diff --git a/headers/vmath.hpp/vmath_fun.hpp b/headers/vmath.hpp/vmath_fun.hpp
new file mode 100644
index 0000000..de6146e
--- /dev/null
+++ b/headers/vmath.hpp/vmath_fun.hpp
@@ -0,0 +1,169 @@
+/*******************************************************************************
+ * This file is part of the "https://github.com/blackmatov/vmath.hpp"
+ * For conditions of distribution and use, see copyright notice in LICENSE.md
+ * Copyright (C) 2020, by Matvey Cherevko (blackmatov@gmail.com)
+ ******************************************************************************/
+
+#pragma once
+
+#include "vmath_fwd.hpp"
+
+//
+// Angle and Trigonometry Functions
+//
+
+namespace vmath_hpp
+{
+    template < typename T >
+    constexpr T radians(T degrees) noexcept {
+        return degrees * T(0.01745329251994329576923690768489);
+    }
+
+    template < typename T >
+    constexpr T degrees(T radians) noexcept {
+        return radians * T(57.295779513082320876798154814105);
+    }
+
+    using ::std::sin;
+    using ::std::cos;
+    using ::std::tan;
+
+    using ::std::asin;
+    using ::std::acos;
+    using ::std::atan;
+    using ::std::atan2;
+
+    using ::std::sinh;
+    using ::std::cosh;
+    using ::std::tanh;
+
+    using ::std::asinh;
+    using ::std::acosh;
+    using ::std::atanh;
+}
+
+//
+// Exponential Functions
+//
+
+namespace vmath_hpp
+{
+    using ::std::pow;
+    using ::std::exp;
+    using ::std::log;
+    using ::std::exp2;
+    using ::std::log2;
+    using ::std::sqrt;
+
+    template < typename T >
+    T invsqrt(T x) noexcept {
+        return T(1) / sqrt(x);
+    }
+}
+
+//
+// Common Functions
+//
+
+namespace vmath_hpp
+{
+    using ::std::abs;
+
+    template < typename T >
+    T sign(T x) noexcept {
+        return (T(0) < x) - (x < T(0));
+    }
+
+    using ::std::floor;
+    using ::std::trunc;
+    using ::std::round;
+    using ::std::ceil;
+
+    template < typename T >
+    T fract(T x) noexcept {
+        return x - floor(x);
+    }
+
+    using ::std::fmod;
+    using ::std::modf;
+
+    using ::std::min;
+    using ::std::max;
+
+    template < typename T >
+    constexpr T clamp(T x, T min_x, T max_x) noexcept {
+        return min(max(x, min_x), max_x);
+    }
+
+    template < typename T >
+    constexpr T mix(T x, T y, T a) noexcept {
+        return x * (T(1) - a) + y * a;
+    }
+
+    template < typename T >
+    constexpr T mix(T x, T y, bool a) noexcept {
+        return a ? y : x;
+    }
+
+    template < typename T >
+    constexpr T step(T edge, T x) noexcept {
+        return x < edge ? T(0) : T(1);
+    }
+
+    template < typename T >
+    constexpr T smoothstep(T edge0, T edge1, T x) noexcept {
+        const T t = clamp((x - edge0) / (edge1 - edge0), T(0), T(1));
+        return t * t * (T(3) - T(2) * t);
+    }
+
+    using ::std::isnan;
+    using ::std::isinf;
+    using ::std::fma;
+
+    using ::std::frexp;
+    using ::std::ldexp;
+}
+
+//
+// Geometric Functions
+//
+
+namespace vmath_hpp
+{
+    template < typename T >
+    T length(T x) noexcept {
+        return abs(x);
+    }
+
+    template < typename T >
+    T distance(T p0, T p1) noexcept {
+        return length(p0 - p1);
+    }
+
+    template < typename T >
+    T dot(T x, T y) noexcept {
+        return x * y;
+    }
+
+    template < typename T >
+    T normalize(T x) noexcept {
+        return x * invsqrt(dot(x, x));
+    }
+
+    template < typename T >
+    T faceforward(T n, T i, T nref) noexcept {
+        return dot(nref, i) < T(0) ? n : -n;
+    }
+
+    template < typename T >
+    T reflect(T i, T n) noexcept {
+        return i - n * dot(n, i) * T(2);
+    }
+
+    template < typename T >
+    T refract(T i, T n, T eta) noexcept {
+        const T d = dot(n, i);
+        const T k = T(1) - eta * eta * (T(1) - d * d);
+        return T(k >= T(0)) * (eta * i - (eta * d + sqrt(k)) * n);
+    }
+}
diff --git a/headers/vmath.hpp/vmath_fwd.hpp b/headers/vmath.hpp/vmath_fwd.hpp
index 7657dbb..be41369 100644
--- a/headers/vmath.hpp/vmath_fwd.hpp
+++ b/headers/vmath.hpp/vmath_fwd.hpp
@@ -10,6 +10,7 @@
 #include <cmath>
 #include <cstddef>
 
+#include <algorithm>
 #include <functional>
 #include <iterator>
 #include <stdexcept>
