(b) Does

An 83(b) election lets you pay tax upfront on the spread between your strike price and the current FMV, rather than paying as the shares vest and the FMV increases.

Scenario	Strike Price	FMV (at grant)	Spread
Without 83(b)	$0.10	$0.10	$0.00
With 83(b)	$0.10	$0.10	$0.00

At grant time, when FMV equals strike price, the spread is $0—so filing 83(b) costs you $0 in tax today. But it locks in that low tax basis.

The Savings Add Up

Let's say you receive 100,000 options at $0.10/share strike price. Current FMV is $0.10.

Without 83(b):

• As shares vest, FMV grows to $1.00, $5.00, $20.00...
• You pay ordinary income tax on (FMV - $0.10) at vesting
• 100,000 shares × $19.90 spread × 37% tax bracket = $736,300 in taxes

With 83(b):

• You pay tax today on $0 spread = $0
• Later, when shares vest, you've already paid
• When you sell, you pay capital gains on (sale price - $0.10)
• Capital gains (20%) vs ordinary income (37%) = significant savings

Calculating Your Vesting

Use our free vesting calculator to understand:

• Exactly how many shares you've vested to date
• How many shares remain unvested
• The current value of your vested shares
• Your vesting timeline with cliff visualization
• What happens on acceleration triggers
• Compare different vesting scenarios

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Key Takeaways

• Standard vesting is 4 years with a 1-year cliff
• You get 0 shares if you leave before the cliff—even 1 day early
• After the cliff, you vest ~2.08% monthly (25% annually)
• Monthly vesting is fairest; annual vesting penalizes mid-year departures
• Single-trigger acceleration vests on acquisition alone
• Double-trigger acceleration requires acquisition + termination
• File your 83(b) election within 30 days of grant—no exceptions
• 83(b) can save hundreds of thousands in taxes for early-stage employees