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Uncapped SAFEs: the dilution you can't see until you price

An uncapped SAFE has no valuation cap, so it converts at the priced round's own price — minus any discount. That sounds founder-friendly, and often it is. But it has one uncomfortable property: you cannot know its dilution until you set a valuation you haven't set yet. It's a blank in your model until the round prices. Here's how to reason about it anyway.

How an uncapped SAFE converts

With no cap, there's nothing to compare the round price against — the SAFE simply rides the round:

discount-only: conversion price = round price × (1 − discount) no cap, no discount: conversion price = round price (no benefit at all)

The key consequence: the SAFE's ownership percentage is not fixed at signing the way a capped post-money SAFE's is. It depends entirely on the round price, which depends on the pre-money you negotiate later. A strong round means the SAFE buys fewer, more expensive shares; a weak round means it buys many cheap ones.

Worked example — a discount-only SAFE across two rounds

Take the same $500,000 SAFE with a 20% discount and no cap, against 8,000,000 founder shares, and price the round two ways.

RoundRound priceSAFE price (−20%)SAFE sharesSAFE %
Strong: $12M pre, $3M in$1.50$1.20416,6674.0%
Weak: $3M pre, $1M in$0.375$0.301,666,66713.5%
Same SAFE, same $500k — but 4.0% in a strong round and 13.5% in a weak one, more than three times the dilution. With a capped SAFE you'd know your worst case in advance (the cap sets a floor on the price). With an uncapped SAFE, your dilution is a live function of a number you're still negotiating. That uncertainty is the whole point of modeling a range. All four figures are the engine's output for these inputs.

The uncapped-plus-MFN trap

An uncapped SAFE with an MFN clause is the worst of both worlds for a founder. It starts uncapped — no protection for you — but the MFN means the moment you issue a capped SAFE later, this one inherits that cap. So it converts to "no cap" only if you never sign anything cheaper; the instant you do, it silently adopts your best cap. You've written an option that you fund. See the MFN guide for the backflow math.

How to reason about an uncapped SAFE in your model

Caveat. The figures above are directional and depend on the exact pre-money, existing shares, pool, and any discount cap in your document. Uncapped SAFEs also interact with the rest of your stack (they're diluted by capped SAFEs converting alongside them). Model your real numbers, and have counsel confirm the terms. Not investment, legal, or tax advice.

See your uncapped exposure as a range

The report converts every uncapped or discount-only SAFE across the bear / base / bull rounds you're weighing — and flags it on the warning map, with the MFN interaction called out.

Try the free estimate Get the report — $390

Related guides

Cap vs discount: which one applies → MFN clauses: how later terms flow backward → Bear / base / bull: modeling the dilution range →