diff --git a/untests/vmath_fun_tests.cpp b/untests/vmath_fun_tests.cpp
new file mode 100644
index 0000000..715bc58
--- /dev/null
+++ b/untests/vmath_fun_tests.cpp
@@ -0,0 +1,135 @@
+/*******************************************************************************
+ * This file is part of the "https://github.com/blackmatov/vmath.hpp"
+ * For conditions of distribution and use, see copyright notice in LICENSE.md
+ * Copyright (C) 2020, by Matvey Cherevko (blackmatov@gmail.com)
+ ******************************************************************************/
+
+#include <vmath.hpp/vmath_fun.hpp>
+
+#define CATCH_CONFIG_FAST_COMPILE
+#include <catch2/catch.hpp>
+
+namespace
+{
+    template < typename T >
+    class approx {
+    public:
+        explicit constexpr approx(T v) : value_(v) {}
+
+        friend constexpr bool operator==(const T& l, const approx& r) {
+            return (r.value_ < l + epsilon)
+                && (l < r.value_ + epsilon);
+        }
+    private:
+        T value_;
+        static constexpr T epsilon = std::numeric_limits<T>::epsilon() * 100;
+    };
+}
+
+TEST_CASE("vmath/fun") {
+    using namespace vmath_hpp;
+
+    SECTION("Angle and Trigonometry Functions") {
+        STATIC_REQUIRE(radians(degrees(12.13f)) == approx(12.13f));
+        STATIC_REQUIRE(degrees(radians(12.13f)) == approx(12.13f));
+
+        sin(0.f);
+        cos(0.f);
+        tan(0.f);
+
+        asin(0.f);
+        acos(0.f);
+        atan(0.f);
+        atan2(0.f, 0.f);
+
+        sinh(0.f);
+        cosh(0.f);
+        tanh(0.f);
+
+        asinh(0.f);
+        acosh(0.f);
+        atanh(0.f);
+    }
+
+    SECTION("Exponential Functions") {
+        pow(2.f, 3.f);
+        exp(2.f);
+        log(2.f);
+        exp2(2.f);
+        log2(2.f);
+        sqrt(2.f);
+        invsqrt(2.f);
+    }
+
+    SECTION("Common Functions") {
+        REQUIRE(abs(1) == 1);
+        REQUIRE(abs(-1) == 1);
+        REQUIRE(abs(1.f) == approx(1.f));
+        REQUIRE(abs(-1.f) == approx(1.f));
+
+        REQUIRE(sign(2) == 1);
+        REQUIRE(sign(-2) == -1);
+        REQUIRE(sign(0) == 0);
+        REQUIRE(sign(2.f) == approx(1.f));
+        REQUIRE(sign(-2.f) == approx(-1.f));
+        REQUIRE(sign(0.f) == approx(0.f));
+
+        REQUIRE(floor(1.7f) == approx(1.f));
+        REQUIRE(trunc(1.7f) == approx(1.f));
+        REQUIRE(round(1.7f) == approx(2.f));
+        REQUIRE(ceil(1.7f) == approx(2.f));
+
+        REQUIRE(fract(1.7f) == approx(0.7f));
+        REQUIRE(fract(-2.3f) == approx(0.7f));
+
+        REQUIRE(fmod(1.7f, 1.2f) == approx(0.5f));
+
+        {
+            float out_i{};
+            REQUIRE(modf(1.7f, &out_i) == approx(0.7f));
+            REQUIRE(out_i == approx(1.f));
+        }
+
+        STATIC_REQUIRE(min(1.f, 2.f) == approx(1.f));
+        STATIC_REQUIRE(max(1.f, 2.f) == approx(2.f));
+
+        STATIC_REQUIRE(clamp(1.0f, 2.f, 3.f) == approx(2.0f));
+        STATIC_REQUIRE(clamp(2.5f, 2.f, 3.f) == approx(2.5f));
+        STATIC_REQUIRE(clamp(3.5f, 2.f, 3.f) == approx(3.0f));
+
+        STATIC_REQUIRE(mix(0.f, 10.f, 0.5f) == approx(5.f));
+        STATIC_REQUIRE(mix(0.f, 10.f, false) == approx(0.f));
+        STATIC_REQUIRE(mix(0.f, 10.f, true) == approx(10.f));
+        STATIC_REQUIRE(step(0.5f, 0.4f) == approx(0.f));
+        STATIC_REQUIRE(step(0.5f, 0.6f) == approx(1.f));
+        STATIC_REQUIRE(smoothstep(0.f, 1.f, 0.1f) == approx(0.028f));
+
+        REQUIRE_FALSE(isnan(1.f));
+        REQUIRE_FALSE(isinf(1.f));
+
+        REQUIRE(fma(2.f, 3.f, 4.f) == approx(10.f));
+
+        {
+            int out_exp{};
+            REQUIRE(frexp(1.7f, &out_exp) == approx(0.85f));
+            REQUIRE(out_exp == 1);
+        }
+
+        REQUIRE(ldexp(0.85f, 1) == approx(1.7f));
+    }
+
+    SECTION("Geometric Functions") {
+        REQUIRE(length(10.f) == approx(10.f));
+        REQUIRE(length(-10.f) == approx(10.f));
+
+        REQUIRE(distance(5.f, 10.f) == approx(5.f));
+        REQUIRE(distance(-5.f, -10.f) == approx(5.f));
+
+        REQUIRE(dot(2.f, 5.f) == approx(10.f));
+        REQUIRE(normalize(0.5f) == approx(1.f));
+
+        REQUIRE(faceforward(1.f, 2.f, 3.f) == approx(-1.f));
+        REQUIRE(reflect(1.f, 2.f) == approx(-7.f));
+        REQUIRE(refract(1.f, 2.f, 1.f) == approx(-7.f));
+    }
+}